From: Jan Kara Date: Tue, 9 Sep 2025 11:22:07 +0000 (+0200) Subject: ext4: verify orphan file size is not too big X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0a6ce20c156442a4ce2a404747bb0fb05d54eeb3;p=users%2Fhch%2Fmisc.git ext4: verify orphan file size is not too big 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 Message-ID: <20250909112206.10459-2-jack@suse.cz> Signed-off-by: Theodore Ts'o --- diff --git a/fs/ext4/orphan.c b/fs/ext4/orphan.c index 524d4658fa40..7e4f48c15c2e 100644 --- a/fs/ext4/orphan.c +++ b/fs/ext4/orphan.c @@ -587,9 +587,20 @@ int ext4_init_orphan_info(struct super_block *sb) 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) {