From: Linus Lüssing linus.luessing@c0d3.blue
commit 51c6b429c0c95e67edd1cb0b548c5cf6a6604763 upstream.
Trying to split and transmit a unicast packet in 16 parts will fail for the final fragment: After having sent the 15th one with a frag_packet.no index of 14, we will increase the the index to 15 - and return with an error code immediately, even though one more fragment is due for transmission and allowed.
Fixing this issue by moving the check before incrementing the index.
While at it, adding an unlikely(), because the check is actually more of an assertion.
Fixes: ee75ed88879a ("batman-adv: Fragment and send skbs larger than mtu") Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de Signed-off-by: Sven Eckelmann sven@narfation.org --- net/batman-adv/fragmentation.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index 8605e3c7958d..9751b207b01f 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -480,6 +480,10 @@ bool batadv_frag_send_packet(struct sk_buff *skb,
/* Eat and send fragments from the tail of skb */ while (skb->len > max_fragment_size) { + /* The initial check in this function should cover this case */ + if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1) + goto out_err; + skb_fragment = batadv_frag_create(skb, &frag_header, mtu); if (!skb_fragment) goto out_err; @@ -490,10 +494,6 @@ bool batadv_frag_send_packet(struct sk_buff *skb, batadv_send_skb_packet(skb_fragment, neigh_node->if_incoming, neigh_node->addr); frag_header.no++; - - /* The initial check in this function should cover this case */ - if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1) - goto out_err; }
/* Make room for the fragment header. */