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Eric Dumazet 7b9b1d449a net/smc: fix possible NULL deref in smc_pnet_add_eth()
I missed that @ndev value can be NULL.

I prefer not factorizing this NULL check, and instead
clearly document where a NULL might be expected.

general protection fault, probably for non-canonical address 0xdffffc00000000ba: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000005d0-0x00000000000005d7]
CPU: 0 PID: 19875 Comm: syz-executor.2 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__lock_acquire+0xd7a/0x5470 kernel/locking/lockdep.c:4897
Code: 14 0e 41 bf 01 00 00 00 0f 86 c8 00 00 00 89 05 5c 20 14 0e e9 bd 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 9f 2e 00 00 49 81 3e 20 c5 1a 8f 0f 84 52 f3 ff
RSP: 0018:ffffc900057071d0 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: 1ffff92000ae0e65 RCX: 1ffff92000ae0e4c
RDX: 00000000000000ba RSI: 0000000000000000 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: fffffbfff1b24ae2 R11: 000000000008808a R12: 0000000000000000
R13: ffff888040ca4000 R14: 00000000000005d0 R15: 0000000000000000
FS:  00007fbd683e0700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2be22000 CR3: 0000000013fea000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 lock_acquire kernel/locking/lockdep.c:5637 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
 ref_tracker_alloc+0x182/0x440 lib/ref_tracker.c:84
 netdev_tracker_alloc include/linux/netdevice.h:3859 [inline]
 smc_pnet_add_eth net/smc/smc_pnet.c:372 [inline]
 smc_pnet_enter net/smc/smc_pnet.c:492 [inline]
 smc_pnet_add+0x49a/0x14d0 net/smc/smc_pnet.c:555
 genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
 genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
 genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
 netlink_unicast+0x539/0x7e0 net/netlink/af_netlink.c:1343
 netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1919
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:725
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2413
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2467
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2496
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: b60645248a ("net/smc: add net device tracker to struct smc_pnetentry")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-12 14:45:29 +00:00
Documentation Device properties framework updates for 5.17-rc1 2022-01-10 20:48:19 -08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch Power management updates for 5.17-rc1 2022-01-10 20:34:00 -08:00
block block-5.16-2021-12-19 2021-12-19 12:38:53 -08:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto lib/crypto: blake2s: include as built-in 2022-01-07 00:25:25 +01:00
drivers net: ipa: prevent concurrent replenish 2022-01-12 14:39:53 +00:00
fs Networking changes for 5.17. 2022-01-10 19:06:09 -08:00
include net: sched: do not allocate a tracker in tcf_exts_init() 2022-01-11 20:40:16 -08:00
init Power management updates for 5.17-rc1 2022-01-10 20:34:00 -08:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-11-20 10:35:54 -08:00
kernel Power management updates for 5.17-rc1 2022-01-10 20:34:00 -08:00
lib ref_tracker: use __GFP_NOFAIL more carefully 2022-01-12 14:29:50 +00:00
mm slab changes for 5.17 2022-01-10 11:58:12 -08:00
net net/smc: fix possible NULL deref in smc_pnet_add_eth() 2022-01-12 14:45:29 +00:00
samples Networking changes for 5.17. 2022-01-10 19:06:09 -08:00
scripts recordmcount.pl: fix typo in s390 mcount regex 2021-12-24 10:20:12 +01:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 2021-12-31 14:35:40 +00:00
sound sound fixes for 5.16-rc7 2021-12-23 09:55:58 -08:00
tools Thermal control updates for 5.17-rc1 2022-01-10 20:43:54 -08:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt KVM: downgrade two BUG_ONs to WARN_ON_ONCE 2021-11-26 06:43:28 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap media updates for v5.17-rc1 2022-01-10 18:55:43 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Device properties framework updates for 5.17-rc1 2022-01-10 20:48:19 -08:00
Makefile Linux 5.16 2022-01-09 14:55:34 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.