5.15-stable review patch. If anyone has any objections, please let me know.
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From: Jan Kara jack@suse.cz
commit 0a6ce20c156442a4ce2a404747bb0fb05d54eeb3 upstream.
In principle orphan file can be arbitrarily large. However orphan replay needs to traverse it all and we also pin all its buffers in memory. Thus filesystems with absurdly large orphan files can lead to big amounts of memory consumed. Limit orphan file size to a sane value and also use kvmalloc() for allocating array of block descriptor structures to avoid large order allocations for sane but large orphan files.
Reported-by: syzbot+0b92850d68d9b12934f5@syzkaller.appspotmail.com Fixes: 02f310fcf47f ("ext4: Speedup ext4 orphan inode handling") Cc: stable@kernel.org Signed-off-by: Jan Kara jack@suse.cz Message-ID: 20250909112206.10459-2-jack@suse.cz Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/orphan.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
--- a/fs/ext4/orphan.c +++ b/fs/ext4/orphan.c @@ -584,9 +584,20 @@ int ext4_init_orphan_info(struct super_b ext4_msg(sb, KERN_ERR, "get orphan inode failed"); return PTR_ERR(inode); } + /* + * This is just an artificial limit to prevent corrupted fs from + * consuming absurd amounts of memory when pinning blocks of orphan + * file in memory. + */ + if (inode->i_size > 8 << 20) { + ext4_msg(sb, KERN_ERR, "orphan file too big: %llu", + (unsigned long long)inode->i_size); + ret = -EFSCORRUPTED; + goto out_put; + } oi->of_blocks = inode->i_size >> sb->s_blocksize_bits; oi->of_csum_seed = EXT4_I(inode)->i_csum_seed; - oi->of_binfo = kmalloc_array(oi->of_blocks, + oi->of_binfo = kvmalloc_array(oi->of_blocks, sizeof(struct ext4_orphan_block), GFP_KERNEL); if (!oi->of_binfo) {