YueHaibing 76c279c7b6 fs/proc/proc_sysctl.c: Fix a NULL pointer dereference ... commit 89189557b47b35683a27c80ee78aef18248eefb4 upstream. Syzkaller report this: sysctl could not get directory: /net//bridge -12 kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN PTI CPU: 1 PID: 7027 Comm: syz-executor.0 Tainted: G C 5.1.0-rc3+ #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 RIP: 0010:__write_once_size include/linux/compiler.h:220 [inline] RIP: 0010:__rb_change_child include/linux/rbtree_augmented.h:144 [inline] RIP: 0010:__rb_erase_augmented include/linux/rbtree_augmented.h:186 [inline] RIP: 0010:rb_erase+0x5f4/0x19f0 lib/rbtree.c:459 Code: 00 0f 85 60 13 00 00 48 89 1a 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 89 f2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 75 0c 00 00 4d 85 ed 4c 89 2e 74 ce 4c 89 ea 48 RSP: 0018:ffff8881bb507778 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: ffff8881f224b5b8 RCX: ffffffff818f3f6a RDX: 000000000000000a RSI: 0000000000000050 RDI: ffff8881f224b568 RBP: 0000000000000000 R08: ffffed10376a0ef4 R09: ffffed10376a0ef4 R10: 0000000000000001 R11: ffffed10376a0ef4 R12: ffff8881f224b558 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f3e7ce13700(0000) GS:ffff8881f7300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd60fbe9398 CR3: 00000001cb55c001 CR4: 00000000007606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: erase_entry fs/proc/proc_sysctl.c:178 [inline] erase_header+0xe3/0x160 fs/proc/proc_sysctl.c:207 start_unregistering fs/proc/proc_sysctl.c:331 [inline] drop_sysctl_table+0x558/0x880 fs/proc/proc_sysctl.c:1631 get_subdir fs/proc/proc_sysctl.c:1022 [inline] __register_sysctl_table+0xd65/0x1090 fs/proc/proc_sysctl.c:1335 br_netfilter_init+0x68/0x1000 [br_netfilter] do_one_initcall+0xbc/0x47d init/main.c:901 do_init_module+0x1b5/0x547 kernel/module.c:3456 load_module+0x6405/0x8c10 kernel/module.c:3804 __do_sys_finit_module+0x162/0x190 kernel/module.c:3898 do_syscall_64+0x9f/0x450 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Modules linked in: br_netfilter(+) backlight comedi(C) hid_sensor_hub max3100 ti_ads8688 udc_core fddi snd_mona leds_gpio rc_streamzap mtd pata_netcell nf_log_common rc_winfast udp_tunnel snd_usbmidi_lib snd_usb_toneport snd_usb_line6 snd_rawmidi snd_seq_device snd_hwdep videobuf2_v4l2 videobuf2_common videodev media videobuf2_vmalloc videobuf2_memops rc_gadmei_rm008z 8250_of smm665 hid_tmff hid_saitek hwmon_vid rc_ati_tv_wonder_hd_600 rc_core pata_pdc202xx_old dn_rtmsg as3722 ad714x_i2c ad714x snd_soc_cs4265 hid_kensington panel_ilitek_ili9322 drm drm_panel_orientation_quirks ipack cdc_phonet usbcore phonet hid_jabra hid extcon_arizona can_dev industrialio_triggered_buffer kfifo_buf industrialio adm1031 i2c_mux_ltc4306 i2c_mux ipmi_msghandler mlxsw_core snd_soc_cs35l34 snd_soc_core snd_pcm_dmaengine snd_pcm snd_timer ac97_bus snd_compress snd soundcore gpio_da9055 uio ecdh_generic mdio_thunder of_mdio fixed_phy libphy mdio_cavium iptable_security iptable_raw iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_filter bpfilter ip6_vti ip_vti ip_gre ipip sit tunnel4 ip_tunnel hsr veth netdevsim vxcan batman_adv cfg80211 rfkill chnl_net caif nlmon dummy team bonding vcan bridge stp llc ip6_gre gre ip6_tunnel tunnel6 tun joydev mousedev ppdev tpm kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel ide_pci_generic piix aes_x86_64 crypto_simd cryptd ide_core glue_helper input_leds psmouse intel_agp intel_gtt serio_raw ata_generic i2c_piix4 agpgart pata_acpi parport_pc parport floppy rtc_cmos sch_fq_codel ip_tables x_tables sha1_ssse3 sha1_generic ipv6 [last unloaded: br_netfilter] Dumping ftrace buffer: (ftrace buffer empty) ---[ end trace 68741688d5fbfe85 ]--- commit 23da9588037e ("fs/proc/proc_sysctl.c: fix NULL pointer dereference in put_links") forgot to handle start_unregistering() case, while header->parent is NULL, it calls erase_header() and as seen in the above syzkaller call trace, accessing &header->parent->root will trigger a NULL pointer dereference. As that commit explained, there is also no need to call start_unregistering() if header->parent is NULL. Link: http://lkml.kernel.org/r/20190409153622.28112-1-yuehaibing@huawei.com Fixes: 23da9588037e ("fs/proc/proc_sysctl.c: fix NULL pointer dereference in put_links") Fixes: 0e47c99d7f ("sysctl: Replace root_list with links between sysctl_table_sets") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reported-by: Hulk Robot <hulkci@huawei.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-05-16 19:44:51 +02:00
..
9p	9p locks: add mount option for lock retry interval	2019-04-27 09:33:58 +02:00
adfs
affs	affs_lookup(): close a race with affs_remove_link()	2018-05-30 07:48:51 +02:00
afs	afs: Fix afs_kill_pages()	2017-12-20 10:04:56 +01:00
autofs4	autofs: fix error return in autofs_fill_super()	2019-03-23 08:44:27 +01:00
befs
bfs	bfs: add sanity check at bfs_fill_super()	2018-12-01 09:46:33 +01:00
btrfs	btrfs: raid56: properly unmap parity page in finish_parity_scrub()	2019-04-03 06:23:26 +02:00
cachefiles	fscache, cachefiles: remove redundant variable 'cache'	2018-12-17 21:55:12 +01:00
ceph	ceph: fix ci->i_head_snapc leak	2019-05-16 19:44:43 +02:00
cifs	cifs: do not attempt cifs operation on smb2+ rename error	2019-05-16 19:44:43 +02:00
coda	coda: fix 'kernel memory exposure attempt' in fsync	2017-11-24 08:32:25 +01:00
configfs	configfs: replace strncpy with memcpy	2018-11-21 09:27:44 +01:00
cramfs	Cramfs: fix abad comparison when wrap-arounds occur	2018-11-21 09:27:37 +01:00
debugfs	debugfs: fix debugfs_rename parameter checking	2019-02-20 10:13:18 +01:00
devpts
dlm	dlm: Don't swamp the CPU with callbacks queued during recovery	2019-02-20 10:13:04 +01:00
ecryptfs	do d_instantiate/unlock_new_inode combinations safely	2018-05-30 07:48:52 +02:00
efivarfs
efs
exofs	fs/exofs: fix potential memory leak in mount option parsing	2018-11-27 16:08:00 +01:00
exportfs	exportfs: do not read dentry after free	2018-12-17 21:55:10 +01:00
ext2	ext2: Fix underflow in ext2_max_size()	2019-03-23 08:44:36 +01:00
ext4	ext4: prohibit fstrim in norecovery mode	2019-04-27 09:33:58 +02:00
f2fs	f2fs: fix to do sanity check with current segment number	2019-04-27 09:33:58 +02:00
fat	fs/fat/fatent.c: add cond_resched() to fat_count_free_clusters()	2018-11-10 07:41:40 -08:00
freevxfs
fscache	fscache: fix race between enablement and dropping of object	2018-12-17 21:55:11 +01:00
fuse	fuse: handle zero sized retrieve correctly	2019-02-20 10:13:16 +01:00
gfs2	gfs2: Revert "Fix loop in gfs2_rbm_find"	2019-02-06 19:43:07 +01:00
hfs	hfs: do not free node before using	2018-12-17 21:55:12 +01:00
hfsplus	hfsplus: do not free node before using	2018-12-17 21:55:12 +01:00
hostfs
hpfs
hugetlbfs	hugetlbfs: fix races and page leaks during migration	2019-03-23 08:44:23 +01:00
isofs	isofs: fix timestamps beyond 2027	2017-11-30 08:37:20 +00:00
jbd2	jbd2: fix compile warning when using JBUFFER_TRACE	2019-03-23 08:44:37 +01:00
jffs2	jffs2: Fix use of uninitialized delayed_work, lockdep breakage	2019-01-26 09:42:53 +01:00
jfs	jfs: Fix inconsistency between memory allocation and ea_buf->max_size	2018-08-09 12:19:28 +02:00
kernfs	kernfs: Replace strncpy with memcpy	2018-12-13 09:21:29 +01:00
lockd	lockd: fix access beyond unterminated strings in prints	2018-11-21 09:27:36 +01:00
logfs
minix
ncpfs	ncpfs: fix build warning of strncpy	2019-03-23 08:44:21 +01:00
nfs	NFS: Don't recoalesce on error in nfs_pageio_complete_mirror()	2019-03-23 08:44:39 +01:00
nfs_common	lockd: fix "list_add double add" caused by legacy signal interface	2018-02-03 17:04:28 +01:00
nfsd	nfsd: Don't release the callback slot unless it was actually held	2019-05-16 19:44:44 +02:00
nilfs2	do d_instantiate/unlock_new_inode combinations safely	2018-05-30 07:48:52 +02:00
nls
notify	fanotify: fix logic of events on child	2018-04-24 09:32:11 +02:00
ntfs
ocfs2	ocfs2: fix a panic problem caused by o2cb_ctl	2019-04-27 09:33:48 +02:00
omfs
openpromfs
overlayfs	ovl: fix uid/gid when creating over whiteout	2019-04-27 09:33:59 +02:00
proc	fs/proc/proc_sysctl.c: Fix a NULL pointer dereference	2019-05-16 19:44:51 +02:00
pstore	pstore/ram: Do not treat empty buffers as valid	2019-01-26 09:42:53 +01:00
qnx4
qnx6
quota	fs/quota: Fix spectre gadget in do_quotactl	2018-09-09 20:04:36 +02:00
ramfs
reiserfs	reiserfs: propagate errors from fill_with_dentries() properly	2018-11-27 16:08:00 +01:00
romfs	romfs: use different way to generate fsid for BLOCK or MTD	2017-06-17 06:39:38 +02:00
squashfs	squashfs: more metadata hardenings	2018-08-06 16:24:42 +02:00
sysfs	scsi: sysfs: Introduce sysfs_{un,}break_active_protection()	2018-09-05 09:18:40 +02:00
sysv	sysv: return 'err' instead of 0 in __sysv_write_inode	2018-12-17 21:55:09 +01:00
tracefs
ubifs	ubifs: Check for name being NULL while mounting	2018-10-13 09:11:34 +02:00
udf	udf: Fix crash on IO error during truncate	2019-04-03 06:23:14 +02:00
ufs	do d_instantiate/unlock_new_inode combinations safely	2018-05-30 07:48:52 +02:00
xfs	xfs: don't fail when converting shortform attr to long form during ATTR_REPLACE	2019-01-26 09:42:52 +01:00
aio.c	aio: fix spectre gadget in lookup_ioctx	2018-12-21 14:09:50 +01:00
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf.c	binfmt_elf: switch to new creds when switching to new mm	2019-04-27 09:33:53 +02:00
binfmt_elf_fdpic.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c	fs/binfmt_misc.c: do not allow offset overflow	2018-07-03 11:21:26 +02:00
binfmt_script.c	Revert "exec: load_script: don't blindly truncate shebang string"	2019-02-20 10:13:20 +01:00
block_dev.c	fs/block_dev: always invalidate cleancache in invalidate_bdev()	2017-05-20 14:27:01 +02:00
buffer.c	fs: fix guard_bio_eod to check for real EOD errors	2019-04-27 09:33:49 +02:00
char_dev.c
compat.c
compat_binfmt_elf.c	binfmt_elf: compat: avoid unused function warning	2018-02-25 11:03:51 +01:00
compat_ioctl.c	fs: compat: Remove warning from COMPATIBLE_IOCTL	2018-04-08 11:51:57 +02:00
coredump.c	coredump: Ensure proper size of sparse core files	2017-07-05 14:37:20 +02:00
dax.c
dcache.c	Hang/soft lockup in d_invalidate with simultaneous calls	2019-04-03 06:23:19 +02:00
dcookies.c
direct-io.c	direct-io: Prevent NULL pointer access in submit_page_section	2017-10-18 09:20:42 +02:00
drop_caches.c	fs/drop_caches.c: avoid softlockups in drop_pagecache_sb()	2019-03-23 08:44:26 +01:00
eventfd.c
eventpoll.c	fs/epoll: drop ovflist branch prediction	2019-02-20 10:13:14 +01:00
exec.c	mm: replace get_user_pages() write/force parameters with gup_flags	2018-12-17 21:55:16 +01:00
fcntl.c	fs/fcntl: f_setown, avoid undefined behaviour	2018-01-31 12:06:11 +01:00
fhandle.c
file.c	fs/file.c: initialize init_files.resize_wait	2019-04-27 09:33:49 +02:00
file_table.c
filesystems.c
fs-writeback.c	bdi: Fix oops in wb_workfn()	2018-05-16 10:06:51 +02:00
fs_pin.c
fs_struct.c
inode.c	writeback: initialize inode members that track writeback history	2019-04-03 06:23:21 +02:00
internal.h
ioctl.c
Kconfig
Kconfig.binfmt
libfs.c
locks.c	locks: don't check for race with close when setting OFD lock	2018-01-17 09:35:27 +01:00
Makefile
mbcache.c
mount.h	mnt: In propgate_umount handle visiting mounts in any order	2017-07-21 07:44:57 +02:00
mpage.c	fs: add i_blocksize()	2017-06-14 13:16:24 +02:00
namei.c	namei: allow restricted O_CREAT of FIFOs and regular files	2018-12-01 09:46:41 +01:00
namespace.c	mount: Prevent MNT_DETACH from disconnecting locked mounts	2018-11-21 09:27:44 +01:00
no-block.c
nsfs.c	nsfs: mark dentry with DCACHE_RCUACCESS	2018-02-16 20:09:43 +01:00
open.c	fs: completely ignore unknown open flags	2017-07-15 11:57:44 +02:00
pipe.c	pipe: cap initial pipe capacity according to pipe-max-size limit	2018-05-26 08:48:51 +02:00
pnode.c	mnt: Make propagate_umount less slow for overlapping mount propagation trees	2017-07-21 07:44:58 +02:00
pnode.h	mnt: Add a per mount namespace limit on the number of mounts	2017-04-30 05:49:28 +02:00
posix_acl.c	tmpfs: clear S_ISGID when setting posix ACLs	2017-01-26 08:23:47 +01:00
proc_namespace.c
read_write.c	fs: add the fsnotify call to vfs_iter_write	2019-02-06 19:43:06 +01:00
readdir.c
select.c	fs/select: add vmalloc fallback for select(2)	2018-01-31 12:06:09 +01:00
seq_file.c	Make file credentials available to the seqfile interfaces	2017-08-06 19:19:42 -07:00
signalfd.c
splice.c	vfs: fix uninitialized flags in splice_to_pipe()	2017-02-23 17:43:09 +01:00
stack.c
stat.c	ufs: restore maintaining ->i_blocks	2017-06-14 13:16:24 +02:00
statfs.c
super.c	fs: don't scan the inode cache before SB_BORN is set	2019-02-06 19:43:08 +01:00
sync.c
timerfd.c	timerfd: Protect the might cancel mechanism proper	2017-05-08 07:46:01 +02:00
userfaultfd.c	userfaultfd: shmem: __do_fault requires VM_FAULT_NOPAGE	2017-12-20 10:04:53 +01:00
utimes.c
xattr.c	getxattr: use correct xattr length	2018-09-09 20:04:36 +02:00