[syzbot] [net?] WARNING in dev_index_reserve

[syzbot]

syzbot has bisected this issue to:

commit 956db0a13b47df7f3d6d624394e602e8bf9b057e
Author: Jakub Kicinski <ku...@kernel.org>
Date: Mon Aug 14 20:56:25 2023 +0000

net: warn about attempts to register negative ifindex

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17f68f03a80000
start commit: 950fe35831af Merge branch 'ipv6-expired-routes'
git tree: net-next
final oops: https://syzkaller.appspot.com/x/report.txt?x=140e8f03a80000
console output: https://syzkaller.appspot.com/x/log.txt?x=100e8f03a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=fe63ad15dded26b6
dashboard link: https://syzkaller.appspot.com/bug?extid=5ba06978f34abb058571
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11be0117a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14950727a80000

Reported-by: syzbot+5ba069...@syzkaller.appspotmail.com
Fixes: 956db0a13b47 ("net: warn about attempts to register negative ifindex")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Hillf Danton]

On Wed, 16 Aug 2023 12:07:57 -0700
> HEAD commit: 950fe35831af Merge branch 'ipv6-expired-routes'
> git tree: net-next
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14950727a80000

Check if if_index is valid.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 950fe35831af

--- x/net/core/rtnetlink.c
+++ y/net/core/rtnetlink.c
@@ -3458,6 +3458,10 @@ static int rtnl_newlink_create(struct sk
link_net = NULL;
}

+ if (ifm->ifi_index > INT_MAX) {
+ err = -EINVAL;
+ goto out;
+ }
dev = rtnl_create_link(link_net ? : dest_net, ifname,
name_assign_type, ops, tb, extack);
if (IS_ERR(dev)) {
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in dev_index_reserve

netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5446 at net/core/dev.c:9593 dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Modules linked in:
CPU: 1 PID: 5446 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-01605-g950fe35831af-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Code: 00 31 d2 4d 8d 45 50 b9 ff ff ff 7f 48 8d 74 24 20 e8 f2 05 02 02 4c 89 e7 89 c3 e8 48 01 11 02 e9 48 ff ff ff e8 5e 1a 5e f9 <0f> 0b bb ea ff ff ff e9 52 ff ff ff e8 cd 4f 0d 02 66 66 2e 0f 1f
RSP: 0018:ffffc90005a4efa8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000000
RDX: ffff888028b83b80 RSI: ffffffff88280632 RDI: 0000000000000005
RBP: 1ffff92000b49df5 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffff R11: ffffffff8a40008b R12: ffff88802c1f6010
R13: ffff88807bd89d40 R14: ffff88802c1f6000 R15: ffff88802c1f60f8
FS: 00007ffad37b86c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000040 CR3: 000000002c10f000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
register_netdevice+0x69a/0x1490 net/core/dev.c:10081
veth_newlink+0x521/0xa50 drivers/net/veth.c:1938
rtnl_newlink_create net/core/rtnetlink.c:3475 [inline]
__rtnl_newlink+0x115e/0x18c0 net/core/rtnetlink.c:3692
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3705
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6431
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2545
netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
netlink_unicast+0x536/0x810 net/netlink/af_netlink.c:1368
netlink_sendmsg+0x93c/0xe40 net/netlink/af_netlink.c:1910
sock_sendmsg_nosec net/socket.c:728 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:751
____sys_sendmsg+0x6ac/0x940 net/socket.c:2514
___sys_sendmsg+0x135/0x1d0 net/socket.c:2568
__sys_sendmsg+0x117/0x1e0 net/socket.c:2597
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7ffad2a7cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffad37b80c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffad2b9bf80 RCX: 00007ffad2a7cae9
RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00007ffad2ac847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007ffad2b9bf80 R15: 00007ffc858ed2f8
</TASK>


Tested on:

commit: 950fe358 Merge branch 'ipv6-expired-routes'
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1341e265a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fe63ad15dded26b6
dashboard link: https://syzkaller.appspot.com/bug?extid=5ba06978f34abb058571

compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=1224279ba80000

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 950fe35831af Merge branch 'ipv6-expired-routes'
git tree: net-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13158a4ba80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fe63ad15dded26b6
dashboard link: https://syzkaller.appspot.com/bug?extid=5ba06978f34abb058571
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11be0117a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14950727a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d3d4f3ce986f/disk-950fe358.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d5afd9c7f284/vmlinux-950fe358.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1a203c65f0ae/bzImage-950fe358.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5ba069...@syzkaller.appspotmail.com

netlink: 24 bytes leftover after parsing attributes in process `syz-executor252'.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5027 at net/core/dev.c:9593 dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Modules linked in:
CPU: 0 PID: 5027 Comm: syz-executor252 Not tainted 6.5.0-rc5-syzkaller-01605-g950fe35831af #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Code: 00 31 d2 4d 8d 45 50 b9 ff ff ff 7f 48 8d 74 24 20 e8 f2 05 02 02 4c 89 e7 89 c3 e8 48 01 11 02 e9 48 ff ff ff e8 5e 1a 5e f9 <0f> 0b bb ea ff ff ff e9 52 ff ff ff e8 cd 4f 0d 02 66 66 2e 0f 1f

RSP: 0018:ffffc90003a2efa8 EFLAGS: 00010293

RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000000

RDX: ffff88807d940000 RSI: ffffffff88280632 RDI: 0000000000000005
RBP: 1ffff92000745df5 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffff R11: ffffffff8a40008b R12: ffff88823bd20010
R13: ffffffff924d1180 R14: ffff88823bd20000 R15: ffff88823bd200f8
FS: 00005555573a0380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 000055feb9a33020 CR3: 000000001eaea000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
register_netdevice+0x69a/0x1490 net/core/dev.c:10081
veth_newlink+0x521/0xa50 drivers/net/veth.c:1938

rtnl_newlink_create net/core/rtnetlink.c:3471 [inline]
__rtnl_newlink+0x115e/0x18c0 net/core/rtnetlink.c:3688
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3701
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6427

netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2545
netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
netlink_unicast+0x536/0x810 net/netlink/af_netlink.c:1368
netlink_sendmsg+0x93c/0xe40 net/netlink/af_netlink.c:1910
sock_sendmsg_nosec net/socket.c:728 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:751
____sys_sendmsg+0x6ac/0x940 net/socket.c:2514
___sys_sendmsg+0x135/0x1d0 net/socket.c:2568
__sys_sendmsg+0x117/0x1e0 net/socket.c:2597
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7ff9080bb329
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc3ff5b078 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ffc3ff5b248 RCX: 00007ff9080bb329

RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000003

RBP: 00007ff90812e610 R08: 0000000000000000 R09: 00007ffc3ff5b248
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc3ff5b238 R14: 0000000000000001 R15: 0000000000000001
</TASK>


---
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syzbot will keep track of this issue. See:
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If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite bug's subsystems, reply with:
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If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Hillf Danton]

On Wed, 16 Aug 2023 12:07:57 -0700

> HEAD commit: 950fe35831af Merge branch 'ipv6-expired-routes'
> git tree: net-next

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14950727a80000

Check if if_index is valid.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 950fe35831af

--- x/net/core/rtnetlink.c
+++ y/net/core/rtnetlink.c

@@ -3466,6 +3466,11 @@ static int rtnl_newlink_create(struct sk
}

dev->ifindex = ifm->ifi_index;
+ if (dev->ifindex > INT_MAX) {
+ err = -EINVAL;
+ free_netdev(dev);
+ goto out;
+ }

if (ops->newlink)
err = ops->newlink(link_net ? : net, dev, tb, data, extack);
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in dev_index_reserve

netlink: 24 bytes leftover after parsing attributes in process `syz-executor.0'.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5448 at net/core/dev.c:9593 dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Modules linked in:
CPU: 0 PID: 5448 Comm: syz-executor.0 Not tainted 6.5.0-rc5-syzkaller-01605-g950fe35831af-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:dev_index_reserve+0x1a2/0x1c0 net/core/dev.c:9593
Code: 00 31 d2 4d 8d 45 50 b9 ff ff ff 7f 48 8d 74 24 20 e8 f2 05 02 02 4c 89 e7 89 c3 e8 48 01 11 02 e9 48 ff ff ff e8 5e 1a 5e f9 <0f> 0b bb ea ff ff ff e9 52 ff ff ff e8 cd 4f 0d 02 66 66 2e 0f 1f

RSP: 0018:ffffc9000623efa8 EFLAGS: 00010293

RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000000000000

RDX: ffff888029d59dc0 RSI: ffffffff88280632 RDI: 0000000000000005
RBP: 1ffff92000c47df5 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffff R11: ffffffff8a40008b R12: ffff88802cd68010
R13: ffff888024e91d40 R14: ffff88802cd68000 R15: ffff88802cd680f8
FS: 00007f5beb1a96c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000020000040 CR3: 0000000028632000 CR4: 00000000003506f0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
register_netdevice+0x69a/0x1490 net/core/dev.c:10081
veth_newlink+0x521/0xa50 drivers/net/veth.c:1938

rtnl_newlink_create net/core/rtnetlink.c:3476 [inline]
__rtnl_newlink+0x115e/0x18c0 net/core/rtnetlink.c:3693
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3706
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6432

netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2545
netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
netlink_unicast+0x536/0x810 net/netlink/af_netlink.c:1368
netlink_sendmsg+0x93c/0xe40 net/netlink/af_netlink.c:1910
sock_sendmsg_nosec net/socket.c:728 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:751
____sys_sendmsg+0x6ac/0x940 net/socket.c:2514
___sys_sendmsg+0x135/0x1d0 net/socket.c:2568
__sys_sendmsg+0x117/0x1e0 net/socket.c:2597
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f5bea47cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5beb1a90c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f5bea59bf80 RCX: 00007f5bea47cae9

RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000003

RBP: 00007f5bea4c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f5bea59bf80 R15: 00007ffd991b5b58

</TASK>


Tested on:

commit: 950fe358 Merge branch 'ipv6-expired-routes'
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=16e89097a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fe63ad15dded26b6
dashboard link: https://syzkaller.appspot.com/bug?extid=5ba06978f34abb058571
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17974440680000