From: Chao Yu <chao@xxxxxxxxxx> commit d3b7b4afd6b2c344eabf9cc26b8bfa903c164c7c upstream. syzbot found a f2fs bug: BUG: KASAN: slab-out-of-bounds in data_blkaddr fs/f2fs/f2fs.h:2891 [inline] BUG: KASAN: slab-out-of-bounds in is_alive fs/f2fs/gc.c:1117 [inline] BUG: KASAN: slab-out-of-bounds in gc_data_segment fs/f2fs/gc.c:1520 [inline] BUG: KASAN: slab-out-of-bounds in do_garbage_collect+0x386a/0x3df0 fs/f2fs/gc.c:1734 Read of size 4 at addr ffff888076557568 by task kworker/u4:3/52 CPU: 1 PID: 52 Comm: kworker/u4:3 Not tainted 6.1.0-rc4-syzkaller-00362-gfef7fd48922d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:284 [inline] print_report+0x15e/0x45d mm/kasan/report.c:395 kasan_report+0xbb/0x1f0 mm/kasan/report.c:495 data_blkaddr fs/f2fs/f2fs.h:2891 [inline] is_alive fs/f2fs/gc.c:1117 [inline] gc_data_segment fs/f2fs/gc.c:1520 [inline] do_garbage_collect+0x386a/0x3df0 fs/f2fs/gc.c:1734 f2fs_gc+0x88c/0x20a0 fs/f2fs/gc.c:1831 f2fs_balance_fs+0x544/0x6b0 fs/f2fs/segment.c:410 f2fs_write_inode+0x57e/0xe20 fs/f2fs/inode.c:753 write_inode fs/fs-writeback.c:1440 [inline] __writeback_single_inode+0xcfc/0x1440 fs/fs-writeback.c:1652 writeback_sb_inodes+0x54d/0xf90 fs/fs-writeback.c:1870 wb_writeback+0x2c5/0xd70 fs/fs-writeback.c:2044 wb_do_writeback fs/fs-writeback.c:2187 [inline] wb_workfn+0x2dc/0x12f0 fs/fs-writeback.c:2227 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 The root cause is that we forgot to do sanity check on .i_extra_isize in below path, result in accessing invalid address later, fix it. - gc_data_segment - is_alive - data_blkaddr - offset_in_addr Reported-by: syzbot+f8f3dfa4abc489e768a1@xxxxxxxxxxxxxxxxxxxxxxxxx Link: https://lore.kernel.org/linux-f2fs-devel/0000000000003cb3c405ed5c17f9@xxxxxxxxxx/T/#u Signed-off-by: Chao Yu <chao@xxxxxxxxxx> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/f2fs/gc.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -1078,7 +1078,7 @@ static bool is_alive(struct f2fs_sb_info { struct page *node_page; nid_t nid; - unsigned int ofs_in_node, max_addrs; + unsigned int ofs_in_node, max_addrs, base; block_t source_blkaddr; nid = le32_to_cpu(sum->nid); @@ -1104,11 +1104,17 @@ static bool is_alive(struct f2fs_sb_info return false; } - max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE : - DEF_ADDRS_PER_BLOCK; - if (ofs_in_node >= max_addrs) { - f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u", - ofs_in_node, dni->ino, dni->nid, max_addrs); + if (IS_INODE(node_page)) { + base = offset_in_addr(F2FS_INODE(node_page)); + max_addrs = DEF_ADDRS_PER_INODE; + } else { + base = 0; + max_addrs = DEF_ADDRS_PER_BLOCK; + } + + if (base + ofs_in_node >= max_addrs) { + f2fs_err(sbi, "Inconsistent blkaddr offset: base:%u, ofs_in_node:%u, max:%u, ino:%u, nid:%u", + base, ofs_in_node, max_addrs, dni->ino, dni->nid); f2fs_put_page(node_page, 1); return false; }
