Re: [PATCH v4 3/3] audit: add OPENAT2 record to list how

[Paul Moore]

On Wed, May 19, 2021 at 4:02 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
>
> Since the openat2(2) syscall uses a struct open_how pointer to communicate
> its parameters they are not usefully recorded by the audit SYSCALL record's
> four existing arguments.
>
> Add a new audit record type OPENAT2 that reports the parameters in its
> third argument, struct open_how with fields oflag, mode and resolve.
>
> The new record in the context of an event would look like:
> time->Wed Mar 17 16:28:53 2021
> type=PROCTITLE msg=audit(1616012933.531:184): proctitle=73797363616C6C735F66696C652F6F70656E617432002F746D702F61756469742D7465737473756974652D737641440066696C652D6F70656E617432
> type=PATH msg=audit(1616012933.531:184): item=1 name="file-openat2" inode=29 dev=00:1f mode=0100600 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> type=PATH msg=audit(1616012933.531:184): item=0 name="/root/rgb/git/audit-testsuite/tests" inode=25 dev=00:1f mode=040700 ouid=0 ogid=0 rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=PARENT cap_fp=0 cap_fi=0 cap_fe=0 cap_fver=0 cap_frootid=0
> type=CWD msg=audit(1616012933.531:184): cwd="/root/rgb/git/audit-testsuite/tests"
> type=OPENAT2 msg=audit(1616012933.531:184): oflag=0100302 mode=0600 resolve=0xa
> type=SYSCALL msg=audit(1616012933.531:184): arch=c000003e syscall=437 success=yes exit=4 a0=3 a1=7ffe315f1c53 a2=7ffe315f1550 a3=18 items=2 ppid=528 pid=540 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 ses=1 comm="openat2" exe="/root/rgb/git/audit-testsuite/tests/syscalls_file/openat2" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key="testsuite-1616012933-bjAUcEPO"
>
> Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> Link: https://lore.kernel.org/r/d23fbb89186754487850367224b060e26f9b7181.1621363275.git.rgb@xxxxxxxxxx
> ---
>  fs/open.c                  |  2 ++
>  include/linux/audit.h      | 10 ++++++++++
>  include/uapi/linux/audit.h |  1 +
>  kernel/audit.h             |  2 ++
>  kernel/auditsc.c           | 18 +++++++++++++++++-
>  5 files changed, 32 insertions(+), 1 deletion(-)

...

> diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> index cd2d8279a5e4..67aea2370c6d 100644
> --- a/include/uapi/linux/audit.h
> +++ b/include/uapi/linux/audit.h
> @@ -118,6 +118,7 @@
>  #define AUDIT_TIME_ADJNTPVAL   1333    /* NTP value adjustment */
>  #define AUDIT_BPF              1334    /* BPF subsystem */
>  #define AUDIT_EVENT_LISTENER   1335    /* Task joined multicast read socket */
> +#define AUDIT_OPENAT2          1336    /* Record showing openat2 how args */

As a heads-up, I had to change the AUDIT_OPENAT2 value to 1337 as the
1336 value is already in use by AUDIT_URINGOP.  It wasn't caught
during my initial build test as the LSM/audit io_uring patches are in
selinux/next and not audit/next, it wasn't until the kernel-secnext
build was merging everything for its test run that the collision
occurred.  I'll be updating the audit/next tree with the new value
shortly.

-- 
paul moore
www.paul-moore.com