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authorSven Eckelmann <sven@narfation.org>2022-04-16 13:51:10 +0200
committerSimon Wunderlich <sw@simonwunderlich.de>2022-04-17 23:41:44 +0200
commita063f2fba3fa633a599253b62561051ac185fa99 (patch)
tree84152e180e209cac5d1a91d81e9a54ef173be576
parent3123109284176b1532874591f7c81f3837bbdc17 (diff)
batman-adv: Don't skb_split skbuffs with frag_list
The receiving interface might have used GRO to receive more fragments than MAX_SKB_FRAGS fragments. In this case, these will not be stored in skb_shinfo(skb)->frags but merged into the frag list. batman-adv relies on the function skb_split to split packets up into multiple smaller packets which are not larger than the MTU on the outgoing interface. But this function cannot handle frag_list entries and is only operating on skb_shinfo(skb)->frags. If it is still trying to split such an skb and xmit'ing it on an interface without support for NETIF_F_FRAGLIST, then validate_xmit_skb() will try to linearize it. But this fails due to inconsistent information. And __pskb_pull_tail will trigger a BUG_ON after skb_copy_bits() returns an error. In case of entries in frag_list, just linearize the skb before operating on it with skb_split(). Reported-by: Felix Kaechele <felix@kaechele.ca> Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Signed-off-by: Sven Eckelmann <sven@narfation.org> Tested-by: Felix Kaechele <felix@kaechele.ca> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
-rw-r--r--net/batman-adv/fragmentation.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index 0899a729a23f..c120c7c6d25f 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -475,6 +475,17 @@ int batadv_frag_send_packet(struct sk_buff *skb,
goto free_skb;
}
+ /* GRO might have added fragments to the fragment list instead of
+ * frags[]. But this is not handled by skb_split and must be
+ * linearized to avoid incorrect length information after all
+ * batman-adv fragments were created and submitted to the
+ * hard-interface
+ */
+ if (skb_has_frag_list(skb) && __skb_linearize(skb)) {
+ ret = -ENOMEM;
+ goto free_skb;
+ }
+
/* Create one header to be copied to all fragments */
frag_header.packet_type = BATADV_UNICAST_FRAG;
frag_header.version = BATADV_COMPAT_VERSION;