5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jan Kara jack@suse.cz
commit a90d4471146de21745980cba51ce88e7926bcc4f upstream.
When the filesystem block bitmap is corrupted, we detect the corruption while loading the bitmap and fail the allocation with error. However the next allocation from the same bitmap will notice the bitmap buffer is already loaded and tries to allocate from the bitmap with mixed results (depending on the exact nature of the bitmap corruption). Fix the problem by using BH_verified bit to indicate whether the bitmap is valid or not.
Reported-by: syzbot+5f682cd029581f9edfd1@syzkaller.appspotmail.com CC: stable@vger.kernel.org Link: https://patch.msgid.link/20240617154201.29512-2-jack@suse.cz Fixes: 1e0d4adf17e7 ("udf: Check consistency of Space Bitmap Descriptor") Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/udf/balloc.c | 15 +++++++++++++-- fs/udf/super.c | 3 ++- 2 files changed, 15 insertions(+), 3 deletions(-)
--- a/fs/udf/balloc.c +++ b/fs/udf/balloc.c @@ -68,8 +68,12 @@ static int read_block_bitmap(struct supe }
for (i = 0; i < count; i++) - if (udf_test_bit(i + off, bh->b_data)) + if (udf_test_bit(i + off, bh->b_data)) { + bitmap->s_block_bitmap[bitmap_nr] = + ERR_PTR(-EFSCORRUPTED); + brelse(bh); return -EFSCORRUPTED; + } return 0; }
@@ -85,8 +89,15 @@ static int __load_block_bitmap(struct su block_group, nr_groups); }
- if (bitmap->s_block_bitmap[block_group]) + if (bitmap->s_block_bitmap[block_group]) { + /* + * The bitmap failed verification in the past. No point in + * trying again. + */ + if (IS_ERR(bitmap->s_block_bitmap[block_group])) + return PTR_ERR(bitmap->s_block_bitmap[block_group]); return block_group; + }
retval = read_block_bitmap(sb, bitmap, block_group, block_group); if (retval < 0) --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -266,7 +266,8 @@ static void udf_sb_free_bitmap(struct ud int nr_groups = bitmap->s_nr_groups;
for (i = 0; i < nr_groups; i++) - brelse(bitmap->s_block_bitmap[i]); + if (!IS_ERR_OR_NULL(bitmap->s_block_bitmap[i])) + brelse(bitmap->s_block_bitmap[i]);
kvfree(bitmap); }