* [PATCH net v2] batman-adv: fix OOB read/write in network-coding decode
@ 2025-08-31 14:56 Stanislav Fort
2025-08-31 15:06 ` Sven Eckelmann
0 siblings, 1 reply; 2+ messages in thread
From: Stanislav Fort @ 2025-08-31 14:56 UTC (permalink / raw)
To: netdev
Cc: Marek Lindner, Simon Wunderlich, Antonio Quartulli,
Sven Eckelmann, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, moderated list:BATMAN ADVANCED,
open list, disclosure, stable
batadv_nc_skb_decode_packet() trusts coded_len and checks only against
skb->len. XOR starts at sizeof(struct batadv_unicast_packet), reducing
payload headroom, and the source skb length is not verified, allowing an
out-of-bounds read and a small out-of-bounds write.
Validate that coded_len fits within the payload area of both destination
and source sk_buffs before XORing.
Fixes: 2df5278b0267 ("batman-adv: network coding - receive coded packets and decode them")
Cc: stable@vger.kernel.org
Reported-by: Stanislav Fort <disclosure@aisle.com>
Signed-off-by: Stanislav Fort <disclosure@aisle.com>
---
net/batman-adv/network-coding.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index 9f56308779cc..af97d077369f 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -1687,7 +1687,12 @@ batadv_nc_skb_decode_packet(struct batadv_priv *bat_priv, struct sk_buff *skb,
coding_len = ntohs(coded_packet_tmp.coded_len);
- if (coding_len > skb->len)
+ /* ensure dst buffer is large enough (payload only) */
+ if (coding_len + h_size > skb->len)
+ return NULL;
+
+ /* ensure src buffer is large enough (payload only) */
+ if (coding_len + h_size > nc_packet->skb->len)
return NULL;
/* Here the magic is reversed:
--
2.39.3 (Apple Git-146)
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net v2] batman-adv: fix OOB read/write in network-coding decode
2025-08-31 14:56 [PATCH net v2] batman-adv: fix OOB read/write in network-coding decode Stanislav Fort
@ 2025-08-31 15:06 ` Sven Eckelmann
0 siblings, 0 replies; 2+ messages in thread
From: Sven Eckelmann @ 2025-08-31 15:06 UTC (permalink / raw)
To: netdev, Stanislav Fort
Cc: Sven Eckelmann, Marek Lindner, Simon Wunderlich,
Antonio Quartulli, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Simon Horman, b.a.t.m.a.n, linux-kernel, disclosure,
stable
On Sun, 31 Aug 2025 16:56:23 +0200, Stanislav Fort wrote:
> batadv_nc_skb_decode_packet() trusts coded_len and checks only against
> skb->len. XOR starts at sizeof(struct batadv_unicast_packet), reducing
> payload headroom, and the source skb length is not verified, allowing an
> out-of-bounds read and a small out-of-bounds write.
>
> Validate that coded_len fits within the payload area of both destination
> and source sk_buffs before XORing.
>
> [...]
Applied, thanks!
[1/1] batman-adv: fix OOB read/write in network-coding decode
https://git.open-mesh.org/linux-merge.git/commit/?h=batadv/net&id=d77b6ff0ce35a6d0b0b7b9581bc3f76d041d4087
Best regards,
--
Sven Eckelmann <sven@narfation.org>
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