CVE-2024-26633

In the Linux kernel, the following vulnerability has been resolved:
ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()
syzbot pointed out [1] that NEXTHDR_FRAGMENT handling is broken. Reading
frag_off can only be done if we pulled enough bytes to skb->head. Currently
we might access garbage. [1] BUG: KMSAN: uninit-value in
ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0 ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline] xmit_one
net/core/dev.c:3548 [inline] dev_hard_start_xmit+0x247/0xa10
net/core/dev.c:3564 __dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592 neigh_output
include/net/neighbour.h:542 [inline] ip6_finish_output2+0x23a9/0x2b30
net/ipv6/ip6_output.c:137 ip6_finish_output+0x855/0x12b0
net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303
[inline] ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243 dst_output
include/net/dst.h:451 [inline] ip6_local_out+0xe9/0x140
net/ipv6/output_core.c:155 ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920 inet_sendmsg+0x105/0x190
net/ipv4/af_inet.c:847 sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x9c2/0xd60
net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline] __do_sys_sendmsg net/socket.c:2676
[inline] __se_sys_sendmsg net/socket.c:2674 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2674 do_syscall_x64
arch/x86/entry/common.c:52 [inline] do_syscall_64+0x44/0x110
arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Uninit
was created at: slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
slab_alloc_node mm/slub.c:3478 [inline] __kmem_cache_alloc_node+0x5c9/0x970
mm/slub.c:3517 __do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc_node_track_caller+0x118/0x3c0 mm/slab_common.c:1027
kmalloc_reserve+0x249/0x4a0 net/core/skbuff.c:582
pskb_expand_head+0x226/0x1a00 net/core/skbuff.c:2098
__pskb_pull_tail+0x13b/0x2310 net/core/skbuff.c:2655 pskb_may_pull_reason
include/linux/skbuff.h:2673 [inline] pskb_may_pull
include/linux/skbuff.h:2681 [inline] ip6_tnl_parse_tlv_enc_lim+0x901/0xbb0
net/ipv6/ip6_tunnel.c:408 ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326
[inline] ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline] xmit_one
net/core/dev.c:3548 [inline] dev_hard_start_xmit+0x247/0xa10
net/core/dev.c:3564 __dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592 neigh_output
include/net/neighbour.h:542 [inline] ip6_finish_output2+0x23a9/0x2b30
net/ipv6/ip6_output.c:137 ip6_finish_output+0x855/0x12b0
net/ipv6/ip6_output.c:222 NF_HOOK_COND include/linux/netfilter.h:303
[inline] ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243 dst_output
include/net/dst.h:451 [inline] ip6_local_out+0xe9/0x140
net/ipv6/output_core.c:155 ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920 inet_sendmsg+0x105/0x190
net/ipv4/af_inet.c:847 sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x9c2/0xd60
net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638
__sys_sendmsg net/socket.c:2667 [inline] __do_sys_sendms —truncated—

Notes