CVE-2022-50816
Fecha de publicación:
30/12/2025
*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br />
<br />
ipv6: ensure sane device mtu in tunnels<br />
<br />
Another syzbot report [1] with no reproducer hints<br />
at a bug in ip6_gre tunnel (dev:ip6gretap0)<br />
<br />
Since ipv6 mcast code makes sure to read dev->mtu once<br />
and applies a sanity check on it (see commit b9b312a7a451<br />
"ipv6: mcast: better catch silly mtu values"), a remaining<br />
possibility is that a layer is able to set dev->mtu to<br />
an underflowed value (high order bit set).<br />
<br />
This could happen indeed in ip6gre_tnl_link_config_route(),<br />
ip6_tnl_link_config() and ipip6_tunnel_bind_dev()<br />
<br />
Make sure to sanitize mtu value in a local variable before<br />
it is written once on dev->mtu, as lockless readers could<br />
catch wrong temporary value.<br />
<br />
[1]<br />
skbuff: skb_over_panic: text:ffff80000b7a2f38 len:40 put:40 head:ffff000149dcf200 data:ffff000149dcf2b0 tail:0xd8 end:0xc0 dev:ip6gretap0<br />
------------[ cut here ]------------<br />
kernel BUG at net/core/skbuff.c:120<br />
Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP<br />
Modules linked in:<br />
CPU: 1 PID: 10241 Comm: kworker/1:1 Not tainted 6.0.0-rc7-syzkaller-18095-gbbed346d5a96 #0<br />
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/30/2022<br />
Workqueue: mld mld_ifc_work<br />
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)<br />
pc : skb_panic+0x4c/0x50 net/core/skbuff.c:116<br />
lr : skb_panic+0x4c/0x50 net/core/skbuff.c:116<br />
sp : ffff800020dd3b60<br />
x29: ffff800020dd3b70 x28: 0000000000000000 x27: ffff00010df2a800<br />
x26: 00000000000000c0 x25: 00000000000000b0 x24: ffff000149dcf200<br />
x23: 00000000000000c0 x22: 00000000000000d8 x21: ffff80000b7a2f38<br />
x20: ffff00014c2f7800 x19: 0000000000000028 x18: 00000000000001a9<br />
x17: 0000000000000000 x16: ffff80000db49158 x15: ffff000113bf1a80<br />
x14: 0000000000000000 x13: 00000000ffffffff x12: ffff000113bf1a80<br />
x11: ff808000081c0d5c x10: 0000000000000000 x9 : 73f125dc5c63ba00<br />
x8 : 73f125dc5c63ba00 x7 : ffff800008161d1c x6 : 0000000000000000<br />
x5 : 0000000000000080 x4 : 0000000000000001 x3 : 0000000000000000<br />
x2 : ffff0001fefddcd0 x1 : 0000000100000000 x0 : 0000000000000089<br />
Call trace:<br />
skb_panic+0x4c/0x50 net/core/skbuff.c:116<br />
skb_over_panic net/core/skbuff.c:125 [inline]<br />
skb_put+0xd4/0xdc net/core/skbuff.c:2049<br />
ip6_mc_hdr net/ipv6/mcast.c:1714 [inline]<br />
mld_newpack+0x14c/0x270 net/ipv6/mcast.c:1765<br />
add_grhead net/ipv6/mcast.c:1851 [inline]<br />
add_grec+0xa20/0xae0 net/ipv6/mcast.c:1989<br />
mld_send_cr+0x438/0x5a8 net/ipv6/mcast.c:2115<br />
mld_ifc_work+0x38/0x290 net/ipv6/mcast.c:2653<br />
process_one_work+0x2d8/0x504 kernel/workqueue.c:2289<br />
worker_thread+0x340/0x610 kernel/workqueue.c:2436<br />
kthread+0x12c/0x158 kernel/kthread.c:376<br />
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860<br />
Code: 91011400 aa0803e1 a90027ea 94373093 (d4210000)
Gravedad: Pendiente de análisis
Última modificación:
31/12/2025
