selinux: add the missing walk_size + len check in selinux_sctp_bind_connect

lxin · pcmoore · commit 292c997a1970 · 2019-03-11T16:00:44.000-04:00
As does in __sctp_connect(), when checking addrs in a while loop, after get the addr len according to sa_family, it's necessary to do the check walk_size + af->sockaddr_len > addrs_size to make sure it won't access an out-of-bounds addr. The same thing is needed in selinux_sctp_bind_connect(), otherwise an out-of-bounds issue can be triggered: [14548.772313] BUG: KASAN: slab-out-of-bounds in selinux_sctp_bind_connect+0x1aa/0x1f0 [14548.927083] Call Trace: [14548.938072] dump_stack+0x9a/0xe9 [14548.953015] print_address_description+0x65/0x22e [14548.996524] kasan_report.cold.6+0x92/0x1a6 [14549.015335] selinux_sctp_bind_connect+0x1aa/0x1f0 [14549.036947] security_sctp_bind_connect+0x58/0x90 [14549.058142] __sctp_setsockopt_connectx+0x5a/0x150 [sctp] [14549.081650] sctp_setsockopt.part.24+0x1322/0x3ce0 [sctp] Cc: stable@vger.kernel.org Fixes: d452930 ("selinux: Add SCTP support") Reported-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
@@ -5147,6 +5147,9 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname,
 			return -EINVAL;
 		}
 
+		if (walk_size + len > addrlen)
+			return -EINVAL;
+
 		err = -EINVAL;
 		switch (optname) {
 		/* Bind checks */

Original file line number	Diff line number	Diff line change
`@@ -5147,6 +5147,9 @@ static int selinux_sctp_bind_connect(struct sock *sk, int optname,`
`5147`	`5147`	`return -EINVAL;`
`5148`	`5148`	`}`
`5149`	`5149`
	`5150`	`+ if (walk_size + len > addrlen)`
	`5151`	`+ return -EINVAL;`
	`5152`	`+`
`5150`	`5153`	`err = -EINVAL;`
`5151`	`5154`	`switch (optname) {`
`5152`	`5155`	`/* Bind checks */`