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| author | John Fastabend <john.fastabend@gmail.com> | 2018-10-18 22:58:35 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-10-20 00:40:45 +0200 |
| commit | 5032d079909d1ac5c2535acc32d5f01cd245d8ea (patch) | |
| tree | b88f31d2ef57332a57aede02d520c2b4c01baf9a /net | |
| parent | bpf: remove unused variable (diff) | |
| download | linux-5032d079909d1ac5c2535acc32d5f01cd245d8ea.tar.xz linux-5032d079909d1ac5c2535acc32d5f01cd245d8ea.zip | |
bpf: skmsg, fix psock create on existing kcm/tls port
Before using the psock returned by sk_psock_get() when adding it to a
sockmap we need to ensure it is actually a sockmap based psock.
Previously we were only checking this after incrementing the reference
counter which was an error. This resulted in a slab-out-of-bounds
error when the psock was not actually a sockmap type.
This moves the check up so the reference counter is only used
if it is a sockmap psock.
Eric reported the following KASAN BUG,
BUG: KASAN: slab-out-of-bounds in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
BUG: KASAN: slab-out-of-bounds in refcount_inc_not_zero_checked+0x97/0x2f0 lib/refcount.c:120
Read of size 4 at addr ffff88019548be58 by task syz-executor4/22387
CPU: 1 PID: 22387 Comm: syz-executor4 Not tainted 4.19.0-rc7+ #264
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+0x1c4/0x2b4 lib/dump_stack.c:113
print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
check_memory_region_inline mm/kasan/kasan.c:260 [inline]
check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267
kasan_check_read+0x11/0x20 mm/kasan/kasan.c:272
atomic_read include/asm-generic/atomic-instrumented.h:21 [inline]
refcount_inc_not_zero_checked+0x97/0x2f0 lib/refcount.c:120
sk_psock_get include/linux/skmsg.h:379 [inline]
sock_map_link.isra.6+0x41f/0xe30 net/core/sock_map.c:178
sock_hash_update_common+0x19b/0x11e0 net/core/sock_map.c:669
sock_hash_update_elem+0x306/0x470 net/core/sock_map.c:738
map_update_elem+0x819/0xdf0 kernel/bpf/syscall.c:818
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/sock_map.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 3c0e44cb811a..be6092ac69f8 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -175,12 +175,13 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs, } } - psock = sk_psock_get(sk); + psock = sk_psock_get_checked(sk); + if (IS_ERR(psock)) { + ret = PTR_ERR(psock); + goto out_progs; + } + if (psock) { - if (!sk_has_psock(sk)) { - ret = -EBUSY; - goto out_progs; - } if ((msg_parser && READ_ONCE(psock->progs.msg_parser)) || (skb_progs && READ_ONCE(psock->progs.skb_parser))) { sk_psock_put(sk, psock); |