| Message ID | 445fecb5586ce0bbe3f1a42417858d1b3df6819b.1731670907.git.fdmanana@suse.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | btrfs: ref-verify: fix use-after-free after invalid ref action | expand |
On Fri, Nov 15, 2024 at 11:43 AM <fdmanana@kernel.org> wrote: > > From: Filipe Manana <fdmanana@suse.com> > > At btrfs_ref_tree_mod() after we successfully inserted the new ref entry > (local variable 'ref') into the respective block entry's rbtree (local > variable 'be'), if we find an unexpected action of BTRFS_DROP_DELAYED_REF, > we error out and free the ref entry without removing it from the block > entry's rbtree. Then in the error path of btrfs_ref_tree_mod() we call > btrfs_free_ref_cache(), which iterates over all block entries and then > calls free_block_entry() for each one, and there we will trigger a > use-after-free when we are called against the block entry to which we > added the freed ref entry to its rbtree, since the rbtree still points > to the block entry, as we didn't remove it from the rbtree before freeing > it in the error path at btrfs_ref_tree_mod(). Fix this by removing the > new ref entry from the rbtree before freeing it. > > Syzbot report this with the following stack traces: > > BTRFS error (device loop0 state EA): Ref action 2, root 5, ref_root 0, parent 8564736, owner 0, offset 0, num_refs 18446744073709551615 > __btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523 > update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512 > btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594 > btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754 > btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116 > btrfs_insert_empty_items+0x9c/0x1a0 fs/btrfs/ctree.c:4314 > btrfs_insert_empty_item fs/btrfs/ctree.h:669 [inline] > btrfs_insert_orphan_item+0x1f1/0x320 fs/btrfs/orphan.c:23 > btrfs_orphan_add+0x6d/0x1a0 fs/btrfs/inode.c:3482 > btrfs_unlink+0x267/0x350 fs/btrfs/inode.c:4293 > vfs_unlink+0x365/0x650 fs/namei.c:4469 > do_unlinkat+0x4ae/0x830 fs/namei.c:4533 > __do_sys_unlinkat fs/namei.c:4576 [inline] > __se_sys_unlinkat fs/namei.c:4569 [inline] > __x64_sys_unlinkat+0xcc/0xf0 fs/namei.c:4569 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > BTRFS error (device loop0 state EA): Ref action 1, root 5, ref_root 5, parent 0, owner 260, offset 0, num_refs 1 > __btrfs_mod_ref+0x76b/0xac0 fs/btrfs/extent-tree.c:2521 > update_ref_for_cow+0x96a/0x11f0 > btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594 > btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754 > btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116 > btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411 > __btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030 > btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline] > __btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137 > __btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171 > btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313 > prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586 > relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611 > btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081 > btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377 > __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161 > btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538 > BTRFS error (device loop0 state EA): Ref action 2, root 5, ref_root 0, parent 8564736, owner 0, offset 0, num_refs 18446744073709551615 > __btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523 > update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512 > btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594 > btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754 > btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116 > btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411 > __btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030 > btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline] > __btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137 > __btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171 > btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313 > prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586 > relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611 > btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081 > btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377 > __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161 > btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538 > ================================================================== > BUG: KASAN: slab-use-after-free in rb_first+0x69/0x70 lib/rbtree.c:473 > Read of size 8 at addr ffff888042d1af38 by task syz.0.0/5329 > > CPU: 0 UID: 0 PID: 5329 Comm: syz.0.0 Not tainted 6.12.0-rc7-syzkaller #0 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 > Call Trace: > <TASK> > __dump_stack lib/dump_stack.c:94 [inline] > dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 > print_address_description mm/kasan/report.c:377 [inline] > print_report+0x169/0x550 mm/kasan/report.c:488 > kasan_report+0x143/0x180 mm/kasan/report.c:601 > rb_first+0x69/0x70 lib/rbtree.c:473 > free_block_entry+0x78/0x230 fs/btrfs/ref-verify.c:248 > btrfs_free_ref_cache+0xa3/0x100 fs/btrfs/ref-verify.c:917 > btrfs_ref_tree_mod+0x139f/0x15e0 fs/btrfs/ref-verify.c:898 > btrfs_free_extent+0x33c/0x380 fs/btrfs/extent-tree.c:3544 > __btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523 > update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512 > btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594 > btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754 > btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116 > btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411 > __btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030 > btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline] > __btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137 > __btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171 > btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313 > prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586 > relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611 > btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081 > btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377 > __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161 > btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538 > btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f996df7e719 > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007f996ede7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f996e135f80 RCX: 00007f996df7e719 > RDX: 0000000020000180 RSI: 00000000c4009420 RDI: 0000000000000004 > RBP: 00007f996dff139e R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 > R13: 0000000000000000 R14: 00007f996e135f80 R15: 00007fff79f32e68 > </TASK> > > Allocated by task 5329: > kasan_save_stack mm/kasan/common.c:47 [inline] > kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 > poison_kmalloc_redzone mm/kasan/common.c:377 [inline] > __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394 > kasan_kmalloc include/linux/kasan.h:257 [inline] > __kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4295 > kmalloc_noprof include/linux/slab.h:878 [inline] > kzalloc_noprof include/linux/slab.h:1014 [inline] > btrfs_ref_tree_mod+0x264/0x15e0 fs/btrfs/ref-verify.c:701 > btrfs_free_extent+0x33c/0x380 fs/btrfs/extent-tree.c:3544 > __btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523 > update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512 > btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594 > btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754 > btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116 > btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411 > __btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030 > btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline] > __btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137 > __btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171 > btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313 > prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586 > relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611 > btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081 > btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377 > __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161 > btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538 > btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Freed by task 5329: > kasan_save_stack mm/kasan/common.c:47 [inline] > kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 > kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579 > poison_slab_object mm/kasan/common.c:247 [inline] > __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264 > kasan_slab_free include/linux/kasan.h:230 [inline] > slab_free_hook mm/slub.c:2342 [inline] > slab_free mm/slub.c:4579 [inline] > kfree+0x1a0/0x440 mm/slub.c:4727 > btrfs_ref_tree_mod+0x136c/0x15e0 > btrfs_free_extent+0x33c/0x380 fs/btrfs/extent-tree.c:3544 > __btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523 > update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512 > btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594 > btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754 > btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116 > btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411 > __btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030 > btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline] > __btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137 > __btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171 > btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313 > prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586 > relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611 > btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081 > btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377 > __btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161 > btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538 > btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > The buggy address belongs to the object at ffff888042d1af00 > which belongs to the cache kmalloc-64 of size 64 > The buggy address is located 56 bytes inside of > freed 64-byte region [ffff888042d1af00, ffff888042d1af40) > > The buggy address belongs to the physical page: > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x42d1a > anon flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff) > page_type: f5(slab) > raw: 04fff00000000000 ffff88801ac418c0 0000000000000000 dead000000000001 > raw: 0000000000000000 0000000000200020 00000001f5000000 0000000000000000 > page dumped because: kasan: bad access detected > page_owner tracks the page as allocated > page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5055, tgid 5055 (dhcpcd-run-hook), ts 40377240074, free_ts 40376848335 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1541 > prep_new_page mm/page_alloc.c:1549 [inline] > get_page_from_freelist+0x3649/0x3790 mm/page_alloc.c:3459 > __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4735 > alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265 > alloc_slab_page+0x6a/0x140 mm/slub.c:2412 > allocate_slab+0x5a/0x2f0 mm/slub.c:2578 > new_slab mm/slub.c:2631 [inline] > ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3818 > __slab_alloc+0x58/0xa0 mm/slub.c:3908 > __slab_alloc_node mm/slub.c:3961 [inline] > slab_alloc_node mm/slub.c:4122 [inline] > __do_kmalloc_node mm/slub.c:4263 [inline] > __kmalloc_noprof+0x25a/0x400 mm/slub.c:4276 > kmalloc_noprof include/linux/slab.h:882 [inline] > kzalloc_noprof include/linux/slab.h:1014 [inline] > tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] > tomoyo_encode+0x26f/0x540 security/tomoyo/realpath.c:80 > tomoyo_realpath_from_path+0x59e/0x5e0 security/tomoyo/realpath.c:283 > tomoyo_get_realpath security/tomoyo/file.c:151 [inline] > tomoyo_check_open_permission+0x255/0x500 security/tomoyo/file.c:771 > security_file_open+0x777/0x990 security/security.c:3109 > do_dentry_open+0x369/0x1460 fs/open.c:945 > vfs_open+0x3e/0x330 fs/open.c:1088 > do_open fs/namei.c:3774 [inline] > path_openat+0x2c84/0x3590 fs/namei.c:3933 > page last free pid 5055 tgid 5055 stack trace: > reset_page_owner include/linux/page_owner.h:25 [inline] > free_pages_prepare mm/page_alloc.c:1112 [inline] > free_unref_page+0xcfb/0xf20 mm/page_alloc.c:2642 > free_pipe_info+0x300/0x390 fs/pipe.c:860 > put_pipe_info fs/pipe.c:719 [inline] > pipe_release+0x245/0x320 fs/pipe.c:742 > __fput+0x23f/0x880 fs/file_table.c:431 > __do_sys_close fs/open.c:1567 [inline] > __se_sys_close fs/open.c:1552 [inline] > __x64_sys_close+0x7f/0x110 fs/open.c:1552 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Memory state around the buggy address: > ffff888042d1ae00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff888042d1ae80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc > >ffff888042d1af00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ^ > ffff888042d1af80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc > ffff888042d1b000: 00 00 00 00 00 fc fc 00 00 00 00 00 fc fc 00 00 > ================================================================== > > Reported-by: syzbot+7325f164162e200000c1@syzkaller.appspotmail.com Missing: Link: https://lore.kernel.org/linux-btrfs/673723eb.050a0220.1324f8.00a8.GAE@google.com/T/#u Will add when committing to the for-next branch. > Fixes: fd708b81d972 ("Btrfs: add a extent ref verify tool") > Signed-off-by: Filipe Manana <fdmanana@suse.com> > --- > fs/btrfs/ref-verify.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c > index 9522a8b79d22..2928abf7eb82 100644 > --- a/fs/btrfs/ref-verify.c > +++ b/fs/btrfs/ref-verify.c > @@ -857,6 +857,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info, > "dropping a ref for a root that doesn't have a ref on the block"); > dump_block_entry(fs_info, be); > dump_ref_action(fs_info, ra); > + rb_erase(&ref->node, &be->refs); > kfree(ref); > kfree(ra); > goto out_unlock; > -- > 2.45.2 > >
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c index 9522a8b79d22..2928abf7eb82 100644 --- a/fs/btrfs/ref-verify.c +++ b/fs/btrfs/ref-verify.c @@ -857,6 +857,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info, "dropping a ref for a root that doesn't have a ref on the block"); dump_block_entry(fs_info, be); dump_ref_action(fs_info, ra); + rb_erase(&ref->node, &be->refs); kfree(ref); kfree(ra); goto out_unlock;