diff mbox series

[1/1] sctp: walk the list of asoc safely

Message ID 1550831307-3376-2-git-send-email-tyhicks@canonical.com
State New
Headers show
Series CVE-2019-8956 - SCTP use-after-free | expand

Commit Message

Tyler Hicks Feb. 22, 2019, 10:28 a.m. UTC 
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In sctp_sendmesg(), when walking the list of endpoint associations, the
association can be dropped from the list, making the list corrupt.
Properly handle this by using list_for_each_entry_safe()

Fixes: 4910280503f3 ("sctp: add support for snd flag SCTP_SENDALL process in sendmsg")
Reported-by: Secunia Research <vuln@secunia.com>
Tested-by: Secunia Research <vuln@secunia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

CVE-2019-8956

(cherry picked from commit ba59fb0273076637f0add4311faa990a5eec27c0)
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
---
 net/sctp/socket.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 9d903b870790..20ba3651cbc5 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -2039,7 +2039,7 @@  static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 	struct sctp_endpoint *ep = sctp_sk(sk)->ep;
 	struct sctp_transport *transport = NULL;
 	struct sctp_sndrcvinfo _sinfo, *sinfo;
-	struct sctp_association *asoc;
+	struct sctp_association *asoc, *tmp;
 	struct sctp_cmsgs cmsgs;
 	union sctp_addr *daddr;
 	bool new = false;
@@ -2065,7 +2065,7 @@  static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len)
 
 	/* SCTP_SENDALL process */
 	if ((sflags & SCTP_SENDALL) && sctp_style(sk, UDP)) {
-		list_for_each_entry(asoc, &ep->asocs, asocs) {
+		list_for_each_entry_safe(asoc, tmp, &ep->asocs, asocs) {
 			err = sctp_sendmsg_check_sflags(asoc, sflags, msg,
 							msg_len);
 			if (err == 0)