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| author | Hoang Le <hoang.h.le@dektech.com.au> | 2021-01-08 14:13:37 +0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-01-09 14:44:47 -0800 |
| commit | b77413446408fdd256599daf00d5be72b5f3e7c6 (patch) | |
| tree | 59aff1a858a335503c3cfee12224bc267b4bdab4 /net/tipc/link.c | |
| parent | 3502bd9b5762154ff11665f3f18f6d7dcc6f781c (diff) | |
| download | linux-b77413446408fdd256599daf00d5be72b5f3e7c6.tar.gz linux-b77413446408fdd256599daf00d5be72b5f3e7c6.tar.bz2 linux-b77413446408fdd256599daf00d5be72b5f3e7c6.zip | |
tipc: fix NULL deref in tipc_link_xmit()
The buffer list can have zero skb as following path:
tipc_named_node_up()->tipc_node_xmit()->tipc_link_xmit(), so
we need to check the list before casting an &sk_buff.
Fault report:
[] tipc: Bulk publication failure
[] general protection fault, probably for non-canonical [#1] PREEMPT [...]
[] KASAN: null-ptr-deref in range [0x00000000000000c8-0x00000000000000cf]
[] CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Not tainted 5.10.0-rc4+ #2
[] Hardware name: Bochs ..., BIOS Bochs 01/01/2011
[] RIP: 0010:tipc_link_xmit+0xc1/0x2180
[] Code: 24 b8 00 00 00 00 4d 39 ec 4c 0f 44 e8 e8 d7 0a 10 f9 48 [...]
[] RSP: 0018:ffffc90000006ea0 EFLAGS: 00010202
[] RAX: dffffc0000000000 RBX: ffff8880224da000 RCX: 1ffff11003d3cc0d
[] RDX: 0000000000000019 RSI: ffffffff886007b9 RDI: 00000000000000c8
[] RBP: ffffc90000007018 R08: 0000000000000001 R09: fffff52000000ded
[] R10: 0000000000000003 R11: fffff52000000dec R12: ffffc90000007148
[] R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000007018
[] FS: 0000000000000000(0000) GS:ffff888037400000(0000) knlGS:000[...]
[] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[] CR2: 00007fffd2db5000 CR3: 000000002b08f000 CR4: 00000000000006f0
Fixes: af9b028e270fd ("tipc: make media xmit call outside node spinlock context")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Signed-off-by: Hoang Le <hoang.h.le@dektech.com.au>
Link: https://lore.kernel.org/r/20210108071337.3598-1-hoang.h.le@dektech.com.au
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/tipc/link.c')
| -rw-r--r-- | net/tipc/link.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/net/tipc/link.c b/net/tipc/link.c index 6ae2140eb4f7..a6a694b78927 100644 --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -1030,7 +1030,6 @@ void tipc_link_reset(struct tipc_link *l) int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list, struct sk_buff_head *xmitq) { - struct tipc_msg *hdr = buf_msg(skb_peek(list)); struct sk_buff_head *backlogq = &l->backlogq; struct sk_buff_head *transmq = &l->transmq; struct sk_buff *skb, *_skb; @@ -1038,13 +1037,18 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list, u16 ack = l->rcv_nxt - 1; u16 seqno = l->snd_nxt; int pkt_cnt = skb_queue_len(list); - int imp = msg_importance(hdr); unsigned int mss = tipc_link_mss(l); unsigned int cwin = l->window; unsigned int mtu = l->mtu; + struct tipc_msg *hdr; bool new_bundle; int rc = 0; + int imp; + + if (pkt_cnt <= 0) + return 0; + hdr = buf_msg(skb_peek(list)); if (unlikely(msg_size(hdr) > mtu)) { pr_warn("Too large msg, purging xmit list %d %d %d %d %d!\n", skb_queue_len(list), msg_user(hdr), @@ -1053,6 +1057,7 @@ int tipc_link_xmit(struct tipc_link *l, struct sk_buff_head *list, return -EMSGSIZE; } + imp = msg_importance(hdr); /* Allow oversubscription of one data msg per source at congestion */ if (unlikely(l->backlog[imp].len >= l->backlog[imp].limit)) { if (imp == TIPC_SYSTEM_IMPORTANCE) { |