[PATCH 4.20 089/111] tipc: fix uninit-value in tipc_nl_compat_bearer_enable

4.20-stable review patch. If anyone has any objections, please let me know.

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From: Ying Xue ying.xue@windriver.com

commit 0762216c0ad2a2fccd63890648eca491f2c83d9a upstream.

syzbot reported:

BUG: KMSAN: uninit-value in strlen+0x3b/0xa0 lib/string.c:484 CPU: 1 PID: 6371 Comm: syz-executor652 Not tainted 4.19.0-rc8+ #70 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+0x306/0x460 lib/dump_stack.c:113 kmsan_report+0x1a2/0x2e0 mm/kmsan/kmsan.c:917 __msan_warning+0x7c/0xe0 mm/kmsan/kmsan_instr.c:500 strlen+0x3b/0xa0 lib/string.c:484 nla_put_string include/net/netlink.h:1011 [inline] tipc_nl_compat_bearer_enable+0x238/0x7b0 net/tipc/netlink_compat.c:389 __tipc_nl_compat_doit net/tipc/netlink_compat.c:311 [inline] tipc_nl_compat_doit+0x39f/0xae0 net/tipc/netlink_compat.c:344 tipc_nl_compat_recv+0x147c/0x2760 net/tipc/netlink_compat.c:1107 genl_family_rcv_msg net/netlink/genetlink.c:601 [inline] genl_rcv_msg+0x185c/0x1a20 net/netlink/genetlink.c:626 netlink_rcv_skb+0x394/0x640 net/netlink/af_netlink.c:2454 genl_rcv+0x63/0x80 net/netlink/genetlink.c:637 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x166d/0x1720 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x1391/0x1420 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xe47/0x1200 net/socket.c:2116 __sys_sendmsg net/socket.c:2154 [inline] __do_sys_sendmsg net/socket.c:2163 [inline] __se_sys_sendmsg+0x307/0x460 net/socket.c:2161 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x440179 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fffef7beee8 EFLAGS: 00000213 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440179 RDX: 0000000000000000 RSI: 0000000020000100 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000213 R12: 0000000000401a00 R13: 0000000000401a90 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:255 [inline] kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:180 kmsan_kmalloc+0xa4/0x120 mm/kmsan/kmsan_hooks.c:104 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:113 slab_post_alloc_hook mm/slab.h:446 [inline] slab_alloc_node mm/slub.c:2727 [inline] __kmalloc_node_track_caller+0xb43/0x1400 mm/slub.c:4360 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x422/0xe90 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:996 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1189 [inline] netlink_sendmsg+0xcaf/0x1420 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg net/socket.c:631 [inline] ___sys_sendmsg+0xe47/0x1200 net/socket.c:2116 __sys_sendmsg net/socket.c:2154 [inline] __do_sys_sendmsg net/socket.c:2163 [inline] __se_sys_sendmsg+0x307/0x460 net/socket.c:2161 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291 entry_SYSCALL_64_after_hwframe+0x63/0xe7

The root cause is that we don't validate whether bear name is a valid string in tipc_nl_compat_bearer_enable().

Meanwhile, we also fix the same issue in the following functions: tipc_nl_compat_bearer_disable() tipc_nl_compat_link_stat_dump() tipc_nl_compat_media_set() tipc_nl_compat_bearer_set()

Reported-by: syzbot+b33d5cae0efd35dbfe77@syzkaller.appspotmail.com Signed-off-by: Ying Xue ying.xue@windriver.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/tipc/netlink_compat.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)

--- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -389,6 +389,7 @@ static int tipc_nl_compat_bearer_enable( struct nlattr *prop; struct nlattr *bearer; struct tipc_bearer_config *b; + int len;

b = (struct tipc_bearer_config *)TLV_DATA(msg->req);

@@ -396,6 +397,10 @@ static int tipc_nl_compat_bearer_enable( if (!bearer) return -EMSGSIZE;

+ len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_BEARER_NAME); + if (!string_is_valid(b->name, len)) + return -EINVAL; + if (nla_put_string(skb, TIPC_NLA_BEARER_NAME, b->name)) return -EMSGSIZE;

@@ -421,6 +426,7 @@ static int tipc_nl_compat_bearer_disable { char *name; struct nlattr *bearer; + int len;

name = (char *)TLV_DATA(msg->req);

@@ -428,6 +434,10 @@ static int tipc_nl_compat_bearer_disable if (!bearer) return -EMSGSIZE;

+ len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_BEARER_NAME); + if (!string_is_valid(name, len)) + return -EINVAL; + if (nla_put_string(skb, TIPC_NLA_BEARER_NAME, name)) return -EMSGSIZE;

@@ -488,6 +498,7 @@ static int tipc_nl_compat_link_stat_dump struct nlattr *prop[TIPC_NLA_PROP_MAX + 1]; struct nlattr *stats[TIPC_NLA_STATS_MAX + 1]; int err; + int len;

if (!attrs[TIPC_NLA_LINK]) return -EINVAL; @@ -514,6 +525,11 @@ static int tipc_nl_compat_link_stat_dump return err;

name = (char *)TLV_DATA(msg->req); + + len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_LINK_NAME); + if (!string_is_valid(name, len)) + return -EINVAL; + if (strcmp(name, nla_data(link[TIPC_NLA_LINK_NAME])) != 0) return 0;

@@ -654,6 +670,7 @@ static int tipc_nl_compat_media_set(stru struct nlattr *prop; struct nlattr *media; struct tipc_link_config *lc; + int len;

lc = (struct tipc_link_config *)TLV_DATA(msg->req);

@@ -661,6 +678,10 @@ static int tipc_nl_compat_media_set(stru if (!media) return -EMSGSIZE;

+ len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_MEDIA_NAME); + if (!string_is_valid(lc->name, len)) + return -EINVAL; + if (nla_put_string(skb, TIPC_NLA_MEDIA_NAME, lc->name)) return -EMSGSIZE;

@@ -681,6 +702,7 @@ static int tipc_nl_compat_bearer_set(str struct nlattr *prop; struct nlattr *bearer; struct tipc_link_config *lc; + int len;

lc = (struct tipc_link_config *)TLV_DATA(msg->req);

@@ -688,6 +710,10 @@ static int tipc_nl_compat_bearer_set(str if (!bearer) return -EMSGSIZE;

+ len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_MEDIA_NAME); + if (!string_is_valid(lc->name, len)) + return -EINVAL; + if (nla_put_string(skb, TIPC_NLA_BEARER_NAME, lc->name)) return -EMSGSIZE;