From: John Johansen Date: Wed, 8 Nov 2017 16:09:52 +0000 (-0800) Subject: apparmor: fix off-by-one comparison on MAXMAPPED_SIG X-Git-Tag: v4.14~19 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=f7dc4c9a855a13dbb33294c9fc94f17af03f6291;p=mirror_ubuntu-bionic-kernel.git apparmor: fix off-by-one comparison on MAXMAPPED_SIG This came in yesterday, and I have verified our regression tests were missing this and it can cause an oops. Please apply. There is a an off-by-one comparision on sig against MAXMAPPED_SIG that can lead to a read outside the sig_map array if sig is MAXMAPPED_SIG. Fix this. Verified that the check is an out of bounds case that can cause an oops. Revised: add comparison fix to second case Fixes: cd1dbf76b23d ("apparmor: add the ability to mediate signals") Signed-off-by: Colin Ian King Signed-off-by: John Johansen Signed-off-by: Linus Torvalds --- diff --git a/security/apparmor/ipc.c b/security/apparmor/ipc.c index 66fb9ede9447..7ca0032e7ba9 100644 --- a/security/apparmor/ipc.c +++ b/security/apparmor/ipc.c @@ -128,7 +128,7 @@ static inline int map_signal_num(int sig) return SIGUNKNOWN; else if (sig >= SIGRTMIN) return sig - SIGRTMIN + 128; /* rt sigs mapped to 128 */ - else if (sig <= MAXMAPPED_SIG) + else if (sig < MAXMAPPED_SIG) return sig_map[sig]; return SIGUNKNOWN; } @@ -163,7 +163,7 @@ static void audit_signal_cb(struct audit_buffer *ab, void *va) audit_signal_mask(ab, aad(sa)->denied); } } - if (aad(sa)->signal <= MAXMAPPED_SIG) + if (aad(sa)->signal < MAXMAPPED_SIG) audit_log_format(ab, " signal=%s", sig_names[aad(sa)->signal]); else audit_log_format(ab, " signal=rtmin+%d",