[RFC PATCH ghak9 3/3] [WIP] fs: Add audit_fd_path() calls to syscall handlers

[Ondrej Mosnacek <omosnace@redhat.com>]

So far only add one to openat(2) for testing purposes.

Example records:
type=PROCTITLE msg=audit(07/04/18 15:28:41.808:76) : proctitle=/bin/bash ./openat-audit-test.sh
type=PATH msg=audit(07/04/18 15:28:41.808:76) : item=0 name=b inode=2154 dev=00:1a mode=dir,755 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:tmpfs_t:s0 nametype=NORMAL cap_fp=none cap_fi=none cap_fe=0 cap_fver=0
type=CWD msg=audit(07/04/18 15:28:41.808:76) : cwd=/root/Dokumenty/Kernel
type=SYSCALL msg=audit(07/04/18 15:28:41.808:76) : arch=x86_64 syscall=openat success=yes exit=6 a0=0x5 a1=0x55bad2616348 a2=O_RDONLY|O_NOCTTY|O_NONBLOCK|O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC a3=0x0 items=1 ppid=594 pid=630 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=1 comm=find exe=/usr/bin/find subj=system_u:system_r:kernel_t:s0 key=(null)
type=FD_PATH msg=audit(07/04/18 15:28:41.808:76) : fd=5 path=/tmp/a
----
type=PROCTITLE msg=audit(07/04/18 15:28:41.808:77) : proctitle=/bin/bash ./openat-audit-test.sh
type=PATH msg=audit(07/04/18 15:28:41.808:77) : item=0 name=c inode=2155 dev=00:1a mode=dir,755 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:tmpfs_t:s0 nametype=NORMAL cap_fp=none cap_fi=none cap_fe=0 cap_fver=0
type=CWD msg=audit(07/04/18 15:28:41.808:77) : cwd=/root/Dokumenty/Kernel
type=SYSCALL msg=audit(07/04/18 15:28:41.808:77) : arch=x86_64 syscall=openat success=yes exit=6 a0=0x7 a1=0x55bad260e328 a2=O_RDONLY|O_NOCTTY|O_NONBLOCK|O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC a3=0x0 items=1 ppid=594 pid=630 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=1 comm=find exe=/usr/bin/find subj=system_u:system_r:kernel_t:s0 key=(null)
type=FD_PATH msg=audit(07/04/18 15:28:41.808:77) : fd=7 path=/tmp/a/b
----

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 fs/open.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/open.c b/fs/open.c
index d0e955b558ad..7fa326fc025d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1125,6 +1125,8 @@ SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
 	if (force_o_largefile())
 		flags |= O_LARGEFILE;
 
+	audit_fd_path(dfd);
+
 	return do_sys_open(dfd, filename, flags, mode);
 }
 
-- 
2.17.1