Commit 893c47d1 authored Jul 14, 2021 by Austin Kim Committed by Paul Moore Jul 14, 2021

selinux: return early for possible NULL audit buffers



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.

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

So add exception handling for possible NULL audit buffers where
return value can be handled from callers.

Signed-off-by: Austin Kim <austin.kim@lge.com>
[PM: tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>

parent e73f0f0e

security/selinux/hooks.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -3325,6 +3325,8 @@ static int selinux_inode_setxattr(struct user_namespace *mnt_userns,
		}
		ab = audit_log_start(audit_context(),
		GFP_ATOMIC, AUDIT_SELINUX_ERR);
		if (!ab)
		return rc;
		audit_log_format(ab, "op=setxattr invalid_context=");
		audit_log_n_untrustedstring(ab, value, audit_size);
		audit_log_end(ab);
		@@ -6552,6 +6554,8 @@ static int selinux_setprocattr(const char name, void value, size_t size)
		ab = audit_log_start(audit_context(),
		GFP_ATOMIC,
		AUDIT_SELINUX_ERR);
		if (!ab)
		return error;
		audit_log_format(ab, "op=fscreate invalid_context=");
		audit_log_n_untrustedstring(ab, value, audit_size);
		audit_log_end(ab);

security/selinux/ss/services.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1673,6 +1673,8 @@ static int compute_sid_handle_invalid_context(
		if (context_struct_to_string(policydb, newcontext, &n, &nlen))
		goto out;
		ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_SELINUX_ERR);
		if (!ab)
		goto out;
		audit_log_format(ab,
		"op=security_compute_sid invalid_context=");
		/* no need to record the NUL with untrusted strings */