Commit Graph

423 Commits

Author SHA1 Message Date
Stefano Stabellini
c9fb47e7d0 9p: introduce a type for the 9p header
Use the new type in virtio-9p-device.

Signed-off-by: Stefano Stabellini <stefano@aporeto.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
CC: anthony.perard@citrix.com
CC: jgross@suse.com
CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
CC: Greg Kurz <groug@kaod.org>
2017-04-21 12:41:29 -07:00
Greg Kurz
9c6b899f7a 9pfs: local: set the path of the export root to "."
The local backend was recently converted to using "at*()" syscalls in order
to ensure all accesses happen below the shared directory. This requires that
we only pass relative paths, otherwise the dirfd argument to the "at*()"
syscalls is ignored and the path is treated as an absolute path in the host.
This is actually the case for paths in all fids, with the notable exception
of the root fid, whose path is "/". This causes the following backend ops to
act on the "/" directory of the host instead of the virtfs shared directory
when the export root is involved:
- lstat
- chmod
- chown
- utimensat

ie, chmod /9p_mount_point in the guest will be converted to chmod / in the
host for example. This could cause security issues with a privileged QEMU.

All "*at()" syscalls are being passed an open file descriptor. In the case
of the export root, this file descriptor points to the path in the host that
was passed to -fsdev.

The fix is thus as simple as changing the path of the export root fid to be
"." instead of "/".

This is CVE-2017-7471.

Cc: qemu-stable@nongnu.org
Reported-by: Léo Gaspard <leo@gaspard.io>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-04-18 14:01:43 +01:00
Li Qiang
4ffcdef427 9pfs: xattr: fix memory leak in v9fs_list_xattr
Free 'orig_value' in error path.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-04-10 09:38:05 +02:00
Greg Kurz
6d54af0ea9 9pfs: clear migration blocker at session reset
The migration blocker survives a device reset: if the guest mounts a 9p
share and then gets rebooted with system_reset, it will be unmigratable
until it remounts and umounts the 9p share again.

This happens because the migration blocker is supposed to be cleared when
we put the last reference on the root fid, but virtfs_reset() wrongly calls
free_fid() instead of put_fid().

This patch fixes virtfs_reset() so that it honor the way fids are supposed
to be manipulated: first get a reference and later put it back when you're
done.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Li Qiang <liqiang6-s@360.cn>
2017-04-04 18:06:01 +02:00
Greg Kurz
18adde86dd 9pfs: fix multiple flush for same request
If a client tries to flush the same outstanding request several times, only
the first flush completes. Subsequent ones keep waiting for the request
completion in v9fs_flush() and, therefore, leak a PDU. This will cause QEMU
to hang when draining active PDUs the next time the device is reset.

Let have each flush request wake up the next one if any. The last waiter
frees the cancelled PDU.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-04-04 18:06:01 +02:00
Li Qiang
d63fb193e7 9pfs: fix file descriptor leak
The v9fs_create() and v9fs_lcreate() functions are used to create a file
on the backend and to associate it to a fid. The fid shouldn't be already
in-use, otherwise both functions may silently leak a file descriptor or
allocated memory. The current code doesn't check that.

This patch ensures that the fid isn't already associated to anything
before using it.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
(reworded the changelog, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-03-27 21:13:19 +02:00
Greg Kurz
262169abe7 9pfs: proxy: assert if unmarshal fails
Replies from the virtfs proxy are made up of a fixed-size header (8 bytes)
and a payload of variable size (maximum 64kb). When receiving a reply,
the proxy backend first reads the whole header and then unmarshals it.
If the header is okay, it then does the same operation with the payload.

Since the proxy backend uses a pre-allocated buffer which has enough room
for a header and the maximum payload size, marshalling should never fail
with fixed size arguments. Any error here is likely to result from a more
serious corruption in QEMU and we'd better dump core right away.

This patch adds error checks where they are missing and converts the
associated error paths into assertions.

This should also address Coverity's complaints CID 1348519 and CID 1348520,
about not always checking the return value of proxy_unmarshal().

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2017-03-21 09:12:47 +01:00
Greg Kurz
d5f2af7b95 9pfs: don't try to flush self and avoid QEMU hang on reset
According to the 9P spec [*], when a client wants to cancel a pending I/O
request identified by a given tag (uint16), it must send a Tflush message
and wait for the server to respond with a Rflush message before reusing this
tag for another I/O. The server may still send a completion message for the
I/O if it wasn't actually cancelled but the Rflush message must arrive after
that.

QEMU hence waits for the flushed PDU to complete before sending the Rflush
message back to the client.

If a client sends 'Tflush tag oldtag' and tag == oldtag, QEMU will then
allocate a PDU identified by tag, find it in the PDU list and wait for
this same PDU to complete... i.e. wait for a completion that will never
happen. This causes a tag and ring slot leak in the guest, and a PDU
leak in QEMU, all of them limited by the maximal number of PDUs (128).
But, worse, this causes QEMU to hang on device reset since v9fs_reset()
wants to drain all pending I/O.

This insane behavior is likely to denote a bug in the client, and it would
deserve an Rerror message to be sent back. Unfortunately, the protocol
allows it and requires all flush requests to suceed (only a Tflush response
is expected).

The only option is to detect when we have to handle a self-referencing
flush request and report success to the client right away.

[*] http://man.cat-v.org/plan_9/5/flush

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-03-21 09:12:47 +01:00
Greg Kurz
b003fc0d8a 9pfs: fix vulnerability in openat_dir() and local_unlinkat_common()
We should pass O_NOFOLLOW otherwise openat() will follow symlinks and make
QEMU vulnerable.

While here, we also fix local_unlinkat_common() to use openat_dir() for
the same reasons (it was a leftover in the original patchset actually).

This fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-06 17:34:01 +01:00
Greg Kurz
918112c02a 9pfs: fix O_PATH build break with older glibc versions
When O_PATH is used with O_DIRECTORY, it only acts as an optimization: the
openat() syscall simply finds the name in the VFS, and doesn't trigger the
underlying filesystem.

On systems that don't define O_PATH, because they have glibc version 2.13
or older for example, we can safely omit it. We don't want to deactivate
O_PATH globally though, in case it is used without O_DIRECTORY. The is done
with a dedicated macro.

Systems without O_PATH may thus fail to resolve names that involve
unreadable directories, compared to newer systems succeeding, but such
corner case failure is our only option on those older systems to avoid
the security hole of chasing symlinks inappropriately.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
(added last paragraph to changelog as suggested by Eric Blake)
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-03-06 17:34:01 +01:00
Greg Kurz
b314f6a077 9pfs: don't use AT_EMPTY_PATH in local_set_cred_passthrough()
The name argument can never be an empty string, and dirfd always point to
the containing directory of the file name. AT_EMPTY_PATH is hence useless
here. Also it breaks build with glibc version 2.13 and older.

It is actually an oversight of a previous tentative patch to implement this
function. We can safely drop it.

Reported-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Greg Kurz <groug@kaod.org>
Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-06 17:34:01 +01:00
Greg Kurz
23da0145cc 9pfs: fail local_statfs() earlier
If we cannot open the given path, we can return right away instead of
passing -1 to fstatfs() and close(). This will make Coverity happy.

(Coverity issue CID1371729)

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Daniel P. berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2017-03-06 17:34:01 +01:00
Greg Kurz
faab207f11 9pfs: fix fd leak in local_opendir()
Coverity issue CID1371731

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2017-03-06 17:34:01 +01:00
Greg Kurz
b7361d46e7 9pfs: fix bogus fd check in local_remove()
This was spotted by Coverity as a fd leak. This is certainly true, but also
local_remove() would always return without doing anything, unless the fd is
zero, which is very unlikely.

(Coverity issue CID1371732)

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
2017-03-06 17:34:01 +01:00
Peter Maydell
7287e3556f This pull request have all the fixes for CVE-2016-9602, so that it can
be easily picked up by downstreams, as suggested by Michel Tokarev.
 -----BEGIN PGP SIGNATURE-----
 
 iEYEABECAAYFAli1TywACgkQAvw66wEB28Lq+gCeKV58yNI4imzrSdowADsO+x96
 hvcAmwaXc+3m/l/eEuCe8g2qxyiBZ6Bi
 =4/LM
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Merge remote-tracking branch 'remotes/gkurz/tags/cve-2016-9602-for-upstream' into staging

This pull request have all the fixes for CVE-2016-9602, so that it can
be easily picked up by downstreams, as suggested by Michel Tokarev.

# gpg: Signature made Tue 28 Feb 2017 10:21:32 GMT
# gpg:                using DSA key 0x02FC3AEB0101DBC2
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg:                 aka "Greg Kurz <groug@free.fr>"
# gpg:                 aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg:                 aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg:                 aka "[jpeg image of size 3330]"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894  DBA2 02FC 3AEB 0101 DBC2

* remotes/gkurz/tags/cve-2016-9602-for-upstream: (28 commits)
  9pfs: local: drop unused code
  9pfs: local: open2: don't follow symlinks
  9pfs: local: mkdir: don't follow symlinks
  9pfs: local: mknod: don't follow symlinks
  9pfs: local: symlink: don't follow symlinks
  9pfs: local: chown: don't follow symlinks
  9pfs: local: chmod: don't follow symlinks
  9pfs: local: link: don't follow symlinks
  9pfs: local: improve error handling in link op
  9pfs: local: rename: use renameat
  9pfs: local: renameat: don't follow symlinks
  9pfs: local: lstat: don't follow symlinks
  9pfs: local: readlink: don't follow symlinks
  9pfs: local: truncate: don't follow symlinks
  9pfs: local: statfs: don't follow symlinks
  9pfs: local: utimensat: don't follow symlinks
  9pfs: local: remove: don't follow symlinks
  9pfs: local: unlinkat: don't follow symlinks
  9pfs: local: lremovexattr: don't follow symlinks
  9pfs: local: lsetxattr: don't follow symlinks
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-03-01 13:53:20 +00:00
Greg Kurz
c23d5f1d5b 9pfs: local: drop unused code
Now that the all callbacks have been converted to use "at" syscalls, we
can drop this code.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
a565fea565 9pfs: local: open2: don't follow symlinks
The local_open2() callback is vulnerable to symlink attacks because it
calls:

(1) open() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_open2() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively. Since local_open2() already opens
a descriptor to the target file, local_set_cred_passthrough() is
modified to reuse it instead of opening a new one.

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to openat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
3f3a16990b 9pfs: local: mkdir: don't follow symlinks
The local_mkdir() callback is vulnerable to symlink attacks because it
calls:

(1) mkdir() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_mkdir() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively.

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mkdirat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
d815e72190 9pfs: local: mknod: don't follow symlinks
The local_mknod() callback is vulnerable to symlink attacks because it
calls:

(1) mknod() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_mknod() to rely on opendir_nofollow() and
mknodat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.

A new local_set_cred_passthrough() helper based on fchownat() and
fchmodat_nofollow() is introduced as a replacement to
local_post_create_passthrough() to fix (4).

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mknodat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
38771613ea 9pfs: local: symlink: don't follow symlinks
The local_symlink() callback is vulnerable to symlink attacks because it
calls:

(1) symlink() which follows symbolic links for all path elements but the
    rightmost one
(2) open(O_NOFOLLOW) which follows symbolic links for all path elements but
    the rightmost one
(3) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(4) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

This patch converts local_symlink() to rely on opendir_nofollow() and
symlinkat() to fix (1), openat(O_NOFOLLOW) to fix (2), as well as
local_set_xattrat() and local_set_mapped_file_attrat() to fix (3) and
(4) respectively.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
d369f20763 9pfs: local: chown: don't follow symlinks
The local_chown() callback is vulnerable to symlink attacks because it
calls:

(1) lchown() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

This patch converts local_chown() to rely on open_nofollow() and
fchownat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
e3187a45dd 9pfs: local: chmod: don't follow symlinks
The local_chmod() callback is vulnerable to symlink attacks because it
calls:

(1) chmod() which follows symbolic links for all path elements
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

We would need fchmodat() to implement AT_SYMLINK_NOFOLLOW to fix (1). This
isn't the case on linux unfortunately: the kernel doesn't even have a flags
argument to the syscall :-\ It is impossible to fix it in userspace in
a race-free manner. This patch hence converts local_chmod() to rely on
open_nofollow() and fchmod(). This fixes the vulnerability but introduces
a limitation: the target file must readable and/or writable for the call
to openat() to succeed.

It introduces a local_set_xattrat() replacement to local_set_xattr()
based on fsetxattrat() to fix (2), and a local_set_mapped_file_attrat()
replacement to local_set_mapped_file_attr() based on local_fopenat()
and mkdirat() to fix (3). No effort is made to factor out code because
both local_set_xattr() and local_set_mapped_file_attr() will be dropped
when all users have been converted to use the "at" versions.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
ad0b46e6ac 9pfs: local: link: don't follow symlinks
The local_link() callback is vulnerable to symlink attacks because it calls:

(1) link() which follows symbolic links for all path elements but the
    rightmost one
(2) local_create_mapped_attr_dir()->mkdir() which follows symbolic links
    for all path elements but the rightmost one

This patch converts local_link() to rely on opendir_nofollow() and linkat()
to fix (1), mkdirat() to fix (2).

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
6dd4b1f1d0 9pfs: local: improve error handling in link op
When using the mapped-file security model, we also have to create a link
for the metadata file if it exists. In case of failure, we should rollback.

That's what this patch does.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
d2767edec5 9pfs: local: rename: use renameat
The local_rename() callback is vulnerable to symlink attacks because it
uses rename() which follows symbolic links in all path elements but the
rightmost one.

This patch simply transforms local_rename() into a wrapper around
local_renameat() which is symlink-attack safe.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
99f2cf4b2d 9pfs: local: renameat: don't follow symlinks
The local_renameat() callback is currently a wrapper around local_rename()
which is vulnerable to symlink attacks.

This patch rewrites local_renameat() to have its own implementation, based
on local_opendir_nofollow() and renameat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
f9aef99b3e 9pfs: local: lstat: don't follow symlinks
The local_lstat() callback is vulnerable to symlink attacks because it
calls:

(1) lstat() which follows symbolic links in all path elements but the
    rightmost one
(2) getxattr() which follows symbolic links in all path elements
(3) local_mapped_file_attr()->local_fopen()->openat(O_NOFOLLOW) which
    follows symbolic links in all path elements but the rightmost
    one

This patch converts local_lstat() to rely on opendir_nofollow() and
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1), fgetxattrat_nofollow() to
fix (2).

A new local_fopenat() helper is introduced as a replacement to
local_fopen() to fix (3). No effort is made to factor out code
because local_fopen() will be dropped when all users have been
converted to call local_fopenat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
bec1e9546e 9pfs: local: readlink: don't follow symlinks
The local_readlink() callback is vulnerable to symlink attacks because it
calls:

(1) open(O_NOFOLLOW) which follows symbolic links for all path elements but
    the rightmost one
(2) readlink() which follows symbolic links for all path elements but the
    rightmost one

This patch converts local_readlink() to rely on open_nofollow() to fix (1)
and opendir_nofollow(), readlinkat() to fix (2).

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
ac125d993b 9pfs: local: truncate: don't follow symlinks
The local_truncate() callback is vulnerable to symlink attacks because
it calls truncate() which follows symbolic links in all path elements.

This patch converts local_truncate() to rely on open_nofollow() and
ftruncate() instead.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
31e51d1c15 9pfs: local: statfs: don't follow symlinks
The local_statfs() callback is vulnerable to symlink attacks because it
calls statfs() which follows symbolic links in all path elements.

This patch converts local_statfs() to rely on open_nofollow() and fstatfs()
instead.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
a33eda0dd9 9pfs: local: utimensat: don't follow symlinks
The local_utimensat() callback is vulnerable to symlink attacks because it
calls qemu_utimens()->utimensat(AT_SYMLINK_NOFOLLOW) which follows symbolic
links in all path elements but the rightmost one or qemu_utimens()->utimes()
which follows symbolic links for all path elements.

This patch converts local_utimensat() to rely on opendir_nofollow() and
utimensat(AT_SYMLINK_NOFOLLOW) directly instead of using qemu_utimens().
It is hence assumed that the OS supports utimensat(), i.e. has glibc 2.6
or higher and linux 2.6.22 or higher, which seems reasonable nowadays.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
a0e640a872 9pfs: local: remove: don't follow symlinks
The local_remove() callback is vulnerable to symlink attacks because it
calls:

(1) lstat() which follows symbolic links in all path elements but the
    rightmost one
(2) remove() which follows symbolic links in all path elements but the
    rightmost one

This patch converts local_remove() to rely on opendir_nofollow(),
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1) and unlinkat() to fix (2).

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
df4938a665 9pfs: local: unlinkat: don't follow symlinks
The local_unlinkat() callback is vulnerable to symlink attacks because it
calls remove() which follows symbolic links in all path elements but the
rightmost one.

This patch converts local_unlinkat() to rely on opendir_nofollow() and
unlinkat() instead.

Most of the code is moved to a separate local_unlinkat_common() helper
which will be reused in a subsequent patch to fix the same issue in
local_remove().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
72f0d0bf51 9pfs: local: lremovexattr: don't follow symlinks
The local_lremovexattr() callback is vulnerable to symlink attacks because
it calls lremovexattr() which follows symbolic links in all path elements
but the rightmost one.

This patch introduces a helper to emulate the non-existing fremovexattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lremovexattr().

local_lremovexattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
3e36aba757 9pfs: local: lsetxattr: don't follow symlinks
The local_lsetxattr() callback is vulnerable to symlink attacks because
it calls lsetxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing fsetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lsetxattr().

local_lsetxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
5507904e36 9pfs: local: llistxattr: don't follow symlinks
The local_llistxattr() callback is vulnerable to symlink attacks because
it calls llistxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing flistxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to llistxattr().

local_llistxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
56ad3e54da 9pfs: local: lgetxattr: don't follow symlinks
The local_lgetxattr() callback is vulnerable to symlink attacks because
it calls lgetxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing fgetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lgetxattr().

local_lgetxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
996a0d76d7 9pfs: local: open/opendir: don't follow symlinks
The local_open() and local_opendir() callbacks are vulnerable to symlink
attacks because they call:

(1) open(O_NOFOLLOW) which follows symbolic links in all path elements but
    the rightmost one
(2) opendir() which follows symbolic links in all path elements

This patch converts both callbacks to use new helpers based on
openat_nofollow() to only open files and directories if they are
below the virtfs shared folder

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
0e35a37829 9pfs: local: keep a file descriptor on the shared folder
This patch opens the shared folder and caches the file descriptor, so that
it can be used to do symlink-safe path walk.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:15 +01:00
Greg Kurz
6482a96163 9pfs: introduce relative_openat_nofollow() helper
When using the passthrough security mode, symbolic links created by the
guest are actual symbolic links on the host file system.

Since the resolution of symbolic links during path walk is supposed to
occur on the client side. The server should hence never receive any path
pointing to an actual symbolic link. This isn't guaranteed by the protocol
though, and malicious code in the guest can trick the server to issue
various syscalls on paths whose one or more elements are symbolic links.
In the case of the "local" backend using the "passthrough" or "none"
security modes, the guest can directly create symbolic links to arbitrary
locations on the host (as per spec). The "mapped-xattr" and "mapped-file"
security modes are also affected to a lesser extent as they require some
help from an external entity to create actual symbolic links on the host,
i.e. another guest using "passthrough" mode for example.

The current code hence relies on O_NOFOLLOW and "l*()" variants of system
calls. Unfortunately, this only applies to the rightmost path component.
A guest could maliciously replace any component in a trusted path with a
symbolic link. This could allow any guest to escape a virtfs shared folder.

This patch introduces a variant of the openat() syscall that successively
opens each path element with O_NOFOLLOW. When passing a file descriptor
pointing to a trusted directory, one is guaranteed to be returned a
file descriptor pointing to a path which is beneath the trusted directory.
This will be used by subsequent patches to implement symlink-safe path walk
for any access to the backend.

Symbolic links aren't the only threats actually: a malicious guest could
change a path element to point to other types of file with undesirable
effects:
- a named pipe or any other thing that would cause openat() to block
- a terminal device which would become QEMU's controlling terminal

These issues can be addressed with O_NONBLOCK and O_NOCTTY.

Two helpers are introduced: one to open intermediate path elements and one
to open the rightmost path element.

Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
(renamed openat_nofollow() to relative_openat_nofollow(),
 assert path is relative and doesn't contain '//',
 fixed side-effect in assert, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-02-28 11:21:15 +01:00
Greg Kurz
21328e1e57 9pfs: remove side-effects in local_open() and local_opendir()
If these functions fail, they should not change *fs. Let's use local
variables to fix this.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:14 +01:00
Greg Kurz
00c90bd1c2 9pfs: remove side-effects in local_init()
If this function fails, it should not modify *ctx.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:14 +01:00
Greg Kurz
56fc494bdc 9pfs: local: move xattr security ops to 9p-xattr.c
These functions are always called indirectly. It really doesn't make sense
for them to sit in a header file.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-28 11:21:14 +01:00
Pradeep Jagadeesh
b8bbdb886e fsdev: add IO throttle support to fsdev devices
This patchset adds the throttle support for the 9p-local driver.
For now this functionality can be enabled only through qemu cli options.
QMP interface and support to other drivers need further extensions.
To make it simple for other 9p drivers, the throttle code has been put in
separate files.

Signed-off-by: Pradeep Jagadeesh <pradeep.jagadeesh@huawei.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
(pass extra NULL CoMutex * argument to qemu_co_queue_wait(),
 added options to qemu-options.hx, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-02-28 10:31:46 +01:00
Paolo Bonzini
4bae2b397f 9pfs: fix v9fs_lock error case
In this case, we are marshaling an error status instead of the errno value.
Reorganize the out and out_nofid labels to look like all the other cases.
Coverity reports this because the "err = -ENOENT" and "err = -EINVAL"
assignments above are dead, overwritten by the call to pdu_marshal.

(Coverity issues CID1348512 and CID1348513)

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(also open-coded the success path since locking is a nop for us, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-02-28 10:31:46 +01:00
Paolo Bonzini
1ace7ceac5 coroutine-lock: add mutex argument to CoQueue APIs
All that CoQueue needs in order to become thread-safe is help
from an external mutex.  Add this to the API.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-6-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-21 11:39:40 +00:00
Peter Maydell
c7f1cf01b8 This pull request fixes a 2.9 regression and a long standing bug that can
cause 9p clients to hang. Other patches are minor enhancements.
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Merge remote-tracking branch 'remotes/gkurz/tags/for-upstream' into staging

This pull request fixes a 2.9 regression and a long standing bug that can
cause 9p clients to hang. Other patches are minor enhancements.

# gpg: Signature made Wed 25 Jan 2017 10:12:27 GMT
# gpg:                using DSA key 0x02FC3AEB0101DBC2
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg:                 aka "Greg Kurz <groug@free.fr>"
# gpg:                 aka "Greg Kurz <gkurz@fr.ibm.com>"
# gpg:                 aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg:                 aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg:                 aka "Gregory Kurz (Cimai Technology) <gkurz@cimai.com>"
# gpg:                 aka "Gregory Kurz (Meiosys Technology) <gkurz@meiosys.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894  DBA2 02FC 3AEB 0101 DBC2

* remotes/gkurz/tags/for-upstream:
  9pfs: fix offset error in v9fs_xattr_read()
  9pfs: local: trivial cosmetic fix in pwritev op
  9pfs: fix off-by-one error in PDU free list
  tests: virtio-9p: improve error reporting
  9pfs: add missing coroutine_fn annotations

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-01-25 17:54:14 +00:00
Greg Kurz
fa0eb5c512 9pfs: fix offset error in v9fs_xattr_read()
The current code tries to copy `read_count' bytes starting at offset
`offset' from a `read_count`-sized iovec. This causes v9fs_pack() to
fail with ENOBUFS.

Since the PDU iovec is already partially filled with `offset' bytes,
let's skip them when creating `qiov_full' and have v9fs_pack() to
copy the whole of it. Moreover, this is consistent with the other
places where v9fs_init_qiov_from_pdu() is called.

This fixes commit "bcb8998fac16 9pfs: call v9fs_init_qiov_from_pdu
before v9fs_pack".

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
2017-01-25 09:34:35 +01:00
Greg Kurz
6fe76acc2d 9pfs: local: trivial cosmetic fix in pwritev op
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-25 09:34:35 +01:00
Greg Kurz
0d78289c3d 9pfs: fix off-by-one error in PDU free list
The server can handle MAX_REQ - 1 PDUs at a time and the virtio-9p
device has a MAX_REQ sized virtqueue. If the client manages to fill
up the virtqueue, pdu_alloc() will fail and the request won't be
processed without any notice to the client (it actually causes the
linux 9p client to hang).

This has been there since the beginning (commit 9f10751365 "virtio-9p:
Add a virtio 9p device to qemu"), but it needs an agressive workload to
run in the guest to show up.

We actually allocate MAX_REQ PDUs and I see no reason not to link them
all into the free list, so let's fix the init loop.

Reported-by: Tuomas Tynkkynen <tuomas@tuxera.com>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-25 09:34:35 +01:00
Greg Kurz
a1bf8b7414 9pfs: add missing coroutine_fn annotations
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-25 09:34:35 +01:00
Ashijeet Acharya
fe44dc9180 migration: disallow migrate_add_blocker during migration
If a migration is already in progress and somebody attempts
to add a migration blocker, this should rightly fail.

Add an errp parameter and a retcode return value to migrate_add_blocker.

Signed-off-by: John Snow <jsnow@redhat.com>
Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Message-Id: <1484566314-3987-5-git-send-email-ashijeetacharya@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Merged with recent 'Allow invtsc migration' change
2017-01-24 18:00:30 +00:00
Greg Kurz
baecbde6d7 9pfs: fix P9_NOTAG and P9_NOFID macros
The u16 and u32 types don't exist in QEMU common headers. It never broke
build because these two macros aren't use by the current code, but this
is about to change with the future addition of functional tests for 9P.

Also, these should have enclosing parenthesis to be usable in any
syntactical situation.

As suggested by Eric Blake, let's use UINT16_MAX and UINT32_MAX to address
both issues.

Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-03 17:28:44 +01:00
Greg Kurz
f2b58c4375 9pfs: fix crash when fsdev is missing
If the user passes -device virtio-9p without the corresponding -fsdev, QEMU
dereferences a NULL pointer and crashes.

This is a 2.8 regression introduced by commit 702dbcc274.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Li Qiang <liq3ea@gmail.com>
2017-01-03 17:28:44 +01:00
Stefano Stabellini
88da0b0301 9pfs: introduce init_out/in_iov_from_pdu
Not all 9pfs transports share memory between request and response. For
those who don't, it is necessary to know how much memory is required in
the response.

Split the existing init_iov_from_pdu function in two:
init_out_iov_from_pdu (for writes) and init_in_iov_from_pdu (for reads).
init_in_iov_from_pdu takes an additional size parameter to specify the
memory required for the response message.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-03 17:28:44 +01:00
Stefano Stabellini
bcb8998fac 9pfs: call v9fs_init_qiov_from_pdu before v9fs_pack
v9fs_xattr_read should not access VirtQueueElement elems directly.
Move v9fs_init_qiov_from_pdu up in the file and call
v9fs_init_qiov_from_pdu before v9fs_pack. Use v9fs_pack on the new
iovec.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-03 17:28:44 +01:00
Stefano Stabellini
ea83441cc4 9pfs: introduce transport specific callbacks
Don't call virtio functions from 9pfs generic code, use generic function
callbacks instead.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-03 17:28:44 +01:00
Stefano Stabellini
583f21f8b9 9pfs: move pdus to V9fsState
pdus are initialized and used in 9pfs common code. Move the array from
V9fsVirtioState to V9fsState.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2017-01-03 17:28:44 +01:00
Li Qiang
898ae90a44 9pfs: add cleanup operation for proxy backend driver
In the init operation of proxy backend dirver, it allocates a
V9fsProxy struct and some other resources. We should free these
resources when the 9pfs device is unrealized. This is what this
patch does.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-23 13:53:34 +01:00
Li Qiang
971f406b77 9pfs: add cleanup operation for handle backend driver
In the init operation of handle backend dirver, it allocates a
handle_data struct and opens a mount file. We should free these
resources when the 9pfs device is unrealized. This is what this
patch does.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-23 13:53:34 +01:00
Li Qiang
702dbcc274 9pfs: add cleanup operation in FileOperations
Currently, the backend of VirtFS doesn't have a cleanup
function. This will lead resource leak issues if the backed
driver allocates resources. This patch addresses this issue.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-23 13:53:34 +01:00
Li Qiang
4774718e5c 9pfs: adjust the order of resource cleanup in device unrealize
Unrealize should undo things that were set during realize in
reverse order. So should do in the error path in realize.

Signed-off-by: Li Qiang <liq3ea@gmail.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-23 13:53:34 +01:00
Greg Kurz
79decce35b 9pfs: drop excessive error message from virtfs_reset()
The virtfs_reset() function is called either when the virtio-9p device
gets reset, or when the client starts a new 9P session. In both cases,
if it finds fids from a previous session, the following is printed in
the monitor:

9pfs:virtfs_reset: One or more uncluncked fids found during reset

For example, if a linux guest with a mounted 9P share is reset from the
monitor with system_reset, the message will be printed. This is excessive
since these fids are now clunked and the state is clean.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
2016-11-01 12:03:03 +01:00
Greg Kurz
49dd946bb5 9pfs: don't BUG_ON() if fid is already opened
A buggy or malicious guest could pass the id of an already opened fid and
cause QEMU to abort. Let's return EINVAL to the guest instead.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
2016-11-01 12:03:02 +01:00
Greg Kurz
dd654e0365 9pfs: xattrcreate requires non-opened fids
The xattrcreate operation only makes sense on a freshly cloned fid
actually, since any open state would be leaked because of the fid_type
change. This is indeed what the linux kernel client does:

	fid = clone_fid(fid);
	[...]
	retval = p9_client_xattrcreate(fid, name, value_len, flags);

This patch also reverts commit ff55e94d23 since we are sure that a fid
with type P9_FID_NONE doesn't have a previously allocated xattr.

Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-01 12:03:02 +01:00
Greg Kurz
3b79ef2cf4 9pfs: limit xattr size in xattrcreate
We shouldn't allow guests to create extended attribute with arbitrary sizes.
On linux hosts, the limit is XATTR_SIZE_MAX. Let's use it.

Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-01 12:03:02 +01:00
Li Qiang
7e55d65c56 9pfs: fix integer overflow issue in xattr read/write
The v9fs_xattr_read() and v9fs_xattr_write() are passed a guest
originated offset: they must ensure this offset does not go beyond
the size of the extended attribute that was set in v9fs_xattrcreate().
Unfortunately, the current code implement these checks with unsafe
calculations on 32 and 64 bit values, which may allow a malicious
guest to cause OOB access anyway.

Fix this by comparing the offset and the xattr size, which are
both uint64_t, before trying to compute the effective number of bytes
to read or write.

Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-By: Guido Günther <agx@sigxcpu.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-01 12:03:01 +01:00
Li Qiang
8495f9ad26 9pfs: convert 'len/copied_len' field in V9fsXattr to the type of uint64_t
The 'len' in V9fsXattr comes from the 'size' argument in setxattr()
function in guest. The setxattr() function's declaration is this:

int setxattr(const char *path, const char *name,
             const void *value, size_t size, int flags);

and 'size' is treated as u64 in linux kernel client code:

int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
                          u64 attr_size, int flags)

So the 'len' should have an type of 'uint64_t'.
The 'copied_len' in V9fsXattr is used to account for copied bytes, it
should also have an type of 'uint64_t'.

Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-01 12:03:01 +01:00
Li Qiang
dd28fbbc2e 9pfs: add xattrwalk_fid field in V9fsXattr struct
Currently, 9pfs sets the 'copied_len' field in V9fsXattr
to -1 to tag xattr walk fid. As the 'copied_len' is also
used to account for copied bytes, this may make confusion. This patch
add a bool 'xattrwalk_fid' to tag the xattr walk fid.

Suggested-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-11-01 12:00:40 +01:00
Li Qiang
fdfcc9aeea 9pfs: fix memory leak in v9fs_write
If an error occurs when marshalling the transfer length to the guest, the
v9fs_write() function doesn't free an IO vector, thus leading to a memory
leak. This patch fixes the issue.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, rephrased the changelog]
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Li Qiang
4c1586787f 9pfs: fix memory leak in v9fs_link
The v9fs_link() function keeps a reference on the source fid object. This
causes a memory leak since the reference never goes down to 0. This patch
fixes the issue.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, rephrased the changelog]
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Li Qiang
ff55e94d23 9pfs: fix memory leak in v9fs_xattrcreate
The 'fs.xattr.value' field in V9fsFidState object doesn't consider the
situation that this field has been allocated previously. Every time, it
will be allocated directly. This leads to a host memory leak issue if
the client sends another Txattrcreate message with the same fid number
before the fid from the previous time got clunked.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
[groug, updated the changelog to indicate how the leak can occur]
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Li Qiang
eb68760285 9pfs: fix information leak in xattr read
9pfs uses g_malloc() to allocate the xattr memory space, if the guest
reads this memory before writing to it, this will leak host heap memory
to the guest. This patch avoid this.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Greg Kurz
0e44a0fd3f virtio-9p: add reset handler
Virtio devices should implement the VirtIODevice->reset() function to
perform necessary cleanup actions and to bring the device to a quiescent
state.

In the case of the virtio-9p device, this means:
- emptying the list of active PDUs (i.e. draining all in-flight I/O)
- freeing all fids (i.e. close open file descriptors and free memory)

That's what this patch does.

The reset handler first waits for all active PDUs to complete. Since
completion happens in the QEMU global aio context, we just have to
loop around aio_poll() until the active list is empty.

The freeing part involves some actions to be performed on the backend,
like closing file descriptors or flushing extended attributes to the
underlying filesystem. The virtfs_reset() function already does the
job: it calls free_fid() for all open fids not involved in an ongoing
I/O operation. We are sure this is the case since we have drained
the PDU active list.

The current code implements all backend accesses with coroutines, but we
want to stay synchronous on the reset path. We can either change the
current code to be able to run when not in coroutine context, or create
a coroutine context and wait for virtfs_reset() to complete. This patch
goes for the latter because it results in simpler code.

Note that we also need to create a dummy PDU because it is also an API
to pass the FsContext pointer to all backend callbacks.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-17 14:13:58 +02:00
Greg Kurz
f74e27bf0f 9pfs: only free completed request if not flushed
If a PDU has a flush request pending, the current code calls pdu_free()
twice:

1) pdu_complete()->pdu_free() with pdu->cancelled set, which does nothing

2) v9fs_flush()->pdu_free() with pdu->cancelled cleared, which moves the
   PDU back to the free list.

This works but it complexifies the logic of pdu_free().

With this patch, pdu_complete() only calls pdu_free() if no flush request
is pending, i.e. qemu_co_queue_next() returns false.

Since pdu_free() is now supposed to be called with pdu->cancelled cleared,
the check in pdu_free() is dropped and replaced by an assertion.

Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Greg Kurz
6868a420c5 9pfs: drop useless check in pdu_free()
Out of the three users of pdu_free(), none ever passes a NULL pointer to
this function.

Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Greg Kurz
8440e22ec1 9pfs: use coroutine_fn annotation in hw/9pfs/9p.[ch]
All these functions either call the v9fs_co_* functions which have the
coroutine_fn annotation, or pdu_complete() which calls qemu_co_queue_next().

Let's mark them to make it obvious they execute in coroutine context.

Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Greg Kurz
5bdade6621 9pfs: use coroutine_fn annotation in hw/9pfs/co*.[ch]
All these functions use the v9fs_co_run_in_worker() macro, and thus always
call qemu_coroutine_self() and qemu_coroutine_yield().

Let's mark them to make it obvious they execute in coroutine context.

Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Greg Kurz
bc70a5925f 9pfs: fsdev: drop useless extern annotation for functions
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Li Qiang
e95c9a493a 9pfs: fix potential host memory leak in v9fs_read
In 9pfs read dispatch function, it doesn't free two QEMUIOVector
object thus causing potential memory leak. This patch avoid this.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Li Qiang
ba42ebb863 9pfs: allocate space for guest originated empty strings
If a guest sends an empty string paramater to any 9P operation, the current
code unmarshals it into a V9fsString equal to { .size = 0, .data = NULL }.

This is unfortunate because it can cause NULL pointer dereference to happen
at various locations in the 9pfs code. And we don't want to check str->data
everywhere we pass it to strcmp() or any other function which expects a
dereferenceable pointer.

This patch enforces the allocation of genuine C empty strings instead, so
callers don't have to bother.

Out of all v9fs_iov_vunmarshal() users, only v9fs_xattrwalk() checks if
the returned string is empty. It now uses v9fs_string_size() since
name.data cannot be NULL anymore.

Signed-off-by: Li Qiang <liqiang6-s@360.cn>
[groug, rewritten title and changelog,
 fix empty string check in v9fs_xattrwalk()]
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-10-17 14:13:58 +02:00
Halil Pasic
5705653ff8 virtio: cleanup VMSTATE_VIRTIO_DEVICE
Now all the usages of the old version of VMSTATE_VIRTIO_DEVICE are gone,
so we can get rid of the conditionals, and the old macro.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-10 02:21:43 +03:00
Halil Pasic
dcaf8dda4b virtio-9p: convert VMSTATE_VIRTIO_DEVICE
Use the new VMSTATE_VIRTIO_DEVICE macro.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-10 02:21:42 +03:00
Greg Kurz
d3d74d6fe0 virtio-9p: handle handle_9p_output() error
A broken guest may send a request without providing buffers for the reply
or for the request itself, and virtqueue_pop() will return an element with
either in_num == 0 or out_num == 0.

All 9P requests are expected to start with the following 7-byte header:

            uint32_t size_le;
            uint8_t id;
            uint16_t tag_le;

If iov_to_buf() fails to return these 7 bytes, then something is wrong in
the guest.

In both cases, it is wrong to crash QEMU, since the root cause lies in the
guest.

This patch hence does the following:
- keep the check of in_num since pdu_complete() assumes it has enough
  space to store the reply and we will send something broken to the guest
- let iov_to_buf() handle out_num == 0, since it will return 0 just like
  if the guest had provided an zero-sized buffer.
- call virtio_error() to inform the guest that the device is now broken,
  instead of aborting
- detach the request from the virtqueue and free it

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-10 01:16:59 +03:00
Greg Kurz
e8582891cb virtio-9p: add parentheses to sizeof operator
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-10-10 01:16:58 +03:00
Greg Kurz
13fd08e631 9pfs: fix potential segfault during walk
If the call to fid_to_qid() returns an error, we will call v9fs_path_free()
on uninitialized paths.

It is a regression introduced by the following commit:

56f101ecce 9pfs: handle walk of ".." in the root directory

Let's fix this by initializing dpath and path before calling fid_to_qid().

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
[groug: updated the changelog to indicate this is regression and to provide
        the offending commit SHA1]
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-09-19 11:39:48 +02:00
Greg Kurz
e3e83f2e21 9pfs: introduce v9fs_path_sprintf() helper
This helper is similar to v9fs_string_sprintf(), but it includes the
terminating NUL character in the size field.

This is to avoid doing v9fs_string_sprintf((V9fsString *) &path) and
then bumping the size.

Affected users are changed to use this new helper.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
2016-09-16 08:56:15 +02:00
Greg Kurz
abdf008640 9pfs: drop useless v9fs_string_null() function
The v9fs_string_null() function just calls v9fs_string_free(). Also it
only has 4 users, whereas v9fs_string_free() has 87.

This patch converts users to call directly v9fs_string_free() and drops
the useless function.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
2016-09-16 08:56:15 +02:00
Greg Kurz
da4bc86c54 9pfs: drop duplicate line in proxy backend
This double free did not cause harm because v9fs_string_free() sets
str->data to NULL and g_free(NULL) is valid.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
2016-09-16 08:56:14 +02:00
Greg Kurz
799fe087e4 9pfs: drop unused fmt strings in the proxy backend
The v9fs_request() function doesn't use its fmt argument: it passes literal
format strings to proxy_marshal() for all commands.

This patch simply drops the unused fmt argument and updates all callers
accordingly.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
2016-09-16 08:56:14 +02:00
Greg Kurz
56f101ecce 9pfs: handle walk of ".." in the root directory
The 9P spec at http://man.cat-v.org/plan_9/5/intro says:

All directories must support walks to the directory .. (dot-dot) meaning
parent directory, although by convention directories contain no explicit
entry for .. or . (dot).  The parent of the root directory of a server's
tree is itself.

This means that a client cannot walk further than the root directory
exported by the server. In other words, if the client wants to walk
"/.." or "/foo/../..", the server should answer like the request was
to walk "/".

This patch just does that:
- we cache the QID of the root directory at attach time
- during the walk we compare the QID of each path component with the root
  QID to detect if we're in a "/.." situation
- if so, we skip the current component and go to the next one

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-08-30 19:23:00 +01:00
Greg Kurz
805b5d98c6 9pfs: forbid . and .. in file names
According to the 9P spec http://man.cat-v.org/plan_9/5/open about the
create request:

The names . and .. are special; it is illegal to create files with these
names.

This patch causes the create and lcreate requests to fail with EINVAL if
the file name is either "." or "..".

Even if it isn't explicitly written in the spec, this patch extends the
checking to all requests that may cause a directory entry to be created:

    - mknod
    - rename
    - renameat
    - mkdir
    - link
    - symlink

The unlinkat request also gets patched for consistency (even if
rmdir("foo/..") is expected to fail according to POSIX.1-2001).

The various error values come from the linux manual pages.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-08-30 19:21:56 +01:00
Greg Kurz
fff39a7ad0 9pfs: forbid illegal path names
Empty path components don't make sense for most commands and may cause
undefined behavior, depending on the backend.

Also, the walk request described in the 9P spec [1] clearly shows that
the client is supposed to send individual path components: the official
linux client never sends portions of path containing the / character for
example.

Moreover, the 9P spec [2] also states that a system can decide to restrict
the set of supported characters used in path components, with an explicit
mention "to remove slashes from name components".

This patch introduces a new name_is_illegal() helper that checks the
names sent by the client are not empty and don't contain unwanted chars.
Since 9pfs is only supported on linux hosts, only the / character is
checked at the moment. When support for other hosts (AKA. win32) is added,
other chars may need to be blacklisted as well.

If a client sends an illegal path component, the request will fail and
ENOENT is returned to the client.

[1] http://man.cat-v.org/plan_9/5/walk
[2] http://man.cat-v.org/plan_9/5/intro

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-08-30 19:21:39 +01:00
Laurent Vivier
e723b87103 trace-events: fix first line comment in trace-events
Documentation is docs/tracing.txt instead of docs/trace-events.txt.

find . -name trace-events -exec \
     sed -i "s?See docs/trace-events.txt for syntax documentation.?See docs/tracing.txt for syntax documentation.?" \
     {} \;

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-id: 1470669081-17860-1-git-send-email-lvivier@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-08-12 10:36:01 +01:00
Dr. David Alan Gilbert
18e0e5b240 9pfs: Wrap in vmstate
Forcibly convert it to a vmstate wrapper;  proper conversion
comes later.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2016-07-21 20:44:20 +03:00
Paolo Bonzini
0b8b8753e4 coroutine: move entry argument to qemu_coroutine_create
In practice the entry argument is always known at creation time, and
it is confusing that sometimes qemu_coroutine_enter is used with a
non-NULL argument to re-enter a coroutine (this happens in
block/sheepdog.c and tests/test-coroutine.c).  So pass the opaque value
at creation time, for consistency with e.g. aio_bh_new.

Mostly done with the following semantic patch:

@ entry1 @
expression entry, arg, co;
@@
- co = qemu_coroutine_create(entry);
+ co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry2 @
expression entry, arg;
identifier co;
@@
- Coroutine *co = qemu_coroutine_create(entry);
+ Coroutine *co = qemu_coroutine_create(entry, arg);
  ...
- qemu_coroutine_enter(co, arg);
+ qemu_coroutine_enter(co);

@ entry3 @
expression entry, arg;
@@
- qemu_coroutine_enter(qemu_coroutine_create(entry), arg);
+ qemu_coroutine_enter(qemu_coroutine_create(entry, arg));

@ reentry @
expression co;
@@
- qemu_coroutine_enter(co, NULL);
+ qemu_coroutine_enter(co);

except for the aforementioned few places where the semantic patch
stumbled (as expected) and for test_co_queue, which would otherwise
produce an uninitialized variable warning.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2016-07-13 13:26:02 +02:00
Markus Armbruster
2a6a4076e1 Clean up ill-advised or unusual header guards
Cleaned up with scripts/clean-header-guards.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-12 16:20:46 +02:00
Markus Armbruster
121d07125b Clean up header guards that don't match their file name
Header guard symbols should match their file name to make guard
collisions less likely.  Offenders found with
scripts/clean-header-guards.pl -vn.

Cleaned up with scripts/clean-header-guards.pl, followed by some
renaming of new guard symbols picked by the script to better ones.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
2016-07-12 16:19:16 +02:00
Greg Kurz
b05528b533 9p: synth: drop v9fs_ prefix
To have shorter lines and be consistent with other fs devices.

Acked-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
2016-07-01 14:38:54 +02:00
Daniel P. Berrange
d018a2e931 trace: split out trace events for hw/9pfs/ directory
Move all trace-events for files in the hw/9pfs/ directory to
their own file.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1466066426-16657-26-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-06-20 17:22:16 +01:00