From: Jan Kara jack@suse.cz
[ Upstream commit e7c7fbb9a8574ebd89cc05db49d806c7476863ad ]
Array of group descriptor block buffers can get rather large. In theory in can reach 1MB for perfectly valid filesystem and even more for maliciously crafted ones. Use kvmalloc() to allocate the array to avoid straining memory allocator with large order allocations unnecessarily.
Reported-by: syzbot+0f2f7e65a3007d39539f@syzkaller.appspotmail.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- fs/ext2/super.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 252c742379cf..98348357a356 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -163,7 +163,7 @@ static void ext2_put_super (struct super_block * sb) db_count = sbi->s_gdb_count; for (i = 0; i < db_count; i++) brelse(sbi->s_group_desc[i]); - kfree(sbi->s_group_desc); + kvfree(sbi->s_group_desc); kfree(sbi->s_debts); percpu_counter_destroy(&sbi->s_freeblocks_counter); percpu_counter_destroy(&sbi->s_freeinodes_counter); @@ -1080,7 +1080,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) } 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, + sbi->s_group_desc = kvmalloc_array(db_count, sizeof(struct buffer_head *), GFP_KERNEL); if (sbi->s_group_desc == NULL) { @@ -1206,7 +1206,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) for (i = 0; i < db_count; i++) brelse(sbi->s_group_desc[i]); failed_mount_group_desc: - kfree(sbi->s_group_desc); + kvfree(sbi->s_group_desc); kfree(sbi->s_debts); failed_mount: brelse(bh);