Commit f7dc4c9a authored Nov 08, 2017 by John Johansen Committed by Linus Torvalds Nov 08, 2017

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: cd1dbf76 ("apparmor: add the ability to mediate signals")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent fbc3edf7

security/apparmor/ipc.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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",