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authorJan200101 <sentrycraft123@gmail.com>2020-10-17 20:13:47 +0200
committerJan200101 <sentrycraft123@gmail.com>2020-12-05 19:40:07 +0100
commit8f25b8829153510c5c47d4f902a66cb5e78cfbcf (patch)
tree524e9e48c4229d08a8f8e4a3c12077c2077f0e5b /SOURCES/CVE-2020-16119-DCCP-CCID-structure-use-after-free.patch
parenta8d3270837f54821b82d186d96587b7f2e207c95 (diff)
downloadkernel-fsync-8f25b8829153510c5c47d4f902a66cb5e78cfbcf.tar.gz
kernel-fsync-8f25b8829153510c5c47d4f902a66cb5e78cfbcf.zip
kernel 5.8.15
Diffstat (limited to 'SOURCES/CVE-2020-16119-DCCP-CCID-structure-use-after-free.patch')
-rw-r--r--SOURCES/CVE-2020-16119-DCCP-CCID-structure-use-after-free.patch305
1 files changed, 305 insertions, 0 deletions
diff --git a/SOURCES/CVE-2020-16119-DCCP-CCID-structure-use-after-free.patch b/SOURCES/CVE-2020-16119-DCCP-CCID-structure-use-after-free.patch
new file mode 100644
index 0000000..7eb981e
--- /dev/null
+++ b/SOURCES/CVE-2020-16119-DCCP-CCID-structure-use-after-free.patch
@@ -0,0 +1,305 @@
+From MAILER-DAEMON Wed Oct 14 16:34:37 2020
+From: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
+To: netdev@vger.kernel.org
+Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk>, "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, Thadeu Lima de Souza Cascardo <cascardo@canonical.com>, "Gustavo A. R. Silva" <gustavoars@kernel.org>, "Alexander A. Klimov" <grandmaster@al2klimov.de>, Kees Cook <keescook@chromium.org>, Eric Dumazet <edumazet@google.com>, Alexey Kodanev <alexey.kodanev@oracle.com>, dccp@vger.kernel.org, linux-kernel@vger.kernel.org
+Subject: [PATCH 1/2] dccp: ccid: move timers to struct dccp_sock
+Date: Tue, 13 Oct 2020 19:18:48 +0200
+Message-Id: <20201013171849.236025-2-kleber.souza@canonical.com>
+In-Reply-To: <20201013171849.236025-1-kleber.souza@canonical.com>
+References: <20201013171849.236025-1-kleber.souza@canonical.com>
+List-ID: <linux-kernel.vger.kernel.org>
+X-Mailing-List: linux-kernel@vger.kernel.org
+MIME-Version: 1.0
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 7bit
+
+From: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
+
+When dccps_hc_tx_ccid is freed, ccid timers may still trigger. The reason
+del_timer_sync can't be used is because this relies on keeping a reference
+to struct sock. But as we keep a pointer to dccps_hc_tx_ccid and free that
+during disconnect, the timer should really belong to struct dccp_sock.
+
+This addresses CVE-2020-16119.
+
+Fixes: 839a6094140a (net: dccp: Convert timers to use timer_setup())
+Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
+Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
+Acked-bd: Richard Sailer <richard_siegfried@systemli.org>
+---
+ include/linux/dccp.h | 2 ++
+ net/dccp/ccids/ccid2.c | 32 +++++++++++++++++++-------------
+ net/dccp/ccids/ccid3.c | 30 ++++++++++++++++++++----------
+ 3 files changed, 41 insertions(+), 23 deletions(-)
+
+diff --git a/include/linux/dccp.h b/include/linux/dccp.h
+index 07e547c02fd8..504afa1a4be6 100644
+--- a/include/linux/dccp.h
++++ b/include/linux/dccp.h
+@@ -259,6 +259,7 @@ struct dccp_ackvec;
+ * @dccps_sync_scheduled - flag which signals "send out-of-band message soon"
+ * @dccps_xmitlet - tasklet scheduled by the TX CCID to dequeue data packets
+ * @dccps_xmit_timer - used by the TX CCID to delay sending (rate-based pacing)
++ * @dccps_ccid_timer - used by the CCIDs
+ * @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs)
+ */
+ struct dccp_sock {
+@@ -303,6 +304,7 @@ struct dccp_sock {
+ __u8 dccps_sync_scheduled:1;
+ struct tasklet_struct dccps_xmitlet;
+ struct timer_list dccps_xmit_timer;
++ struct timer_list dccps_ccid_timer;
+ };
+
+ static inline struct dccp_sock *dccp_sk(const struct sock *sk)
+diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
+index 3da1f77bd039..dbca1f1e2449 100644
+--- a/net/dccp/ccids/ccid2.c
++++ b/net/dccp/ccids/ccid2.c
+@@ -126,21 +126,26 @@ static void dccp_tasklet_schedule(struct sock *sk)
+
+ static void ccid2_hc_tx_rto_expire(struct timer_list *t)
+ {
+- struct ccid2_hc_tx_sock *hc = from_timer(hc, t, tx_rtotimer);
+- struct sock *sk = hc->sk;
+- const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
++ struct dccp_sock *dp = from_timer(dp, t, dccps_ccid_timer);
++ struct sock *sk = (struct sock *)dp;
++ struct ccid2_hc_tx_sock *hc;
++ bool sender_was_blocked;
+
+ bh_lock_sock(sk);
++
++ if (inet_sk_state_load(sk) == DCCP_CLOSED)
++ goto out;
++
++ hc = ccid_priv(dp->dccps_hc_tx_ccid);
++ sender_was_blocked = ccid2_cwnd_network_limited(hc);
++
+ if (sock_owned_by_user(sk)) {
+- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + HZ / 5);
++ sk_reset_timer(sk, &dp->dccps_ccid_timer, jiffies + HZ / 5);
+ goto out;
+ }
+
+ ccid2_pr_debug("RTO_EXPIRE\n");
+
+- if (sk->sk_state == DCCP_CLOSED)
+- goto out;
+-
+ /* back-off timer */
+ hc->tx_rto <<= 1;
+ if (hc->tx_rto > DCCP_RTO_MAX)
+@@ -166,7 +171,7 @@ static void ccid2_hc_tx_rto_expire(struct timer_list *t)
+ if (sender_was_blocked)
+ dccp_tasklet_schedule(sk);
+ /* restart backed-off timer */
+- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
++ sk_reset_timer(sk, &dp->dccps_ccid_timer, jiffies + hc->tx_rto);
+ out:
+ bh_unlock_sock(sk);
+ sock_put(sk);
+@@ -330,7 +335,7 @@ static void ccid2_hc_tx_packet_sent(struct sock *sk, unsigned int len)
+ }
+ #endif
+
+- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
++ sk_reset_timer(sk, &dp->dccps_ccid_timer, jiffies + hc->tx_rto);
+
+ #ifdef CONFIG_IP_DCCP_CCID2_DEBUG
+ do {
+@@ -700,9 +705,9 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
+
+ /* restart RTO timer if not all outstanding data has been acked */
+ if (hc->tx_pipe == 0)
+- sk_stop_timer(sk, &hc->tx_rtotimer);
++ sk_stop_timer(sk, &dp->dccps_ccid_timer);
+ else
+- sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
++ sk_reset_timer(sk, &dp->dccps_ccid_timer, jiffies + hc->tx_rto);
+ done:
+ /* check if incoming Acks allow pending packets to be sent */
+ if (sender_was_blocked && !ccid2_cwnd_network_limited(hc))
+@@ -737,17 +742,18 @@ static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
+ hc->tx_last_cong = hc->tx_lsndtime = hc->tx_cwnd_stamp = ccid2_jiffies32;
+ hc->tx_cwnd_used = 0;
+ hc->sk = sk;
+- timer_setup(&hc->tx_rtotimer, ccid2_hc_tx_rto_expire, 0);
++ timer_setup(&dp->dccps_ccid_timer, ccid2_hc_tx_rto_expire, 0);
+ INIT_LIST_HEAD(&hc->tx_av_chunks);
+ return 0;
+ }
+
+ static void ccid2_hc_tx_exit(struct sock *sk)
+ {
++ struct dccp_sock *dp = dccp_sk(sk);
+ struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+ int i;
+
+- sk_stop_timer(sk, &hc->tx_rtotimer);
++ sk_stop_timer(sk, &dp->dccps_ccid_timer);
+
+ for (i = 0; i < hc->tx_seqbufc; i++)
+ kfree(hc->tx_seqbuf[i]);
+diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
+index b9ee1a4a8955..685f4d046c0d 100644
+--- a/net/dccp/ccids/ccid3.c
++++ b/net/dccp/ccids/ccid3.c
+@@ -184,17 +184,24 @@ static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc,
+
+ static void ccid3_hc_tx_no_feedback_timer(struct timer_list *t)
+ {
+- struct ccid3_hc_tx_sock *hc = from_timer(hc, t, tx_no_feedback_timer);
+- struct sock *sk = hc->sk;
++ struct dccp_sock *dp = from_timer(dp, t, dccps_ccid_timer);
++ struct ccid3_hc_tx_sock *hc;
++ struct sock *sk = (struct sock *)dp;
+ unsigned long t_nfb = USEC_PER_SEC / 5;
+
+ bh_lock_sock(sk);
++
++ if (inet_sk_state_load(sk) == DCCP_CLOSED)
++ goto out;
++
+ if (sock_owned_by_user(sk)) {
+ /* Try again later. */
+ /* XXX: set some sensible MIB */
+ goto restart_timer;
+ }
+
++ hc = ccid_priv(dp->dccps_hc_tx_ccid);
++
+ ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
+ ccid3_tx_state_name(hc->tx_state));
+
+@@ -250,8 +257,8 @@ static void ccid3_hc_tx_no_feedback_timer(struct timer_list *t)
+ t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
+
+ restart_timer:
+- sk_reset_timer(sk, &hc->tx_no_feedback_timer,
+- jiffies + usecs_to_jiffies(t_nfb));
++ sk_reset_timer(sk, &dp->dccps_ccid_timer,
++ jiffies + usecs_to_jiffies(t_nfb));
+ out:
+ bh_unlock_sock(sk);
+ sock_put(sk);
+@@ -280,7 +287,7 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
+ return -EBADMSG;
+
+ if (hc->tx_state == TFRC_SSTATE_NO_SENT) {
+- sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies +
++ sk_reset_timer(sk, &dp->dccps_ccid_timer, (jiffies +
+ usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
+ hc->tx_last_win_count = 0;
+ hc->tx_t_last_win_count = now;
+@@ -354,6 +361,7 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
+ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
+ {
+ struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
++ struct dccp_sock *dp = dccp_sk(sk);
+ struct tfrc_tx_hist_entry *acked;
+ ktime_t now;
+ unsigned long t_nfb;
+@@ -420,7 +428,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
+ (unsigned int)(hc->tx_x >> 6));
+
+ /* unschedule no feedback timer */
+- sk_stop_timer(sk, &hc->tx_no_feedback_timer);
++ sk_stop_timer(sk, &dp->dccps_ccid_timer);
+
+ /*
+ * As we have calculated new ipi, delta, t_nom it is possible
+@@ -445,8 +453,8 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
+ "expire in %lu jiffies (%luus)\n",
+ dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb);
+
+- sk_reset_timer(sk, &hc->tx_no_feedback_timer,
+- jiffies + usecs_to_jiffies(t_nfb));
++ sk_reset_timer(sk, &dp->dccps_ccid_timer,
++ jiffies + usecs_to_jiffies(t_nfb));
+ }
+
+ static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+@@ -488,21 +496,23 @@ static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
+
+ static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
+ {
++ struct dccp_sock *dp = dccp_sk(sk);
+ struct ccid3_hc_tx_sock *hc = ccid_priv(ccid);
+
+ hc->tx_state = TFRC_SSTATE_NO_SENT;
+ hc->tx_hist = NULL;
+ hc->sk = sk;
+- timer_setup(&hc->tx_no_feedback_timer,
++ timer_setup(&dp->dccps_ccid_timer,
+ ccid3_hc_tx_no_feedback_timer, 0);
+ return 0;
+ }
+
+ static void ccid3_hc_tx_exit(struct sock *sk)
+ {
++ struct dccp_sock *dp = dccp_sk(sk);
+ struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
+
+- sk_stop_timer(sk, &hc->tx_no_feedback_timer);
++ sk_stop_timer(sk, &dp->dccps_ccid_timer);
+ tfrc_tx_hist_purge(&hc->tx_hist);
+ }
+
+--
+2.25.1
+
+
+From MAILER-DAEMON Wed Oct 14 16:34:37 2020
+From: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
+To: netdev@vger.kernel.org
+Cc: Gerrit Renker <gerrit@erg.abdn.ac.uk>, "David S. Miller" <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>, Thadeu Lima de Souza Cascardo <cascardo@canonical.com>, "Gustavo A. R. Silva" <gustavoars@kernel.org>, "Alexander A. Klimov" <grandmaster@al2klimov.de>, Kees Cook <keescook@chromium.org>, Eric Dumazet <edumazet@google.com>, Alexey Kodanev <alexey.kodanev@oracle.com>, dccp@vger.kernel.org, linux-kernel@vger.kernel.org
+Subject: [PATCH 2/2] Revert "dccp: don't free ccid2_hc_tx_sock struct in dccp_disconnect()"
+Date: Tue, 13 Oct 2020 19:18:49 +0200
+Message-Id: <20201013171849.236025-3-kleber.souza@canonical.com>
+In-Reply-To: <20201013171849.236025-1-kleber.souza@canonical.com>
+References: <20201013171849.236025-1-kleber.souza@canonical.com>
+List-ID: <linux-kernel.vger.kernel.org>
+X-Mailing-List: linux-kernel@vger.kernel.org
+MIME-Version: 1.0
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 7bit
+
+From: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
+
+This reverts commit 2677d20677314101293e6da0094ede7b5526d2b1.
+
+This fixes an issue that after disconnect, dccps_hc_tx_ccid will still be
+kept, allowing the socket to be reused as a listener socket, and the cloned
+socket will free its dccps_hc_tx_ccid, leading to a later use after free,
+when the listener socket is closed.
+
+This addresses CVE-2020-16119.
+
+Fixes: 2677d2067731 (dccp: don't free ccid2_hc_tx_sock struct in dccp_disconnect())
+Reported-by: Hadar Manor
+Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
+Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
+Acked-by: Richard Sailer <richard_siegfried@systemli.org>
+---
+ net/dccp/proto.c | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/net/dccp/proto.c b/net/dccp/proto.c
+index 6d705d90c614..359e848dba6c 100644
+--- a/net/dccp/proto.c
++++ b/net/dccp/proto.c
+@@ -279,7 +279,9 @@ int dccp_disconnect(struct sock *sk, int flags)
+
+ dccp_clear_xmit_timers(sk);
+ ccid_hc_rx_delete(dp->dccps_hc_rx_ccid, sk);
++ ccid_hc_tx_delete(dp->dccps_hc_tx_ccid, sk);
+ dp->dccps_hc_rx_ccid = NULL;
++ dp->dccps_hc_tx_ccid = NULL;
+
+ __skb_queue_purge(&sk->sk_receive_queue);
+ __skb_queue_purge(&sk->sk_write_queue);
+--
+2.25.1
+
+