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authorFedor Pchelkin <pchelkin@ispras.ru>2023-01-17 13:52:26 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-01-31 16:44:08 -0800
commit72e544b1b28325fe78a4687b980871a7e4101f76 (patch)
tree9962f7fdd3d5c3ec02f968ce2103f085a97af802
parent6f28a2613497fc587e347afa99fa2c52230678a7 (diff)
squashfs: harden sanity check in squashfs_read_xattr_id_table
While mounting a corrupted filesystem, a signed integer '*xattr_ids' can become less than zero. This leads to the incorrect computation of 'len' and 'indexes' values which can cause null-ptr-deref in copy_bio_to_actor() or out-of-bounds accesses in the next sanity checks inside squashfs_read_xattr_id_table(). Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Link: https://lkml.kernel.org/r/20230117105226.329303-2-pchelkin@ispras.ru Fixes: 506220d2ba21 ("squashfs: add more sanity checks in xattr id lookup") Reported-by: <syzbot+082fa4af80a5bb1a9843@syzkaller.appspotmail.com> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru> Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru> Cc: Phillip Lougher <phillip@squashfs.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--fs/squashfs/xattr_id.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c
index 087cab8c78f4..f6d78cbc3e74 100644
--- a/fs/squashfs/xattr_id.c
+++ b/fs/squashfs/xattr_id.c
@@ -76,7 +76,7 @@ __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 table_start,
/* Sanity check values */
/* there is always at least one xattr id */
- if (*xattr_ids == 0)
+ if (*xattr_ids <= 0)
return ERR_PTR(-EINVAL);
len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);