From: Jan Kara jack@suse.cz
stable inclusion from stable-v5.10.224 commit 2199e157a465aaf98294d3932797ecd7fce942d5 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAKPZN CVE: CVE-2024-42306
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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 Signed-off-by: Ye Bin yebin10@huawei.com --- fs/udf/balloc.c | 15 +++++++++++++-- fs/udf/super.c | 3 ++- 2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/fs/udf/balloc.c b/fs/udf/balloc.c index f416b7fe092f..c4c18eeacb60 100644 --- a/fs/udf/balloc.c +++ b/fs/udf/balloc.c @@ -68,8 +68,12 @@ static int read_block_bitmap(struct super_block *sb, }
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 super_block *sb, 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) diff --git a/fs/udf/super.c b/fs/udf/super.c index 4af9ce34ee80..1939678f0b62 100644 --- a/fs/udf/super.c +++ b/fs/udf/super.c @@ -266,7 +266,8 @@ static void udf_sb_free_bitmap(struct udf_bitmap *bitmap) 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); }