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Steven Rostedt (Google) ad57986463 tracefs: Check for dentry->d_inode exists in set_gid() 
If a getdents() is called on the tracefs directory but does not get all
the files, it can leave a "cursor" dentry in the d_subdirs list of tracefs
dentry. This cursor dentry does not have a d_inode for it. Before
referencing tracefs_inode from the dentry, the d_inode must first be
checked if it has content. If not, then it's not a tracefs_inode and can
be ignored.

The following caused a crash:

 #define getdents64(fd, dirp, count) syscall(SYS_getdents64, fd, dirp, count)
 #define BUF_SIZE 256
 #define TDIR "/tmp/file0"

 int main(void)
 {
	char buf[BUF_SIZE];
	int fd;
       	int n;

       	mkdir(TDIR, 0777);
	mount(NULL, TDIR, "tracefs", 0, NULL);
       	fd = openat(AT_FDCWD, TDIR, O_RDONLY);
       	n = getdents64(fd, buf, BUF_SIZE);
       	ret = mount(NULL, TDIR, NULL, MS_NOSUID|MS_REMOUNT|MS_RELATIME|MS_LAZYTIME,
		    "gid=1000");
	return 0;
 }

That's because the 256 BUF_SIZE was not big enough to read all the
dentries of the tracefs file system and it left a "cursor" dentry in the
subdirs of the tracefs root inode. Then on remounting with "gid=1000",
it would cause an iteration of all dentries which hit:

	ti = get_tracefs(dentry->d_inode);
	if (ti && (ti->flags & TRACEFS_EVENT_INODE))
		eventfs_update_gid(dentry, gid);

Which crashed because of the dereference of the cursor dentry which had a NULL
d_inode.

In the subdir loop of the dentry lookup of set_gid(), if a child has a
NULL d_inode, simply skip it.

Link: https://lore.kernel.org/all/20240102135637.3a21fb10@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20240102151249.05da244d@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 7e8358edf5 ("eventfs: Fix file and directory uid and gid ownership")
Reported-by: "Ubisectech Sirius" <bugreport@ubisectech.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-01-02 15:20:22 -05:00
..
9p Bunch of small fixes: 2023-11-04 09:20:04 -10:00
adfs adfs: convert to new timestamp accessors 2023-10-18 13:26:18 +02:00
affs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
afs asm-generic updates for v6.7 2023-11-01 15:28:33 -10:00
autofs vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
bcachefs bcachefs: Fix missing locking for dentry->d_parent access 2023-11-16 16:57:19 -05:00
befs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
bfs bfs: convert to new timestamp accessors 2023-10-18 13:26:19 +02:00
btrfs for-6.7-rc1-tag 2023-11-13 09:09:12 -08:00
cachefiles - Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list") 2023-08-29 14:25:26 -07:00
ceph Two items: 2023-11-10 09:52:56 -08:00
coda coda: convert to new timestamp accessors 2023-10-18 13:26:19 +02:00
configfs configfs: convert to new timestamp accessors 2023-10-18 13:26:19 +02:00
cramfs vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
crypto This update includes the following changes: 2023-11-02 16:15:30 -10:00
debugfs Driver core changes for 6.7-rc1 2023-11-03 15:15:47 -10:00
devpts devpts: convert to new timestamp accessors 2023-10-18 13:26:20 +02:00
dlm dlm: slow down filling up processing queue 2023-10-12 15:21:00 -05:00
ecryptfs ecryptfs: move ecryptfs_xattr_handlers to .rodata 2023-10-09 16:24:17 +02:00
efivarfs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
efs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
erofs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
exfat exfat: fix ctime is not updated 2023-11-03 22:24:11 +09:00
exportfs fs: fix build error with CONFIG_EXPORTFS=m or not defined 2023-10-28 16:16:19 +02:00
ext2 vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
ext4 vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
f2fs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
fat vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
freevxfs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
fscache
fuse vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
gfs2 gfs2 fixes 2023-11-07 11:54:17 -08:00
hfs vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
hfsplus vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
hostfs hostfs: convert to new timestamp accessors 2023-10-18 14:08:22 +02:00
hpfs hpfs: convert to new timestamp accessors 2023-10-18 14:08:22 +02:00
hugetlbfs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
iomap Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
isofs isofs: convert to new timestamp accessors 2023-10-18 14:08:22 +02:00
jbd2 Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
jffs2 vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
jfs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
kernfs Driver core changes for 6.7-rc1 2023-11-03 15:15:47 -10:00
lockd SUNRPC: change how svc threads are asked to exit. 2023-10-16 12:44:04 -04:00
minix minix: convert to new timestamp accessors 2023-10-18 14:08:23 +02:00
netfs netfs: Only call folio_start_fscache() one time for each folio 2023-09-18 12:03:46 -07:00
nfs NFS client updates for Linux 6.7 2023-11-08 13:39:16 -08:00
nfs_common
nfsd nfsd-6.7 fixes: 2023-11-18 11:23:32 -08:00
nilfs2 Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
nls nls: Hide new NLS_UCS2_UTILS 2023-08-31 12:07:34 -05:00
notify vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
ntfs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
ntfs3 vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
ocfs2 As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
omfs omfs: convert to new timestamp accessors 2023-10-18 14:08:25 +02:00
openpromfs openpromfs: convert to new timestamp accessors 2023-10-18 14:08:25 +02:00
orangefs vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
overlayfs ovl: fix memory leak in ovl_parse_param() 2023-11-14 08:09:36 +02:00
proc As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
pstore pstore updates for v6.7-rc1 2023-10-30 19:26:39 -10:00
qnx4 qnx4: convert to new timestamp accessors 2023-10-18 14:08:26 +02:00
qnx6 qnx6: convert to new timestamp accessors 2023-10-18 14:08:26 +02:00
quota Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
ramfs ramfs: convert to new timestamp accessors 2023-10-18 14:08:26 +02:00
reiserfs Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
romfs vfs-6.7.ctime 2023-10-30 09:47:13 -10:00
smb cifs: fix lock ordering while disabling multichannel 2023-11-14 11:39:35 -06:00
squashfs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
sysfs kernfs: sysfs: support custom llseek method for sysfs entries 2023-10-05 13:42:11 +02:00
sysv sysv: convert to new timestamp accessors 2023-10-18 14:08:28 +02:00
tracefs tracefs: Check for dentry->d_inode exists in set_gid() 2024-01-02 15:20:22 -05:00
ubifs This pull request contains updates for UBI and UBIFS 2023-11-05 08:28:32 -10:00
udf \n 2023-11-02 08:19:51 -10:00
ufs vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
unicode
vboxsf vboxsf: convert to new timestamp accessors 2023-10-18 14:08:29 +02:00
verity fsverity: skip PKCS#7 parser when keyring is empty 2023-08-20 10:33:43 -07:00
xfs xfs: recovery should not clear di_flushiter unconditionally 2023-11-13 09:11:41 +05:30
zonefs zonefs: convert to new timestamp accessors 2023-10-18 14:08:29 +02:00
aio.c aio: Annotate struct kioctx_table with __counted_by 2023-09-20 14:22:01 +02:00
anon_inodes.c treewide: mark stuff as __ro_after_init 2023-10-18 14:43:23 -07:00
attr.c fs: convert core infrastructure to new timestamp accessors 2023-10-18 13:26:15 +02:00
bad_inode.c fs: convert core infrastructure to new timestamp accessors 2023-10-18 13:26:15 +02:00
binfmt_elf_fdpic.c execve updates for v6.7-rc1 2023-10-30 19:28:19 -10:00
binfmt_elf_test.c
binfmt_elf.c binfmt_elf: Only report padzero() errors when PROT_WRITE 2023-10-03 19:48:44 -07:00
binfmt_flat.c
binfmt_misc.c execve updates for v6.7-rc1 2023-10-30 19:28:19 -10:00
binfmt_script.c
buffer.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
char_dev.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
compat_binfmt_elf.c
coredump.c v6.5/vfs.misc 2023-06-26 09:50:21 -07:00
d_path.c
dax.c mm: convert DAX lock/unlock page to lock/unlock folio 2023-10-04 10:32:20 -07:00
dcache.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
direct-io.c treewide: mark stuff as __ro_after_init 2023-10-18 14:43:23 -07:00
drop_caches.c fs: drop_caches: draining pages before dropping caches 2023-08-18 10:12:11 -07:00
eventfd.c eventfd: prevent underflow for eventfd semaphores 2023-07-11 11:41:34 +02:00
eventpoll.c treewide: mark stuff as __ro_after_init 2023-10-18 14:43:23 -07:00
exec.c mm/mremap: allow moves within the same VMA for stack moves 2023-10-04 10:32:20 -07:00
fcntl.c treewide: mark stuff as __ro_after_init 2023-10-18 14:43:23 -07:00
fhandle.c exportfs: add helpers to check if filesystem can encode/decode file handles 2023-10-24 17:57:45 +02:00
file_table.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
file.c file, i915: fix file reference for mmap_singleton() 2023-10-25 22:17:04 +02:00
filesystems.c
fs_context.c fs: factor out vfs_parse_monolithic_sep() helper 2023-10-12 18:53:36 +03:00
fs_parser.c
fs_pin.c
fs_struct.c kill do_each_thread() 2023-08-21 13:46:25 -07:00
fs_types.c
fs-writeback.c vfs-6.7.misc 2023-10-30 09:14:19 -10:00
fsopen.c fsconfig: ensure that dirfd is set to aux 2023-09-22 14:09:06 +02:00
init.c fs: add a new SB_I_NOUMASK flag 2023-10-19 11:02:47 +02:00
inode.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
internal.h fs: store real path instead of fake path in backing file f_path 2023-10-19 11:03:15 +02:00
ioctl.c v6.6-vfs.super 2023-08-28 11:04:18 -07:00
Kconfig asm-generic updates for v6.7 2023-11-01 15:28:33 -10:00
Kconfig.binfmt riscv: support the elf-fdpic binfmt loader 2023-08-23 14:17:43 -07:00
kernel_read_file.c fs: Fix kernel-doc warnings 2023-08-19 12:12:12 +02:00
libfs.c vfs-6.7.fsid 2023-11-07 12:11:26 -08:00
locks.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
Makefile bcachefs: Initial commit 2023-10-22 17:08:07 -04:00
mbcache.c mbcache: dynamically allocate the mbcache shrinker 2023-10-04 10:32:25 -07:00
mnt_idmapping.c fs: export mnt_idmap_get/mnt_idmap_put 2023-11-03 23:28:33 +01:00
mount.h
mpage.c buffer: remove folio_create_empty_buffers() 2023-10-25 16:47:10 -07:00
namei.c vfs-6.7.misc 2023-10-30 09:14:19 -10:00
namespace.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
nsfs.c fs: convert core infrastructure to new timestamp accessors 2023-10-18 13:26:15 +02:00
open.c fs: store real path instead of fake path in backing file f_path 2023-10-19 11:03:15 +02:00
pipe.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
pnode.c
pnode.h
posix_acl.c fs: convert to ctime accessor functions 2023-07-13 10:28:04 +02:00
proc_namespace.c
read_write.c fs: Fix one kernel-doc comment 2023-08-15 08:32:45 +02:00
readdir.c vfs: get rid of old '->iterate' directory operation 2023-08-06 15:08:35 +02:00
remap_range.c
select.c
seq_file.c
signalfd.c
splice.c - Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list") 2023-08-29 14:25:26 -07:00
stack.c fs: convert core infrastructure to new timestamp accessors 2023-10-18 13:26:15 +02:00
stat.c fs: convert core infrastructure to new timestamp accessors 2023-10-18 13:26:15 +02:00
statfs.c
super.c overlayfs update for 6.7-rc1 2023-11-07 11:46:31 -08:00
sync.c
sysctls.c
timerfd.c
userfaultfd.c As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
utimes.c
xattr.c xattr: make the xattr array itself const 2023-10-09 16:24:16 +02:00