[PATCH AUTOSEL 5.4 04/23] ext2: Add more validity checks for inode counts
STALE1522d
From: Sasha Levin <sashal@kernel.org>
Date: 2022-08-08 01:55:28
Also in:
lkml, stable
Subsystem:
ext2 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Jan Kara, Alexander Viro, Christian Brauner, Linus Torvalds
From: Jan Kara <jack@suse.cz> [ Upstream commit fa78f336937240d1bc598db817d638086060e7e9 ] Add checks verifying number of inodes stored in the superblock matches the number computed from number of inodes per group. Also verify we have at least one block worth of inodes per group. This prevents crashes on corrupted filesystems. Reported-by: syzbot+d273f7d7f58afd93be48@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/ext2/super.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index db403c01d4d5..644c83c115bc 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c@@ -1077,9 +1077,10 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) sbi->s_frags_per_group); goto failed_mount; } - if (sbi->s_inodes_per_group > sb->s_blocksize * 8) { + if (sbi->s_inodes_per_group < sbi->s_inodes_per_block || + sbi->s_inodes_per_group > sb->s_blocksize * 8) { ext2_msg(sb, KERN_ERR, - "error: #inodes per group too big: %lu", + "error: invalid #inodes per group: %lu", sbi->s_inodes_per_group); goto failed_mount; }
@@ -1089,6 +1090,13 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) - le32_to_cpu(es->s_first_data_block) - 1) / EXT2_BLOCKS_PER_GROUP(sb)) + 1; + if ((u64)sbi->s_groups_count * sbi->s_inodes_per_group != + le32_to_cpu(es->s_inodes_count)) { + ext2_msg(sb, KERN_ERR, "error: invalid #inodes: %u vs computed %llu", + le32_to_cpu(es->s_inodes_count), + (u64)sbi->s_groups_count * sbi->s_inodes_per_group); + goto failed_mount; + } db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) / EXT2_DESC_PER_BLOCK(sb); sbi->s_group_desc = kmalloc_array (db_count,
--
2.35.1