416baaa9-dc9f-4396-8d5f-8c081fb06d67CVE-2024-26635CVE-2024-26635
In the Linux kernel, the following vulnerability has been resolved:
llc: Drop support for ETH_P_TR_802_2.
syzbot reported an uninit-value bug below. [0]
llc supports ETH_P_802_2 (0x0004) and used to support ETH_P_TR_802_2
(0x0011), and syzbot abused the latter to trigger the bug.
write$tun(r0, &(0x7f0000000040)={@val={0x0, 0x11}, @val, @mpls={[], @llc={@snap={0xaa, 0x1, ‘)’, “90e5dd”}}}}, 0x16)
llc_conn_handler() initialises local variables {saddr,daddr}.mac
based on skb in llc_pdu_decode_sa()/llc_pdu_decode_da() and passes
them to __llc_lookup().
However, the initialisation is done only when skb->protocol is
htons(ETH_P_802_2), otherwise, __llc_lookup_established() and
__llc_lookup_listener() will read garbage.
The missing initialisation existed prior to commit 211ed865108e
(“net: delete all instances of special processing for token ring”).
It removed the part to kick out the token ring stuff but forgot to
close the door allowing ETH_P_TR_802_2 packets to sneak into llc_rcv().
Let’s remove llc_tr_packet_type and complete the deprecation.
[0]:
BUG: KMSAN: uninit-value in __llc_lookup_established+0xe9d/0xf90
__llc_lookup_established+0xe9d/0xf90
__llc_lookup net/llc/llc_conn.c:611 [inline]
llc_conn_handler+0x4bd/0x1360 net/llc/llc_conn.c:791
llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206
__netif_receive_skb_one_core net/core/dev.c:5527 [inline]
__netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5641
netif_receive_skb_internal net/core/dev.c:5727 [inline]
netif_receive_skb+0x58/0x660 net/core/dev.c:5786
tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555
tun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002
tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
call_write_iter include/linux/fs.h:2020 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x8ef/0x1490 fs/read_write.c:584
ksys_write+0x20f/0x4c0 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__x64_sys_write+0x93/0xd0 fs/read_write.c:646
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
Local variable daddr created at:
llc_conn_handler+0x53/0x1360 net/llc/llc_conn.c:783
llc_rcv+0xfbb/0x14a0 net/llc/llc_input.c:206
CPU: 1 PID: 5004 Comm: syz-executor994 Not tainted 6.6.0-syzkaller-14500-g1c41041124bd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
Affected configurations
| Vendor | Product | Version | CPE |
|---|---|---|---|
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | * | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
CNA Affected
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"include/net/llc_pdu.h",
"net/llc/llc_core.c"
],
"versions": [
{
"version": "211ed865108e",
"lessThan": "165ad1e22779",
"status": "affected",
"versionType": "git"
},
{
"version": "211ed865108e",
"lessThan": "b8e8838f82f3",
"status": "affected",
"versionType": "git"
},
{
"version": "211ed865108e",
"lessThan": "9ccdef19cf94",
"status": "affected",
"versionType": "git"
},
{
"version": "211ed865108e",
"lessThan": "c0fe2fe7a5a2",
"status": "affected",
"versionType": "git"
},
{
"version": "211ed865108e",
"lessThan": "660c3053d992",
"status": "affected",
"versionType": "git"
},
{
"version": "211ed865108e",
"lessThan": "f1f34a515fb1",
"status": "affected",
"versionType": "git"
},
{
"version": "211ed865108e",
"lessThan": "df57fc2f2abf",
"status": "affected",
"versionType": "git"
},
{
"version": "211ed865108e",
"lessThan": "e3f9bed9bee2",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"include/net/llc_pdu.h",
"net/llc/llc_core.c"
],
"versions": [
{
"version": "3.5",
"status": "affected"
},
{
"version": "0",
"lessThan": "3.5",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "4.19.307",
"lessThanOrEqual": "4.19.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.4.269",
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.10.210",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.15.149",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.1.76",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.15",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.7.3",
"lessThanOrEqual": "6.7.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.8",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]References
git.kernel.org/stable/c/165ad1e22779685c3ed3dd349c6c4c632309cc62
git.kernel.org/stable/c/660c3053d992b68fee893a0e9ec9159228cffdc6
git.kernel.org/stable/c/9ccdef19cf9497c2803b005369668feb91cacdfd
git.kernel.org/stable/c/b8e8838f82f332ae80c643dbb1ca4418d0628097
git.kernel.org/stable/c/c0fe2fe7a5a291dfcf6dc64301732c8d3dc6a828
git.kernel.org/stable/c/df57fc2f2abf548aa889a36ab0bdcc94a75399dc
git.kernel.org/stable/c/e3f9bed9bee261e3347131764e42aeedf1ffea61
git.kernel.org/stable/c/f1f34a515fb1e25e85dee94f781e7869ae351fb8
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