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authorHoang Le <hoang.h.le@dektech.com.au>2021-01-08 10:13:37 +0300
committerJakub Kicinski <kuba@kernel.org>2021-01-10 01:44:47 +0300
commitb77413446408fdd256599daf00d5be72b5f3e7c6 (patch)
tree59aff1a858a335503c3cfee12224bc267b4bdab4 /net/tipc/link.c
parent3502bd9b5762154ff11665f3f18f6d7dcc6f781c (diff)
downloadlinux-b77413446408fdd256599daf00d5be72b5f3e7c6.tar.xz
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.c9
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) {