Commit 763dafc5 authored Apr 20, 2020 by Paul Moore

audit: check the length of userspace generated audit records



Commit 75612528 ("audit: always check the netlink payload length
in audit_receive_msg()") fixed a number of missing message length
checks, but forgot to check the length of userspace generated audit
records.  The good news is that you need CAP_AUDIT_WRITE to submit
userspace audit records, which is generally only given to trusted
processes, so the impact should be limited.

Cc: stable@vger.kernel.org
Fixes: 75612528 ("audit: always check the netlink payload length in audit_receive_msg()")
Reported-by:  <syzbot+49e69b4d71a420ceda3e@syzkaller.appspotmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

parent ae83d0b4

kernel/audit.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1326,6 +1326,9 @@ static int audit_receive_msg(struct sk_buff skb, struct nlmsghdr nlh)
		case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
		if (!audit_enabled && msg_type != AUDIT_USER_AVC)
		return 0;
		/* exit early if there isn't at least one character to print */
		if (data_len < 2)
		return -EINVAL;

		err = audit_filter(msg_type, AUDIT_FILTER_USER);
		if (err == 1) { /* match or error */

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