diff options
| author | Eric Biggers <ebiggers@google.com> | 2019-10-06 14:24:25 -0700 |
|---|---|---|
| committer | Jakub Kicinski <jakub.kicinski@netronome.com> | 2019-10-08 13:23:05 -0700 |
| commit | b74555de21acd791f12c4a1aeaf653dd7ac21133 (patch) | |
| tree | 861c5ed79b737209cbec21fb47e3b2a49e738576 /net/llc/llc_c_ac.c | |
| parent | c6ee11c39fcc1fb55130748990a8f199e76263b4 (diff) | |
llc: fix sk_buff leak in llc_conn_service()
syzbot reported:
BUG: memory leak
unreferenced object 0xffff88811eb3de00 (size 224):
comm "syz-executor559", pid 7315, jiffies 4294943019 (age 10.300s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 a0 38 24 81 88 ff ff 00 c0 f2 15 81 88 ff ff ..8$............
backtrace:
[<000000008d1c66a1>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
[<000000008d1c66a1>] slab_post_alloc_hook mm/slab.h:439 [inline]
[<000000008d1c66a1>] slab_alloc_node mm/slab.c:3269 [inline]
[<000000008d1c66a1>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
[<00000000447d9496>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
[<000000000cdbf82f>] alloc_skb include/linux/skbuff.h:1058 [inline]
[<000000000cdbf82f>] llc_alloc_frame+0x66/0x110 net/llc/llc_sap.c:54
[<000000002418b52e>] llc_conn_ac_send_sabme_cmd_p_set_x+0x2f/0x140 net/llc/llc_c_ac.c:777
[<000000001372ae17>] llc_exec_conn_trans_actions net/llc/llc_conn.c:475 [inline]
[<000000001372ae17>] llc_conn_service net/llc/llc_conn.c:400 [inline]
[<000000001372ae17>] llc_conn_state_process+0x1ac/0x640 net/llc/llc_conn.c:75
[<00000000f27e53c1>] llc_establish_connection+0x110/0x170 net/llc/llc_if.c:109
[<00000000291b2ca0>] llc_ui_connect+0x10e/0x370 net/llc/af_llc.c:477
[<000000000f9c740b>] __sys_connect+0x11d/0x170 net/socket.c:1840
[...]
The bug is that most callers of llc_conn_send_pdu() assume it consumes a
reference to the skb, when actually due to commit b85ab56c3f81 ("llc:
properly handle dev_queue_xmit() return value") it doesn't.
Revert most of that commit, and instead make the few places that need
llc_conn_send_pdu() to *not* consume a reference call skb_get() before.
Fixes: b85ab56c3f81 ("llc: properly handle dev_queue_xmit() return value")
Reported-by: syzbot+6b825a6494a04cc0e3f7@syzkaller.appspotmail.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Diffstat (limited to 'net/llc/llc_c_ac.c')
| -rw-r--r-- | net/llc/llc_c_ac.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/llc/llc_c_ac.c b/net/llc/llc_c_ac.c index 4d78375f9872..647c0554d04c 100644 --- a/net/llc/llc_c_ac.c +++ b/net/llc/llc_c_ac.c @@ -372,6 +372,7 @@ int llc_conn_ac_send_i_cmd_p_set_1(struct sock *sk, struct sk_buff *skb) llc_pdu_init_as_i_cmd(skb, 1, llc->vS, llc->vR); rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac); if (likely(!rc)) { + skb_get(skb); llc_conn_send_pdu(sk, skb); llc_conn_ac_inc_vs_by_1(sk, skb); } @@ -389,7 +390,8 @@ static int llc_conn_ac_send_i_cmd_p_set_0(struct sock *sk, struct sk_buff *skb) llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR); rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac); if (likely(!rc)) { - rc = llc_conn_send_pdu(sk, skb); + skb_get(skb); + llc_conn_send_pdu(sk, skb); llc_conn_ac_inc_vs_by_1(sk, skb); } return rc; @@ -406,6 +408,7 @@ int llc_conn_ac_send_i_xxx_x_set_0(struct sock *sk, struct sk_buff *skb) llc_pdu_init_as_i_cmd(skb, 0, llc->vS, llc->vR); rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac); if (likely(!rc)) { + skb_get(skb); llc_conn_send_pdu(sk, skb); llc_conn_ac_inc_vs_by_1(sk, skb); } @@ -916,7 +919,8 @@ static int llc_conn_ac_send_i_rsp_f_set_ackpf(struct sock *sk, llc_pdu_init_as_i_cmd(skb, llc->ack_pf, llc->vS, llc->vR); rc = llc_mac_hdr_init(skb, llc->dev->dev_addr, llc->daddr.mac); if (likely(!rc)) { - rc = llc_conn_send_pdu(sk, skb); + skb_get(skb); + llc_conn_send_pdu(sk, skb); llc_conn_ac_inc_vs_by_1(sk, skb); } return rc; |