diff mbox series

[net,v2] tipc: fix NULL deref in tipc_link_xmit()

Message ID 20210108071337.3598-1-hoang.h.le@dektech.com.au (mailing list archive)
State Accepted
Commit b77413446408fdd256599daf00d5be72b5f3e7c6
Delegated to: Netdev Maintainers
Headers show
Series [net,v2] tipc: fix NULL deref in tipc_link_xmit() | expand

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netdev/subject_prefix success Link
netdev/cc_maintainers warning 3 maintainers not CCed: kuba@kernel.org tipc-discussion@lists.sourceforge.net davem@davemloft.net
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 43 this patch: 43
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 33 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 35 this patch: 35
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Hoang Huu Le Jan. 8, 2021, 7:13 a.m. UTC 
From: Hoang Le <hoang.h.le@dektech.com.au>

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>
--
v2: add 'Fixes' tag
---
 net/tipc/link.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Jan. 10, 2021, 12:20 a.m. UTC | #1 
Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Fri,  8 Jan 2021 14:13:37 +0700 you wrote:
> From: Hoang Le <hoang.h.le@dektech.com.au>
> 
> 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
> 
> [...]

Here is the summary with links:
  - [net,v2] tipc: fix NULL deref in tipc_link_xmit()
    https://git.kernel.org/netdev/net/c/b77413446408

You are awesome, thank you!
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diff mbox series

Patch

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) {