Commit Graph

11 Commits

Author SHA1 Message Date
Masahiro Yamada dccd3ab55e bpfilter: re-add header search paths to tools include to fix build error
I thought header search paths to tools/include(/uapi) were unneeded,
but it looks like a build error occurs depending on the compiler.

Commit 303a339f30 ("bpfilter: remove extra header search paths for
bpfilter_umh") reintroduced the build error fixed by commit ae40832e53
("bpfilter: fix a build err").

Apology for the breakage, and thanks to Guenter for reporting this.

Fixes: 303a339f30 ("bpfilter: remove extra header search paths for bpfilter_umh")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-23 13:34:40 -08:00
Masahiro Yamada 303a339f30 bpfilter: remove extra header search paths for bpfilter_umh
Currently, the header search paths -Itools/include and
-Itools/include/uapi are not used. Let's drop the unused code.

We can remove -I. too by fixing up one C file.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-03 20:11:43 -08:00
Laura Abbott b90a368000 kbuild: Rename HOSTLDFLAGS to KBUILD_HOSTLDFLAGS
In preparation for enabling command line LDFLAGS, re-name HOSTLDFLAGS
to KBUILD_HOSTLDFLAGS as the internal use only flags. This should not
have any visible effects.

Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-18 01:18:05 +09:00
Laura Abbott 96f14fe738 kbuild: Rename HOSTCFLAGS to KBUILD_HOSTCFLAGS
In preparation for enabling command line CFLAGS, re-name HOSTCFLAGS to
KBUILD_HOSTCFLAGS as the internal use only flags. This should not have
any visible effects.

Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-18 01:18:05 +09:00
Masahiro Yamada 8e75887d32 bpfilter: include bpfilter_umh in assembly instead of using objcopy
What we want here is to embed a user-space program into the kernel.
Instead of the complex ELF magic, let's simply wrap it in the assembly
with the '.incbin' directive.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-28 21:39:16 +09:00
Matteo Croce c24fb5e68e bpfilter: fix user mode helper cross compilation
Use $(OBJDUMP) instead of literal 'objdump' to avoid
using host toolchain when cross compiling.

Fixes: 421780fd49 ("bpfilter: fix build error")
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Reported-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-21 09:19:19 +09:00
Matteo Croce 421780fd49 bpfilter: fix build error
bpfilter Makefile assumes that the system locale is en_US, and the
parsing of objdump output fails.
Set LC_ALL=C and, while at it, rewrite the objdump parsing so it spawns
only 2 processes instead of 7.

Fixes: d2ba09c17a ("net: add skeleton of bpfilter kernel module")
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-20 09:07:46 +09:00
Alexei Starovoitov 8d97ca6b67 bpfilter: fix OUTPUT_FORMAT
CONFIG_OUTPUT_FORMAT is x86 only macro.
Used objdump to extract elf file format.

Fixes: d2ba09c17a ("net: add skeleton of bpfilter kernel module")
Reported-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-07 16:56:48 -04:00
Alexei Starovoitov 819dd92b9c bpfilter: switch to CC from HOSTCC
check that CC can build executables and use that compiler instead of HOSTCC

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-05 10:21:18 -04:00
YueHaibing ae40832e53 bpfilter: fix a build err
gcc-7.3.0 report following err:

  HOSTCC  net/bpfilter/main.o
In file included from net/bpfilter/main.c:9:0:
./include/uapi/linux/bpf.h:12:10: fatal error: linux/bpf_common.h: No such file or directory
 #include <linux/bpf_common.h>

remove it by adding a include path.
Fixes: d2ba09c17a ("net: add skeleton of bpfilter kernel module")

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-29 15:20:21 -04:00
Alexei Starovoitov d2ba09c17a net: add skeleton of bpfilter kernel module
bpfilter.ko consists of bpfilter_kern.c (normal kernel module code)
and user mode helper code that is embedded into bpfilter.ko

The steps to build bpfilter.ko are the following:
- main.c is compiled by HOSTCC into the bpfilter_umh elf executable file
- with quite a bit of objcopy and Makefile magic the bpfilter_umh elf file
  is converted into bpfilter_umh.o object file
  with _binary_net_bpfilter_bpfilter_umh_start and _end symbols
  Example:
  $ nm ./bld_x64/net/bpfilter/bpfilter_umh.o
  0000000000004cf8 T _binary_net_bpfilter_bpfilter_umh_end
  0000000000004cf8 A _binary_net_bpfilter_bpfilter_umh_size
  0000000000000000 T _binary_net_bpfilter_bpfilter_umh_start
- bpfilter_umh.o and bpfilter_kern.o are linked together into bpfilter.ko

bpfilter_kern.c is a normal kernel module code that calls
the fork_usermode_blob() helper to execute part of its own data
as a user mode process.

Notice that _binary_net_bpfilter_bpfilter_umh_start - end
is placed into .init.rodata section, so it's freed as soon as __init
function of bpfilter.ko is finished.
As part of __init the bpfilter.ko does first request/reply action
via two unix pipe provided by fork_usermode_blob() helper to
make sure that umh is healthy. If not it will kill it via pid.

Later bpfilter_process_sockopt() will be called from bpfilter hooks
in get/setsockopt() to pass iptable commands into umh via bpfilter.ko

If admin does 'rmmod bpfilter' the __exit code bpfilter.ko will
kill umh as well.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-23 13:23:40 -04:00