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authorEric Dumazet <edumazet@google.com>2023-09-05 04:23:38 +0000
committerDavid S. Miller <davem@davemloft.net>2023-09-05 17:49:40 +0100
commitc3b704d4a4a265660e665df51b129e8425216ed1 (patch)
treecf8d488ca7e6e0133504e5137a218d87436d5c22 /net/ipv4
parentd3287e4038ca4f81e02067ab72d087af7224c68b (diff)
igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU
This is a follow up of commit 915d975b2ffa ("net: deal with integer overflows in kmalloc_reserve()") based on David Laight feedback. Back in 2010, I failed to realize malicious users could set dev->mtu to arbitrary values. This mtu has been since limited to 0x7fffffff but regardless of how big dev->mtu is, it makes no sense for igmpv3_newpack() to allocate more than IP_MAX_MTU and risk various skb fields overflows. Fixes: 57e1ab6eaddc ("igmp: refine skb allocations") Link: https://lore.kernel.org/netdev/d273628df80f45428e739274ab9ecb72@AcuMS.aculab.com/ Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: David Laight <David.Laight@ACULAB.COM> Cc: Kyle Zeng <zengyhkyle@gmail.com> Reviewed-by: Simon Horman <horms@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/igmp.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 0c9e768e5628..418e5fb58fd3 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -353,8 +353,9 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, unsigned int mtu)
struct flowi4 fl4;
int hlen = LL_RESERVED_SPACE(dev);
int tlen = dev->needed_tailroom;
- unsigned int size = mtu;
+ unsigned int size;
+ size = min(mtu, IP_MAX_MTU);
while (1) {
skb = alloc_skb(size + hlen + tlen,
GFP_ATOMIC | __GFP_NOWARN);