diff options
| author | Eric Dumazet | 2023-09-08 18:13:59 +0000 |
|---|---|---|
| committer | Steffen Klassert | 2023-09-13 09:20:28 +0200 |
| commit | 3e4bc23926b83c3c67e5f61ae8571602754131a6 (patch) | |
| tree | 25c2d057a2688cc56aa975eab469bf79f45dcd84 /net/xfrm | |
| parent | f7c4e3e5d4f6609b4725a97451948ca2e425379a (diff) | |
xfrm: fix a data-race in xfrm_gen_index()
xfrm_gen_index() mutual exclusion uses net->xfrm.xfrm_policy_lock.
This means we must use a per-netns idx_generator variable,
instead of a static one.
Alternative would be to use an atomic variable.
syzbot reported:
BUG: KCSAN: data-race in xfrm_sk_policy_insert / xfrm_sk_policy_insert
write to 0xffffffff87005938 of 4 bytes by task 29466 on cpu 0:
xfrm_gen_index net/xfrm/xfrm_policy.c:1385 [inline]
xfrm_sk_policy_insert+0x262/0x640 net/xfrm/xfrm_policy.c:2347
xfrm_user_policy+0x413/0x540 net/xfrm/xfrm_state.c:2639
do_ipv6_setsockopt+0x1317/0x2ce0 net/ipv6/ipv6_sockglue.c:943
ipv6_setsockopt+0x57/0x130 net/ipv6/ipv6_sockglue.c:1012
rawv6_setsockopt+0x21e/0x410 net/ipv6/raw.c:1054
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697
__sys_setsockopt+0x1c9/0x230 net/socket.c:2263
__do_sys_setsockopt net/socket.c:2274 [inline]
__se_sys_setsockopt net/socket.c:2271 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2271
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
read to 0xffffffff87005938 of 4 bytes by task 29460 on cpu 1:
xfrm_sk_policy_insert+0x13e/0x640
xfrm_user_policy+0x413/0x540 net/xfrm/xfrm_state.c:2639
do_ipv6_setsockopt+0x1317/0x2ce0 net/ipv6/ipv6_sockglue.c:943
ipv6_setsockopt+0x57/0x130 net/ipv6/ipv6_sockglue.c:1012
rawv6_setsockopt+0x21e/0x410 net/ipv6/raw.c:1054
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697
__sys_setsockopt+0x1c9/0x230 net/socket.c:2263
__do_sys_setsockopt net/socket.c:2274 [inline]
__se_sys_setsockopt net/socket.c:2271 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2271
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x00006ad8 -> 0x00006b18
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 29460 Comm: syz-executor.1 Not tainted 6.5.0-rc5-syzkaller-00243-g9106536c1aa3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Fixes: 1121994c803f ("netns xfrm: policy insertion in netns")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Diffstat (limited to 'net/xfrm')
| -rw-r--r-- | net/xfrm/xfrm_policy.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 113fb7e9cdaf..99df2862bdc9 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -1375,8 +1375,6 @@ EXPORT_SYMBOL(xfrm_policy_hash_rebuild); * of an absolute inpredictability of ordering of rules. This will not pass. */ static u32 xfrm_gen_index(struct net *net, int dir, u32 index) { - static u32 idx_generator; - for (;;) { struct hlist_head *list; struct xfrm_policy *p; @@ -1384,8 +1382,8 @@ static u32 xfrm_gen_index(struct net *net, int dir, u32 index) int found; if (!index) { - idx = (idx_generator | dir); - idx_generator += 8; + idx = (net->xfrm.idx_generator | dir); + net->xfrm.idx_generator += 8; } else { idx = index; index = 0; |