[linux] 02/02: RDS: fix race condition when sending a message on unbound socket (CVE-2015-7990).
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Sun Nov 8 14:24:40 UTC 2015
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benh pushed a commit to branch squeeze-security
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commit 0fe7c4ccc410fd8e33e95d87d9d64b2444f45ed8
Author: Ben Hutchings <ben at decadent.org.uk>
Date: Sun Nov 8 14:21:58 2015 +0000
RDS: fix race condition when sending a message on unbound socket (CVE-2015-7990).
---
debian/changelog | 2 +
...-when-sending-a-message-on-unbound-socket.patch | 69 ++++++++++++++++++++++
debian/patches/series/48squeeze17 | 1 +
3 files changed, 72 insertions(+)
diff --git a/debian/changelog b/debian/changelog
index dc74ee4..3b8caed 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,6 +1,8 @@
linux-2.6 (2.6.32-48squeeze17) UNRELEASED; urgency=medium
* usbvision: fix overflow of interfaces array (CVE-2015-7833)
+ * RDS: fix race condition when sending a message on unbound socket
+ (CVE-2015-7990)
-- Ben Hutchings <ben at decadent.org.uk> Sun, 08 Nov 2015 13:41:21 +0000
diff --git a/debian/patches/bugfix/all/rds-fix-race-condition-when-sending-a-message-on-unbound-socket.patch b/debian/patches/bugfix/all/rds-fix-race-condition-when-sending-a-message-on-unbound-socket.patch
new file mode 100644
index 0000000..ca6039e
--- /dev/null
+++ b/debian/patches/bugfix/all/rds-fix-race-condition-when-sending-a-message-on-unbound-socket.patch
@@ -0,0 +1,69 @@
+From: Quentin Casasnovas <quentin.casasnovas at oracle.com>
+Subject: RDS: fix race condition when sending a message on unbound socket.
+Date: Fri, 16 Oct 2015 17:11:42 +0200
+Origin: https://lkml.org/lkml/2015/10/16/530
+
+Sasha's found a NULL pointer dereference in the RDS connection code when
+sending a message to an apparently unbound socket. The problem is caused
+by the code checking if the socket is bound in rds_sendmsg(), which checks
+the rs_bound_addr field without taking a lock on the socket. This opens a
+race where rs_bound_addr is temporarily set but where the transport is not
+in rds_bind(), leading to a NULL pointer dereference when trying to
+dereference 'trans' in __rds_conn_create().
+
+Vegard wrote a reproducer for this issue, so kindly ask him to share if
+you're interested.
+
+I cannot reproduce the NULL pointer dereference using Vegard's reproducer
+with this patch, whereas I could without.
+
+Complete earlier incomplete fix to CVE-2015-6937:
+
+ 74e98eb08588 ("RDS: verify the underlying transport exists before creating a connection")
+
+Signed-off-by: Quentin Casasnovas <quentin.casasnovas at oracle.com>
+Reviewed-by: Vegard Nossum <vegard.nossum at oracle.com>
+Reviewed-by: Sasha Levin <sasha.levin at oracle.com>
+Cc: Vegard Nossum <vegard.nossum at oracle.com>
+Cc: Sasha Levin <sasha.levin at oracle.com>
+Cc: Chien Yen <chien.yen at oracle.com>
+Cc: Santosh Shilimkar <santosh.shilimkar at oracle.com>
+Cc: David S. Miller <davem at davemloft.net>
+Cc: stable at vger.kernel.org
+---
+ net/rds/connection.c | 6 ------
+ net/rds/send.c | 4 +++-
+ 2 files changed, 3 insertions(+), 7 deletions(-)
+
+--- a/net/rds/connection.c
++++ b/net/rds/connection.c
+@@ -187,12 +187,6 @@ new_conn:
+ }
+ }
+
+- if (trans == NULL) {
+- kmem_cache_free(rds_conn_slab, conn);
+- conn = ERR_PTR(-ENODEV);
+- goto out;
+- }
+-
+ conn->c_trans = trans;
+
+ ret = trans->conn_alloc(conn, gfp);
+--- a/net/rds/send.c
++++ b/net/rds/send.c
+@@ -842,11 +842,13 @@ int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
+ release_sock(sk);
+ }
+
+- /* racing with another thread binding seems ok here */
++ lock_sock(sk);
+ if (daddr == 0 || rs->rs_bound_addr == 0) {
++ release_sock(sk);
+ ret = -ENOTCONN; /* XXX not a great errno */
+ goto out;
+ }
++ release_sock(sk);
+
+ rm = rds_message_copy_from_user(msg->msg_iov, payload_len);
+ if (IS_ERR(rm)) {
diff --git a/debian/patches/series/48squeeze17 b/debian/patches/series/48squeeze17
index 537c133..8ea518f 100644
--- a/debian/patches/series/48squeeze17
+++ b/debian/patches/series/48squeeze17
@@ -1 +1,2 @@
+ bugfix/all/usbvision-fix-overflow-of-interfaces-array.patch
++ bugfix/all/rds-fix-race-condition-when-sending-a-message-on-unbound-socket.patch
--
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