We found this bug while fuzzing the device driver. Using and freeing
the dangling pointer buff->skb would cause use-after-free and
double-free.
This bug is triggerable with compromised/malfunctioning devices. We
found the bug with QEMU emulation and tested the patch by emulation.
We did NOT test on a real device.
Attached is the bug report.
BUG: KASAN: double-free or invalid-free in consume_skb+0x6c/0x1c0
Call Trace:
dump_stack+0x76/0xa0
print_address_description.constprop.0+0x16/0x200
? consume_skb+0x6c/0x1c0
kasan_report_invalid_free+0x61/0xa0
? consume_skb+0x6c/0x1c0
__kasan_slab_free+0x15e/0x170
? consume_skb+0x6c/0x1c0
kfree+0x8c/0x230
consume_skb+0x6c/0x1c0
aq_ring_tx_clean+0x5c2/0xa80 [atlantic]
aq_vec_poll+0x309/0x5d0 [atlantic]
? _sub_I_65535_1+0x20/0x20 [atlantic]
? __next_timer_interrupt+0xba/0xf0
net_rx_action+0x363/0xbd0
? call_timer_fn+0x240/0x240
? __switch_to_asm+0x34/0x70
? napi_busy_loop+0x520/0x520
? net_tx_action+0x379/0x720
__do_softirq+0x18c/0x634
? takeover_tasklets+0x5f0/0x5f0
run_ksoftirqd+0x15/0x20
smpboot_thread_fn+0x2f1/0x6b0
? smpboot_unregister_percpu_thread+0x160/0x160
? __kthread_parkme+0x80/0x100
? smpboot_unregister_percpu_thread+0x160/0x160
kthread+0x2b5/0x3b0
? kthread_create_on_node+0xd0/0xd0
ret_from_fork+0x22/0x40
Reported-by: Brendan Dolan-Gavitt <[email protected]>
Signed-off-by: Zekun Shen <[email protected]>
---
drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index 24122ccda614..81b3756417ec 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -298,13 +298,14 @@ bool aq_ring_tx_clean(struct aq_ring_s *self)
}
}
- if (unlikely(buff->is_eop)) {
+ if (unlikely(buff->is_eop && buff->skb)) {
u64_stats_update_begin(&self->stats.tx.syncp);
++self->stats.tx.packets;
self->stats.tx.bytes += buff->skb->len;
u64_stats_update_end(&self->stats.tx.syncp);
dev_kfree_skb_any(buff->skb);
+ buff->skb = NULL;
}
buff->pa = 0U;
buff->eop_index = 0xffffU;
--
2.25.1
> We found this bug while fuzzing the device driver. Using and freeing
> the dangling pointer buff->skb would cause use-after-free and
> double-free.
>
> This bug is triggerable with compromised/malfunctioning devices. We
> found the bug with QEMU emulation and tested the patch by emulation.
> We did NOT test on a real device.
>
> Attached is the bug report.
>
Reviewed-by: Igor Russkikh <[email protected]>
Thank you for submitting this!
Igor
Hello:
This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:
On Thu, 18 Nov 2021 16:08:02 -0500 you wrote:
> We found this bug while fuzzing the device driver. Using and freeing
> the dangling pointer buff->skb would cause use-after-free and
> double-free.
>
> This bug is triggerable with compromised/malfunctioning devices. We
> found the bug with QEMU emulation and tested the patch by emulation.
> We did NOT test on a real device.
>
> [...]
Here is the summary with links:
- atlantic: fix double-free in aq_ring_tx_clean
https://git.kernel.org/netdev/net/c/6a405f6c372d
You are awesome, thank you!
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