2024-05-20 14:03:31 +00:00

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{
"id": "CVE-2024-35941",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2024-05-19T11:15:49.823",
"lastModified": "2024-05-20T13:00:04.957",
"vulnStatus": "Awaiting Analysis",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: skbuff: add overflow debug check to pull/push helpers\n\nsyzbot managed to trigger following splat:\nBUG: KASAN: use-after-free in __skb_flow_dissect+0x4a3b/0x5e50\nRead of size 1 at addr ffff888208a4000e by task a.out/2313\n[..]\n __skb_flow_dissect+0x4a3b/0x5e50\n __skb_get_hash+0xb4/0x400\n ip_tunnel_xmit+0x77e/0x26f0\n ipip_tunnel_xmit+0x298/0x410\n ..\n\nAnalysis shows that the skb has a valid ->head, but bogus ->data\npointer.\n\nskb->data gets its bogus value via the neigh layer, which does:\n\n1556 __skb_pull(skb, skb_network_offset(skb));\n\n... and the skb was already dodgy at this point:\n\nskb_network_offset(skb) returns a negative value due to an\nearlier overflow of skb->network_header (u16). __skb_pull thus\n\"adjusts\" skb->data by a huge offset, pointing outside skb->head\narea.\n\nAllow debug builds to splat when we try to pull/push more than\nINT_MAX bytes.\n\nAfter this, the syzkaller reproducer yields a more precise splat\nbefore the flow dissector attempts to read off skb->data memory:\n\nWARNING: CPU: 5 PID: 2313 at include/linux/skbuff.h:2653 neigh_connected_output+0x28e/0x400\n ip_finish_output2+0xb25/0xed0\n iptunnel_xmit+0x4ff/0x870\n ipgre_xmit+0x78e/0xbb0"
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/1b2b26595bb09febf14c5444c873ac4ec90a5a77",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/219eee9c0d16f1b754a8b85275854ab17df0850a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/8af60bb2b215f478b886f1d6d302fefa7f0b917d",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/fff05b2b004d9a8a2416d08647f3dc9068e357c8",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}