From: Eric Dumazet edumazet@google.com
[ Upstream commit 457fed775c97ac2c0cd1672aaf2ff2c8a6235e87 ]
As nlmsg_put() does not clear the memory that is reserved, it this the caller responsability to make sure all of this memory will be written, in order to not reveal prior content.
While we are at it, we can provide the socket cookie even if clsock is not set.
syzbot reported :
BUG: KMSAN: uninit-value in __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline] BUG: KMSAN: uninit-value in __fswab32 include/uapi/linux/swab.h:59 [inline] BUG: KMSAN: uninit-value in __swab32p include/uapi/linux/swab.h:179 [inline] BUG: KMSAN: uninit-value in __be32_to_cpup include/uapi/linux/byteorder/little_endian.h:82 [inline] BUG: KMSAN: uninit-value in get_unaligned_be32 include/linux/unaligned/access_ok.h:30 [inline] BUG: KMSAN: uninit-value in ____bpf_skb_load_helper_32 net/core/filter.c:240 [inline] BUG: KMSAN: uninit-value in ____bpf_skb_load_helper_32_no_cache net/core/filter.c:255 [inline] BUG: KMSAN: uninit-value in bpf_skb_load_helper_32_no_cache+0x14a/0x390 net/core/filter.c:252 CPU: 1 PID: 5262 Comm: syz-executor.5 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline] __fswab32 include/uapi/linux/swab.h:59 [inline] __swab32p include/uapi/linux/swab.h:179 [inline] __be32_to_cpup include/uapi/linux/byteorder/little_endian.h:82 [inline] get_unaligned_be32 include/linux/unaligned/access_ok.h:30 [inline] ____bpf_skb_load_helper_32 net/core/filter.c:240 [inline] ____bpf_skb_load_helper_32_no_cache net/core/filter.c:255 [inline] bpf_skb_load_helper_32_no_cache+0x14a/0x390 net/core/filter.c:252
Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127 kmsan_kmalloc_large+0x73/0xc0 mm/kmsan/kmsan_hooks.c:128 kmalloc_large_node_hook mm/slub.c:1406 [inline] kmalloc_large_node+0x282/0x2c0 mm/slub.c:3841 __kmalloc_node_track_caller+0x44b/0x1200 mm/slub.c:4368 __kmalloc_reserve net/core/skbuff.c:141 [inline] __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:209 alloc_skb include/linux/skbuff.h:1049 [inline] netlink_dump+0x44b/0x1ab0 net/netlink/af_netlink.c:2224 __netlink_dump_start+0xbb2/0xcf0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:233 [inline] smc_diag_handler_dump+0x2ba/0x300 net/smc/smc_diag.c:242 sock_diag_rcv_msg+0x211/0x610 net/core/sock_diag.c:256 netlink_rcv_skb+0x451/0x650 net/netlink/af_netlink.c:2477 sock_diag_rcv+0x63/0x80 net/core/sock_diag.c:275 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0xf9e/0x1100 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x1248/0x14d0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg net/socket.c:659 [inline] kernel_sendmsg+0x433/0x440 net/socket.c:679 sock_no_sendpage+0x235/0x300 net/core/sock.c:2740 kernel_sendpage net/socket.c:3776 [inline] sock_sendpage+0x1e1/0x2c0 net/socket.c:937 pipe_to_sendpage+0x38c/0x4c0 fs/splice.c:458 splice_from_pipe_feed fs/splice.c:512 [inline] __splice_from_pipe+0x539/0xed0 fs/splice.c:636 splice_from_pipe fs/splice.c:671 [inline] generic_splice_sendpage+0x1d5/0x2d0 fs/splice.c:844 do_splice_from fs/splice.c:863 [inline] do_splice fs/splice.c:1170 [inline] __do_sys_splice fs/splice.c:1447 [inline] __se_sys_splice+0x2380/0x3350 fs/splice.c:1427 __x64_sys_splice+0x6e/0x90 fs/splice.c:1427 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: f16a7dd5cf27 ("smc: netlink interface for SMC sockets") Signed-off-by: Eric Dumazet edumazet@google.com Cc: Ursula Braun ubraun@linux.vnet.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/smc/smc_diag.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/net/smc/smc_diag.c +++ b/net/smc/smc_diag.c @@ -38,16 +38,15 @@ static void smc_diag_msg_common_fill(str { struct smc_sock *smc = smc_sk(sk);
+ memset(r, 0, sizeof(*r)); r->diag_family = sk->sk_family; + sock_diag_save_cookie(sk, r->id.idiag_cookie); if (!smc->clcsock) return; r->id.idiag_sport = htons(smc->clcsock->sk->sk_num); r->id.idiag_dport = smc->clcsock->sk->sk_dport; r->id.idiag_if = smc->clcsock->sk->sk_bound_dev_if; - sock_diag_save_cookie(sk, r->id.idiag_cookie); if (sk->sk_protocol == SMCPROTO_SMC) { - memset(&r->id.idiag_src, 0, sizeof(r->id.idiag_src)); - memset(&r->id.idiag_dst, 0, sizeof(r->id.idiag_dst)); r->id.idiag_src[0] = smc->clcsock->sk->sk_rcv_saddr; r->id.idiag_dst[0] = smc->clcsock->sk->sk_daddr; #if IS_ENABLED(CONFIG_IPV6)