evm: properly handle INTEGRITY_NOXATTRS EVM status
commit 3dcbad52cf
upstream.
Unless an LSM labels a file during d_instantiate(), newly created
files are not labeled with an initial security.evm xattr, until
the file closes. EVM, before allowing a protected, security xattr
to be written, verifies the existing 'security.evm' value is good.
For newly created files without a security.evm label, this
verification prevents writing any protected, security xattrs,
until the file closes.
Following is the example when this happens:
fd = open("foo", O_CREAT | O_WRONLY, 0644);
setxattr("foo", "security.SMACK64", value, sizeof(value), 0);
close(fd);
While INTEGRITY_NOXATTRS status is handled in other places, such
as evm_inode_setattr(), it does not handle it in all cases in
evm_protect_xattr(). By limiting the use of INTEGRITY_NOXATTRS to
newly created files, we can now allow setting "protected" xattrs.
Changelog:
- limit the use of INTEGRITY_NOXATTRS to IMA identified new files
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
7f4ec7741d
commit
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@ -269,6 +269,13 @@ static int evm_protect_xattr(struct dentry *dentry, const char *xattr_name,
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goto out;
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}
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evm_status = evm_verify_current_integrity(dentry);
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if (evm_status == INTEGRITY_NOXATTRS) {
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struct integrity_iint_cache *iint;
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iint = integrity_iint_find(dentry->d_inode);
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if (iint && (iint->flags & IMA_NEW_FILE))
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return 0;
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}
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out:
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if (evm_status != INTEGRITY_PASS)
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integrity_audit_msg(AUDIT_INTEGRITY_METADATA, dentry->d_inode,
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