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| author | Davide Caratti <dcaratti@redhat.com> | 2021-04-26 17:45:51 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-04-26 22:06:39 +0200 |
| commit | f77bd544a6bbe69aa50d9ed09f13494cf36ff806 (patch) | |
| tree | 9ef9579f193f1f93bda6b0439b32595d06128414 /net/sched | |
| parent | net: Fix typo in comment about ancillary data (diff) | |
| download | linux-f77bd544a6bbe69aa50d9ed09f13494cf36ff806.tar.xz linux-f77bd544a6bbe69aa50d9ed09f13494cf36ff806.zip | |
net/sched: act_ct: fix wild memory access when clearing fragments
while testing re-assembly/re-fragmentation using act_ct, it's possible to
observe a crash like the following one:
KASAN: maybe wild-memory-access in range [0x0001000000000448-0x000100000000044f]
CPU: 50 PID: 0 Comm: swapper/50 Tainted: G S 5.12.0-rc7+ #424
Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.4.3 01/17/2017
RIP: 0010:inet_frag_rbtree_purge+0x50/0xc0
Code: 00 fc ff df 48 89 c3 31 ed 48 89 df e8 a9 7a 38 ff 4c 89 fe 48 89 df 49 89 c6 e8 5b 3a 38 ff 48 8d 7b 40 48 89 f8 48 c1 e8 03 <42> 80 3c 20 00 75 59 48 8d bb d0 00 00 00 4c 8b 6b 40 48 89 f8 48
RSP: 0018:ffff888c31449db8 EFLAGS: 00010203
RAX: 0000200000000089 RBX: 000100000000040e RCX: ffffffff989eb960
RDX: 0000000000000140 RSI: ffffffff97cfb977 RDI: 000100000000044e
RBP: 0000000000000900 R08: 0000000000000000 R09: ffffed1186289350
R10: 0000000000000003 R11: ffffed1186289350 R12: dffffc0000000000
R13: 000100000000040e R14: 0000000000000000 R15: ffff888155e02160
FS: 0000000000000000(0000) GS:ffff888c31440000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005600cb70a5b8 CR3: 0000000a2c014005 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
inet_frag_destroy+0xa9/0x150
call_timer_fn+0x2d/0x180
run_timer_softirq+0x4fe/0xe70
__do_softirq+0x197/0x5a0
irq_exit_rcu+0x1de/0x200
sysvec_apic_timer_interrupt+0x6b/0x80
</IRQ>
when act_ct temporarily stores an IP fragment, restoring the skb qdisc cb
results in putting random data in FRAG_CB(), and this causes those "wild"
memory accesses later, when the rbtree is purged. Never overwrite the skb
cb in case tcf_ct_handle_fragments() returns -EINPROGRESS.
Fixes: ae372cb1750f ("net/sched: act_ct: fix restore the qdisc_skb_cb after defrag")
Fixes: 7baf2429a1a9 ("net/sched: cls_flower add CT_FLAGS_INVALID flag support")
Reported-by: Shuang Li <shuali@redhat.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/act_ct.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index 16e888a9601d..48fdf7293dea 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -732,7 +732,8 @@ static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb, #endif } - *qdisc_skb_cb(skb) = cb; + if (err != -EINPROGRESS) + *qdisc_skb_cb(skb) = cb; skb_clear_hash(skb); skb->ignore_df = 1; return err; @@ -967,7 +968,7 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a, err = tcf_ct_handle_fragments(net, skb, family, p->zone, &defrag); if (err == -EINPROGRESS) { retval = TC_ACT_STOLEN; - goto out; + goto out_clear; } if (err) goto drop; @@ -1030,7 +1031,6 @@ do_nat: out_push: skb_push_rcsum(skb, nh_ofs); -out: qdisc_skb_cb(skb)->post_ct = true; out_clear: tcf_action_update_bstats(&c->common, skb); |