diff --git a/debian/changelog b/debian/changelog index 28ef9f137..3f037080e 100644 --- a/debian/changelog +++ b/debian/changelog @@ -1,6 +1,8 @@ linux (4.2.5-2) 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 Sun, 08 Nov 2015 14:47:40 +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 000000000..a6c0f6a45 --- /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 +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 +Reviewed-by: Vegard Nossum +Reviewed-by: Sasha Levin +Cc: Vegard Nossum +Cc: Sasha Levin +Cc: Chien Yen +Cc: Santosh Shilimkar +Cc: David S. Miller +Cc: stable@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 +@@ -986,11 +986,13 @@ int rds_sendmsg(struct socket *sock, str + 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); + + /* size of rm including all sgs */ + ret = rds_rm_size(msg, payload_len); diff --git a/debian/patches/series b/debian/patches/series index 0f2520ec6..b55d509d1 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -105,3 +105,4 @@ bugfix/all/KEYS-Don-t-permit-request_key-to-construct-a-new-key.patch debian/target-fix-abi-change-in-4.2.4.patch debian/signal-fix-abi-change-in-4.2.4.patch bugfix/all/usbvision-fix-overflow-of-interfaces-array.patch +bugfix/all/rds-fix-race-condition-when-sending-a-message-on-unbound-socket.patch