2021-10-09 06:32:13

by Gaosheng Cui

Subject: [PATCH -next] integrity: return early if audit_log_start return NULL

audit_log_start() may return NULL in below cases:
- when audit is not initialized.
- when audit backlog limit exceeds.

After the call to audit_log_start() is made and then possible NULL audit
buffer argument is passed to audit_log_*() functions, audit_log_*()
functions return immediately in case of a NULL audit buffer argument.

It is not necessary for audit_log_*() functions to be called with
NULL audit buffer argument, so return early when audit_log_start()
returns NULL.

Signed-off-by: Gaosheng Cui <[email protected]>
---
security/integrity/integrity_audit.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
index 29220056207f..fbc032185d72 100644
--- a/security/integrity/integrity_audit.c
+++ b/security/integrity/integrity_audit.c
@@ -45,6 +45,8 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
return;

ab = audit_log_start(audit_context(), GFP_KERNEL, audit_msgno);
+ if (unlikely(!ab))
+ return;
audit_log_format(ab, "pid=%d uid=%u auid=%u ses=%u",
task_pid_nr(current),
from_kuid(&init_user_ns, current_uid()),
--
2.30.0

2021-10-12 14:17:54

by Paul Moore

Subject: Re: [PATCH -next] integrity: return early if audit_log_start return NULL

On Sat, Oct 9, 2021 at 2:28 AM Gaosheng Cui <[email protected]> wrote:
>
> audit_log_start() may return NULL in below cases:
> - when audit is not initialized.
> - when audit backlog limit exceeds.
>
> After the call to audit_log_start() is made and then possible NULL audit
> buffer argument is passed to audit_log_*() functions, audit_log_*()
> functions return immediately in case of a NULL audit buffer argument.
>
> It is not necessary for audit_log_*() functions to be called with
> NULL audit buffer argument, so return early when audit_log_start()
> returns NULL.
>
> Signed-off-by: Gaosheng Cui <[email protected]>
> ---
> security/integrity/integrity_audit.c | 2 ++
> 1 file changed, 2 insertions(+)

Acked-by: Paul Moore <[email protected]>

> diff --git a/security/integrity/integrity_audit.c b/security/integrity/integrity_audit.c
> index 29220056207f..fbc032185d72 100644
> --- a/security/integrity/integrity_audit.c
> +++ b/security/integrity/integrity_audit.c
> @@ -45,6 +45,8 @@ void integrity_audit_message(int audit_msgno, struct inode *inode,
> return;
>
> ab = audit_log_start(audit_context(), GFP_KERNEL, audit_msgno);
> + if (unlikely(!ab))
> + return;
> audit_log_format(ab, "pid=%d uid=%u auid=%u ses=%u",
> task_pid_nr(current),
> from_kuid(&init_user_ns, current_uid()),
> --
> 2.30.0

--
paul moore
http://www.paul-moore.com