4.16-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit eb80ca476ec11f67a62691a93604b405ffc7d80c ]
syzbot/KMSAN reported an uninit-value in put_cmsg(), originating from rds_cmsg_recv().
Simply clear the structure, since we have holes there, or since rx_traces might be smaller than RDS_MSG_RX_DGRAM_TRACE_MAX.
BUG: KMSAN: uninit-value in copy_to_user include/linux/uaccess.h:184 [inline] BUG: KMSAN: uninit-value in put_cmsg+0x600/0x870 net/core/scm.c:242 CPU: 0 PID: 4459 Comm: syz-executor582 Not tainted 4.16.0+ #87 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 kmsan_internal_check_memory+0x135/0x1e0 mm/kmsan/kmsan.c:1157 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199 copy_to_user include/linux/uaccess.h:184 [inline] put_cmsg+0x600/0x870 net/core/scm.c:242 rds_cmsg_recv net/rds/recv.c:570 [inline] rds_recvmsg+0x2db5/0x3170 net/rds/recv.c:657 sock_recvmsg_nosec net/socket.c:803 [inline] sock_recvmsg+0x1d0/0x230 net/socket.c:810 ___sys_recvmsg+0x3fb/0x810 net/socket.c:2205 __sys_recvmsg net/socket.c:2250 [inline] SYSC_recvmsg+0x298/0x3c0 net/socket.c:2262 SyS_recvmsg+0x54/0x80 net/socket.c:2257 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Fixes: 3289025aedc0 ("RDS: add receive message trace used by application") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: Santosh Shilimkar santosh.shilimkar@oracle.com Cc: linux-rdma linux-rdma@vger.kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/rds/recv.c | 1 + 1 file changed, 1 insertion(+)
--- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -558,6 +558,7 @@ static int rds_cmsg_recv(struct rds_inco struct rds_cmsg_rx_trace t; int i, j;
+ memset(&t, 0, sizeof(t)); inc->i_rx_lat_trace[RDS_MSG_RX_CMSG] = local_clock(); t.rx_traces = rs->rs_rx_traces; for (i = 0; i < rs->rs_rx_traces; i++) {