linux-toradex.git/fs/jfs/xattr.c, branch v7.2-rc5

jfs: fix slab-out-of-bounds read in ea_get()

2025-02-19T22:20:14+00:00

During the "size_check" label in ea_get(), the code checks if the extended
attribute list (xattr) size matches ea_size. If not, it logs
"ea_get: invalid extended attribute" and calls print_hex_dump().

Here, EALIST_SIZE(ea_buf->xattr) returns 4110417968, which exceeds
INT_MAX (2,147,483,647). Then ea_size is clamped:

	int size = clamp_t(int, ea_size, 0, EALIST_SIZE(ea_buf->xattr));

Although clamp_t aims to bound ea_size between 0 and 4110417968, the upper
limit is treated as an int, causing an overflow above 2^31 - 1. This leads
"size" to wrap around and become negative (-184549328).

The "size" is then passed to print_hex_dump() (called "len" in
print_hex_dump()), it is passed as type size_t (an unsigned
type), this is then stored inside a variable called
"int remaining", which is then assigned to "int linelen" which
is then passed to hex_dump_to_buffer(). In print_hex_dump()
the for loop, iterates through 0 to len-1, where len is
18446744073525002176, calling hex_dump_to_buffer()
on each iteration:

	for (i = 0; i < len; i += rowsize) {
		linelen = min(remaining, rowsize);
		remaining -= rowsize;

		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
				   linebuf, sizeof(linebuf), ascii);

		...
	}

The expected stopping condition (i < len) is effectively broken
since len is corrupted and very large. This eventually leads to
the "ptr+i" being passed to hex_dump_to_buffer() to get closer
to the end of the actual bounds of "ptr", eventually an out of
bounds access is done in hex_dump_to_buffer() in the following
for loop:

	for (j = 0; j < len; j++) {
			if (linebuflen < lx + 2)
				goto overflow2;
			ch = ptr[j];
		...
	}

To fix this we should validate "EALIST_SIZE(ea_buf->xattr)"
before it is utilised.

Reported-by: syzbot 
Tested-by: syzbot 
Closes: https://syzkaller.appspot.com/bug?extid=4e6e7e4279d046613bc5
Fixes: d9f9d96136cb ("jfs: xattr: check invalid xattr size more strictly")
Cc: stable@vger.kernel.org
Signed-off-by: Qasim Ijaz 
Signed-off-by: Dave Kleikamp

jfs: xattr: check invalid xattr size more strictly

2024-10-29T22:17:43+00:00

Commit 7c55b78818cf ("jfs: xattr: fix buffer overflow for invalid xattr")
also addresses this issue but it only fixes it for positive values, while
ea_size is an integer type and can take negative values, e.g. in case of
a corrupted filesystem. This still breaks validation and would overflow
because of implicit conversion from int to size_t in print_hex_dump().

Fix this issue by clamping the ea_size value instead.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Cc: stable@vger.kernel.org
Signed-off-by: Artem Sadovnikov 
Signed-off-by: Dave Kleikamp

jfs: Fix uninit-value access of new_ea in ea_buffer

2024-09-04T15:28:08+00:00

syzbot reports that lzo1x_1_do_compress is using uninit-value:

=====================================================
BUG: KMSAN: uninit-value in lzo1x_1_do_compress+0x19f9/0x2510 lib/lzo/lzo1x_compress.c:178

...

Uninit was stored to memory at:
 ea_put fs/jfs/xattr.c:639 [inline]

...

Local variable ea_buf created at:
 __jfs_setxattr+0x5d/0x1ae0 fs/jfs/xattr.c:662
 __jfs_xattr_set+0xe6/0x1f0 fs/jfs/xattr.c:934

=====================================================

The reason is ea_buf->new_ea is not initialized properly.

Fix this by using memset to empty its content at the beginning
in ea_get().

Reported-by: syzbot+02341e0daa42a15ce130@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=02341e0daa42a15ce130
Signed-off-by: Zhao Mengmeng 
Signed-off-by: Dave Kleikamp

Merge tag 'jfs-6.11' of github.com:kleikamp/linux-shaggy

2024-07-23T22:15:16+00:00

Pull jfs updates from David Kleikamp:
 "Folio conversion from Matthew Wilcox and a few various fixes"

* tag 'jfs-6.11' of github.com:kleikamp/linux-shaggy:
  jfs: don't walk off the end of ealist
  jfs: Fix shift-out-of-bounds in dbDiscardAG
  jfs: Fix array-index-out-of-bounds in diFree
  jfs: fix null ptr deref in dtInsertEntry
  jfs: Remove use of folio error flag
  fs: Remove i_blocks_per_page
  jfs: Change metapage->page to metapage->folio
  jfs: Convert force_metapage to use a folio
  jfs: Convert inc_io to take a folio
  jfs: Convert page_to_mp to folio_to_mp
  jfs; Convert __invalidate_metapages to use a folio
  jfs: Convert dec_io to take a folio
  jfs: Convert drop_metapage and remove_metapage to take a folio
  jfs; Convert release_metapage to use a folio
  jfs: Convert insert_metapage() to take a folio
  jfs: Convert __get_metapage to use a folio
  jfs: Convert metapage_writepage to metapage_write_folio
  jfs: Convert metapage_read_folio to use folio APIs

jfs: don't walk off the end of ealist

2024-06-27T13:43:07+00:00

Add a check before visiting the members of ea to
make sure each ea stays within the ealist.

Signed-off-by: lei lu 
Signed-off-by: Dave Kleikamp

jfs: xattr: fix buffer overflow for invalid xattr

2024-06-04T16:09:03+00:00

When an xattr size is not what is expected, it is printed out to the
kernel log in hex format as a form of debugging.  But when that xattr
size is bigger than the expected size, printing it out can cause an
access off the end of the buffer.

Fix this all up by properly restricting the size of the debug hex dump
in the kernel log.

Reported-by: syzbot+9dfe490c8176301c1d06@syzkaller.appspotmail.com
Cc: Dave Kleikamp 
Link: https://lore.kernel.org/r/2024051433-slider-cloning-98f9@gregkh
Signed-off-by: Greg Kroah-Hartman

jfs: move jfs_xattr_handlers to .rodata

2023-10-09T14:24:19+00:00

This makes it harder for accidental or malicious changes to
jfs_xattr_handlers at runtime.

Cc: Dave Kleikamp 
Cc: jfs-discussion@lists.sourceforge.net
Signed-off-by: Wedson Almeida Filho 
Link: https://lore.kernel.org/r/20230930050033.41174-17-wedsonaf@gmail.com
Reviewed-by: Dave Kleikamp 
Signed-off-by: Christian Brauner

jfs: convert to ctime accessor functions

2023-07-24T08:30:01+00:00

In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Acked-by: Dave Kleikamp 
Signed-off-by: Jeff Layton 
Reviewed-by: Jan Kara 
Message-Id: <20230705190309.579783-53-jlayton@kernel.org>
Signed-off-by: Christian Brauner

fs: drop unused posix acl handlers

2023-03-06T08:57:12+00:00

Remove struct posix_acl_{access,default}_handler for all filesystems
that don't depend on the xattr handler in their inode->i_op->listxattr()
method in any way. There's nothing more to do than to simply remove the
handler. It's been effectively unused ever since we introduced the new
posix acl api.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner (Microsoft)

fs: port xattr to mnt_idmap

2023-01-19T08:24:28+00:00

Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b42 ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Christian Brauner (Microsoft)