diff options
authorEric Dumazet <edumazet@google.com>2018-07-30 21:50:29 -0700
committerDavid S. Miller <davem@davemloft.net>2018-07-31 14:41:29 -0700
commit4672694bd4f1aebdab0ad763ae4716e89cb15221 (patch)
parent56e2c94f055d328f5f6b0a5c1721cca2f2d4e0a1 (diff)
ipv4: frags: handle possible skb truesize change
ip_frag_queue() might call pskb_pull() on one skb that is already in the fragment queue. We need to take care of possible truesize change, or we might have an imbalance of the netns frags memory usage. IPv6 is immune to this bug, because RFC5722, Section 4, amended by Errata ID 3089 states : When reassembling an IPv6 datagram, if one or more its constituent fragments is determined to be an overlapping fragment, the entire datagram (and any constituent fragments) MUST be silently discarded. Fixes: 158f323b9868 ("net: adjust skb->truesize in pskb_expand_head()") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 5 insertions, 0 deletions
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 8e9528ebaa8e..d14d741fb05e 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -383,11 +383,16 @@ found:
int i = end - next->ip_defrag_offset; /* overlap is 'i' bytes */
if (i < next->len) {
+ int delta = -next->truesize;
/* Eat head of the next overlapped fragment
* and leave the loop. The next ones cannot overlap.
if (!pskb_pull(next, i))
goto err;
+ delta += next->truesize;
+ if (delta)
+ add_frag_mem_limit(qp->q.net, delta);
next->ip_defrag_offset += i;
qp->q.meat -= i;
if (next->ip_summed != CHECKSUM_UNNECESSARY)