netdev - [PATCH] net/xen-netback: Break build if netback slots > max

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230927082918.197030-1-k.kahurani@gmail.com>
Date: Wed, 27 Sep 2023 11:29:18 +0300
From: David Kahurani <k.kahurani@...il.com>
To: xen-devel@...ts.xenproject.org
Cc: netdev@...r.kernel.org,
	wei.liu@...nel.org,
	paul@....org,
	David Kahurani <k.kahurani@...il.com>
Subject: [PATCH] net/xen-netback: Break build if netback slots > max_skbs + 1

If XEN_NETBK_LEGACY_SLOTS_MAX and MAX_SKB_FRAGS have a difference of
more than 1, with MAX_SKB_FRAGS being the lesser value, it opens up a
path for null-dereference. It was also noted that some distributions
were modifying upstream behaviour in that direction which necessitates
this patch.

Signed-off-by: David Kahurani <k.kahurani@...il.com>
---
 drivers/net/xen-netback/netback.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 88f760a7cbc3..df032e33787f 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1005,6 +1005,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 			break;
 		}
 
+		BUILD_BUG_ON(XEN_NETBK_LEGACY_SLOTS_MAX > MAX_SKB_FRAGS + 1);
 		if (ret >= XEN_NETBK_LEGACY_SLOTS_MAX - 1 && data_len < txreq.size)
 			data_len = txreq.size;
 
-- 
2.25.1