diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2024-01-19 02:55:15 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-01-20 06:30:09 +0100 |
| commit | e3f9bed9bee261e3347131764e42aeedf1ffea61 (patch) | |
| tree | 09474ab4a291f6c5676b7c8365905a798a99b311 /include | |
| parent | llc: make llc_ui_sendmsg() more robust against bonding changes (diff) | |
| download | linux-e3f9bed9bee261e3347131764e42aeedf1ffea61.tar.xz linux-e3f9bed9bee261e3347131764e42aeedf1ffea61.zip | |
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
Fixes: 211ed865108e ("net: delete all instances of special processing for token ring")
Reported-by: syzbot+b5ad66046b913bc04c6f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b5ad66046b913bc04c6f
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240119015515.61898-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/llc_pdu.h | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/include/net/llc_pdu.h b/include/net/llc_pdu.h index 7e73f8e5e497..1d55ba7c45be 100644 --- a/include/net/llc_pdu.h +++ b/include/net/llc_pdu.h @@ -262,8 +262,7 @@ static inline void llc_pdu_header_init(struct sk_buff *skb, u8 type, */ static inline void llc_pdu_decode_sa(struct sk_buff *skb, u8 *sa) { - if (skb->protocol == htons(ETH_P_802_2)) - memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN); + memcpy(sa, eth_hdr(skb)->h_source, ETH_ALEN); } /** @@ -275,8 +274,7 @@ static inline void llc_pdu_decode_sa(struct sk_buff *skb, u8 *sa) */ static inline void llc_pdu_decode_da(struct sk_buff *skb, u8 *da) { - if (skb->protocol == htons(ETH_P_802_2)) - memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN); + memcpy(da, eth_hdr(skb)->h_dest, ETH_ALEN); } /** |