This is a note to let you know that I've just added the patch titled
ext4: fix invalid free tracking in ext4_xattr_move_to_block()
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-invalid-free-tracking-in-ext4_xattr_move_to_block.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b87c7cdf2bed4928b899e1ce91ef0d147017ba45 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@xxxxxxx>
Date: Sun, 30 Apr 2023 03:04:13 -0400
Subject: ext4: fix invalid free tracking in ext4_xattr_move_to_block()
From: Theodore Ts'o <tytso@xxxxxxx>
commit b87c7cdf2bed4928b899e1ce91ef0d147017ba45 upstream.
In ext4_xattr_move_to_block(), the value of the extended attribute
which we need to move to an external block may be allocated by
kvmalloc() if the value is stored in an external inode. So at the end
of the function the code tried to check if this was the case by
testing entry->e_value_inum.
However, at this point, the pointer to the xattr entry is no longer
valid, because it was removed from the original location where it had
been stored. So we could end up calling kvfree() on a pointer which
was not allocated by kvmalloc(); or we could also potentially leak
memory by not freeing the buffer when it should be freed. Fix this by
storing whether it should be freed in a separate variable.
Cc: stable@xxxxxxxxxx
Link: https://lore.kernel.org/r/20230430160426.581366-1-tytso@xxxxxxx
Link: https://syzkaller.appspot.com/bug?id=5c2aee8256e30b55ccf57312c16d88417adbd5e1
Link: https://syzkaller.appspot.com/bug?id=41a6b5d4917c0412eb3b3c3c604965bed7d7420b
Reported-by: syzbot+64b645917ce07d89bde5@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: syzbot+0d042627c4f2ad332195@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/xattr.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2554,6 +2554,7 @@ static int ext4_xattr_move_to_block(hand
.in_inode = !!entry->e_value_inum,
};
struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode);
+ int needs_kvfree = 0;
int error;
is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS);
@@ -2576,7 +2577,7 @@ static int ext4_xattr_move_to_block(hand
error = -ENOMEM;
goto out;
}
-
+ needs_kvfree = 1;
error = ext4_xattr_inode_get(inode, entry, buffer, value_size);
if (error)
goto out;
@@ -2615,7 +2616,7 @@ static int ext4_xattr_move_to_block(hand
out:
kfree(b_entry_name);
- if (entry->e_value_inum && buffer)
+ if (needs_kvfree && buffer)
kvfree(buffer);
if (is)
brelse(is->iloc.bh);
Patches currently in stable-queue which might be from tytso@xxxxxxx are
queue-5.10/ext4-improve-error-recovery-code-paths-in-__ext4_remount.patch
queue-5.10/ext4-fix-use-after-free-read-in-ext4_find_extent-for.patch
queue-5.10/ext4-fix-warning-in-mb_find_extent.patch
queue-5.10/ext4-fix-deadlock-when-converting-an-inline-directory-in-nojournal-mode.patch
queue-5.10/ext4-bail-out-of-ext4_xattr_ibody_get-fails-for-any-reason.patch
queue-5.10/jdb2-don-t-refuse-invalidation-of-already-invalidate.patch
queue-5.10/ext4-add-bounds-checking-in-get_max_inline_xattr_value_size.patch
queue-5.10/ext4-avoid-a-potential-slab-out-of-bounds-in-ext4_group_desc_csum.patch
queue-5.10/ext4-check-iomap-type-only-if-ext4_iomap_begin-does-not-fail.patch
queue-5.10/ext4-fix-invalid-free-tracking-in-ext4_xattr_move_to_block.patch
queue-5.10/ext4-use-ext4_journal_start-stop-for-fast-commit-transactions.patch
queue-5.10/ext4-remove-a-bug_on-in-ext4_mb_release_group_pa.patch
queue-5.10/ext4-fix-data-races-when-using-cached-status-extents.patch
