[src/trunk]: src/sys/net80211 Fix use-after-free: ieee80211_crypto_decap does...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/683886845351
branches:  trunk
changeset: 828368:683886845351
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Dec 10 08:56:23 2017 +0000

description:
Fix use-after-free: ieee80211_crypto_decap does a pullup on the mbuf but
the updated pointer is not passed back. Looks like it is triggerable
remotely.

diffstat:

 sys/net80211/ieee80211_crypto.c |  8 +++++---
 sys/net80211/ieee80211_crypto.h |  4 ++--
 sys/net80211/ieee80211_input.c  |  8 ++++----
 3 files changed, 11 insertions(+), 9 deletions(-)

diffs (97 lines):

diff -r 51f588a7e565 -r 683886845351 sys/net80211/ieee80211_crypto.c
--- a/sys/net80211/ieee80211_crypto.c   Sun Dec 10 08:48:15 2017 +0000
+++ b/sys/net80211/ieee80211_crypto.c   Sun Dec 10 08:56:23 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ieee80211_crypto.c,v 1.17 2015/08/24 22:21:26 pooka Exp $      */
+/*     $NetBSD: ieee80211_crypto.c,v 1.18 2017/12/10 08:56:23 maxv Exp $       */
 /*-
  * Copyright (c) 2001 Atsushi Onoe
  * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
@@ -36,7 +36,7 @@
 __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto.c,v 1.12 2005/08/08 18:46:35 sam Exp $");
 #endif
 #ifdef __NetBSD__
-__KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto.c,v 1.17 2015/08/24 22:21:26 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto.c,v 1.18 2017/12/10 08:56:23 maxv Exp $");
 #endif
 
 #ifdef _KERNEL_OPT
@@ -565,7 +565,7 @@
  */
 struct ieee80211_key *
 ieee80211_crypto_decap(struct ieee80211com *ic,
-       struct ieee80211_node *ni, struct mbuf *m, int hdrlen)
+       struct ieee80211_node *ni, struct mbuf **mp, int hdrlen)
 {
 #define        IEEE80211_WEP_HDRLEN    (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
 #define        IEEE80211_WEP_MINLEN \
@@ -574,6 +574,7 @@
        struct ieee80211_key *k;
        struct ieee80211_frame *wh;
        const struct ieee80211_cipher *cip;
+       struct mbuf *m = *mp;
        u_int8_t keyid;
 
        /* NB: this minimum size data frame could be bigger */
@@ -605,6 +606,7 @@
        cip = k->wk_cipher;
        if (m->m_len < hdrlen + cip->ic_header &&
            (m = m_pullup(m, hdrlen + cip->ic_header)) == NULL) {
+               *mp = NULL;
                IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
                    "[%s] unable to pullup %s header\n",
                    ether_sprintf(wh->i_addr2), cip->ic_name);
diff -r 51f588a7e565 -r 683886845351 sys/net80211/ieee80211_crypto.h
--- a/sys/net80211/ieee80211_crypto.h   Sun Dec 10 08:48:15 2017 +0000
+++ b/sys/net80211/ieee80211_crypto.h   Sun Dec 10 08:56:23 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ieee80211_crypto.h,v 1.11 2009/01/03 03:43:23 yamt Exp $       */
+/*     $NetBSD: ieee80211_crypto.h,v 1.12 2017/12/10 08:56:23 maxv Exp $       */
 /*-
  * Copyright (c) 2001 Atsushi Onoe
  * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
@@ -181,7 +181,7 @@
 struct ieee80211_key *ieee80211_crypto_encap(struct ieee80211com *,
                struct ieee80211_node *, struct mbuf *);
 struct ieee80211_key *ieee80211_crypto_decap(struct ieee80211com *,
-               struct ieee80211_node *, struct mbuf *, int);
+               struct ieee80211_node *, struct mbuf **, int);
 
 /*
  * Check and remove any MIC.
diff -r 51f588a7e565 -r 683886845351 sys/net80211/ieee80211_input.c
--- a/sys/net80211/ieee80211_input.c    Sun Dec 10 08:48:15 2017 +0000
+++ b/sys/net80211/ieee80211_input.c    Sun Dec 10 08:56:23 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ieee80211_input.c,v 1.90 2017/12/10 08:48:15 maxv Exp $        */
+/*     $NetBSD: ieee80211_input.c,v 1.91 2017/12/10 08:56:23 maxv Exp $        */
 /*-
  * Copyright (c) 2001 Atsushi Onoe
  * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
@@ -36,7 +36,7 @@
 __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_input.c,v 1.81 2005/08/10 16:22:29 sam Exp $");
 #endif
 #ifdef __NetBSD__
-__KERNEL_RCSID(0, "$NetBSD: ieee80211_input.c,v 1.90 2017/12/10 08:48:15 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ieee80211_input.c,v 1.91 2017/12/10 08:56:23 maxv Exp $");
 #endif
 
 #ifdef _KERNEL_OPT
@@ -454,7 +454,7 @@
                                IEEE80211_NODE_STAT(ni, rx_noprivacy);
                                goto out;
                        }
-                       key = ieee80211_crypto_decap(ic, ni, m, hdrspace);
+                       key = ieee80211_crypto_decap(ic, ni, &m, hdrspace);
                        if (key == NULL) {
                                /* NB: stats+msgs handled in crypto_decap */
                                IEEE80211_NODE_STAT(ni, rx_wepfail);
@@ -595,7 +595,7 @@
                                goto out;
                        }
                        hdrspace = ieee80211_hdrspace(ic, wh);
-                       key = ieee80211_crypto_decap(ic, ni, m, hdrspace);
+                       key = ieee80211_crypto_decap(ic, ni, &m, hdrspace);
                        if (key == NULL) {
                                /* NB: stats+msgs handled in crypto_decap */
                                goto out;