[PATCH 5.4 204/367] igmp: limit igmpv3_newpack() packet size to IP_MAX_MTU

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


5.4-stable review patch.  If anyone has any objections, please let me know.


From: Eric Dumazet <edumazet@xxxxxxxxxx>

commit c3b704d4a4a265660e665df51b129e8425216ed1 upstream.

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@xxxxxxxxxxxxxxxx/
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: David Laight <David.Laight@xxxxxxxxxx>
Cc: Kyle Zeng <zengyhkyle@xxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
 net/ipv4/igmp.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -355,8 +355,9 @@ static struct sk_buff *igmpv3_newpack(st
 	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,

[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux