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authorJohn Fastabend <john.fastabend@gmail.com>2018-10-18 13:58:35 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2018-10-20 00:40:45 +0200
commit5032d079909d1ac5c2535acc32d5f01cd245d8ea (patch)
treeb88f31d2ef57332a57aede02d520c2b4c01baf9a /net/core/sock_map.c
parent540fefc08f75aedb517acbf525d393b8efddabd9 (diff)
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/core/sock_map.c')
-rw-r--r--net/core/sock_map.c11
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);