[PATCH v2 2/2] f2fs: fix to do sanity check with extra_attr feature
From: Chao Yu If FI_EXTRA_ATTR is set in inode by fuzzing, inode.i_addr[0] will be parsed as inode.i_extra_isize, then in __recover_inline_status, inline data address will beyond boundary of page, result in accessing invalid memory. So in this condition, during reading inode page, let's do sanity check with EXTRA_ATTR feature of fs and extra_attr bit of inode, if they're inconsistent, deny to load this inode. - Overview Out-of-bound access in f2fs_iget() when mounting a corrupted f2fs image - Reproduce The following message will be got in KASAN build of 4.18 upstream kernel. [ 819.392227] == [ 819.393901] BUG: KASAN: slab-out-of-bounds in f2fs_iget+0x736/0x1530 [ 819.395329] Read of size 4 at addr 8801f099c968 by task mount/1292 [ 819.397079] CPU: 1 PID: 1292 Comm: mount Not tainted 4.18.0-rc1+ #4 [ 819.397082] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 819.397088] Call Trace: [ 819.397124] dump_stack+0x7b/0xb5 [ 819.397154] print_address_description+0x70/0x290 [ 819.397159] kasan_report+0x291/0x390 [ 819.397163] ? f2fs_iget+0x736/0x1530 [ 819.397176] check_memory_region+0x139/0x190 [ 819.397182] __asan_loadN+0xf/0x20 [ 819.397185] f2fs_iget+0x736/0x1530 [ 819.397197] f2fs_fill_super+0x1b4f/0x2b40 [ 819.397202] ? f2fs_fill_super+0x1b4f/0x2b40 [ 819.397208] ? f2fs_commit_super+0x1b0/0x1b0 [ 819.397227] ? set_blocksize+0x90/0x140 [ 819.397241] mount_bdev+0x1c5/0x210 [ 819.397245] ? f2fs_commit_super+0x1b0/0x1b0 [ 819.397252] f2fs_mount+0x15/0x20 [ 819.397256] mount_fs+0x60/0x1a0 [ 819.397267] ? alloc_vfsmnt+0x309/0x360 [ 819.397272] vfs_kern_mount+0x6b/0x1a0 [ 819.397282] do_mount+0x34a/0x18c0 [ 819.397300] ? lockref_put_or_lock+0xcf/0x160 [ 819.397306] ? copy_mount_string+0x20/0x20 [ 819.397318] ? memcg_kmem_put_cache+0x1b/0xa0 [ 819.397324] ? kasan_check_write+0x14/0x20 [ 819.397334] ? _copy_from_user+0x6a/0x90 [ 819.397353] ? memdup_user+0x42/0x60 [ 819.397359] ksys_mount+0x83/0xd0 [ 819.397365] __x64_sys_mount+0x67/0x80 [ 819.397388] do_syscall_64+0x78/0x170 [ 819.397403] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 819.397422] RIP: 0033:0x7f54c667cb9a [ 819.397424] Code: 48 8b 0d 01 c3 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ce c2 2b 00 f7 d8 64 89 01 48 [ 819.397483] RSP: 002b:7ffd8f46cd08 EFLAGS: 0202 ORIG_RAX: 00a5 [ 819.397496] RAX: ffda RBX: 00dfa030 RCX: 7f54c667cb9a [ 819.397498] RDX: 00dfa210 RSI: 00dfbf30 RDI: 00e02ec0 [ 819.397501] RBP: R08: R09: 0013 [ 819.397503] R10: c0ed R11: 0202 R12: 00e02ec0 [ 819.397505] R13: 00dfa210 R14: R15: 0003 [ 819.397866] Allocated by task 139: [ 819.398702] save_stack+0x46/0xd0 [ 819.398705] kasan_kmalloc+0xad/0xe0 [ 819.398709] kasan_slab_alloc+0x11/0x20 [ 819.398713] kmem_cache_alloc+0xd1/0x1e0 [ 819.398717] dup_fd+0x50/0x4c0 [ 819.398740] copy_process.part.37+0xbed/0x32e0 [ 819.398744] _do_fork+0x16e/0x590 [ 819.398748] __x64_sys_clone+0x69/0x80 [ 819.398752] do_syscall_64+0x78/0x170 [ 819.398756] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 819.399097] Freed by task 159: [ 819.399743] save_stack+0x46/0xd0 [ 819.399747] __kasan_slab_free+0x13c/0x1a0 [ 819.399750] kasan_slab_free+0xe/0x10 [ 819.399754] kmem_cache_free+0x89/0x1e0 [ 819.399757] put_files_struct+0x132/0x150 [ 819.399761] exit_files+0x62/0x70 [ 819.399766] do_exit+0x47b/0x1390 [ 819.399770] do_group_exit+0x86/0x130 [ 819.399774] __x64_sys_exit_group+0x2c/0x30 [ 819.399778] do_syscall_64+0x78/0x170 [ 819.399782] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 819.400115] The buggy address belongs to the object at 8801f099c680 which belongs to the cache files_cache of size 704 [ 819.403234] The buggy address is located 40 bytes to the right of 704-byte region [8801f099c680, 8801f099c940) [ 819.405689] The buggy address belongs to the page: [ 819.406709] page:ea0007c26700 count:1 mapcount:0 mapping:8801f69a3340 index:0x8801f099d380 compound_mapcount: 0 [ 819.408984] flags: 0x2008100(slab|head) [ 819.409932] raw: 02008100 ea00077fb600 00020002 8801f69a3340 [ 819.411514] raw: 8801f099d380 8013 0001 [ 819.413073] page dumped because: kasan: bad access detected [ 819.414539] Memory state around the buggy address: [ 819.415521] 8801f099c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 819.416981] 8801f099c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 819.418454] >8801f099c900: fb fb fb fb fb fb fb fb fc
[PATCH v2 2/2] f2fs: fix to do sanity check with extra_attr feature
From: Chao Yu If FI_EXTRA_ATTR is set in inode by fuzzing, inode.i_addr[0] will be parsed as inode.i_extra_isize, then in __recover_inline_status, inline data address will beyond boundary of page, result in accessing invalid memory. So in this condition, during reading inode page, let's do sanity check with EXTRA_ATTR feature of fs and extra_attr bit of inode, if they're inconsistent, deny to load this inode. - Overview Out-of-bound access in f2fs_iget() when mounting a corrupted f2fs image - Reproduce The following message will be got in KASAN build of 4.18 upstream kernel. [ 819.392227] == [ 819.393901] BUG: KASAN: slab-out-of-bounds in f2fs_iget+0x736/0x1530 [ 819.395329] Read of size 4 at addr 8801f099c968 by task mount/1292 [ 819.397079] CPU: 1 PID: 1292 Comm: mount Not tainted 4.18.0-rc1+ #4 [ 819.397082] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 [ 819.397088] Call Trace: [ 819.397124] dump_stack+0x7b/0xb5 [ 819.397154] print_address_description+0x70/0x290 [ 819.397159] kasan_report+0x291/0x390 [ 819.397163] ? f2fs_iget+0x736/0x1530 [ 819.397176] check_memory_region+0x139/0x190 [ 819.397182] __asan_loadN+0xf/0x20 [ 819.397185] f2fs_iget+0x736/0x1530 [ 819.397197] f2fs_fill_super+0x1b4f/0x2b40 [ 819.397202] ? f2fs_fill_super+0x1b4f/0x2b40 [ 819.397208] ? f2fs_commit_super+0x1b0/0x1b0 [ 819.397227] ? set_blocksize+0x90/0x140 [ 819.397241] mount_bdev+0x1c5/0x210 [ 819.397245] ? f2fs_commit_super+0x1b0/0x1b0 [ 819.397252] f2fs_mount+0x15/0x20 [ 819.397256] mount_fs+0x60/0x1a0 [ 819.397267] ? alloc_vfsmnt+0x309/0x360 [ 819.397272] vfs_kern_mount+0x6b/0x1a0 [ 819.397282] do_mount+0x34a/0x18c0 [ 819.397300] ? lockref_put_or_lock+0xcf/0x160 [ 819.397306] ? copy_mount_string+0x20/0x20 [ 819.397318] ? memcg_kmem_put_cache+0x1b/0xa0 [ 819.397324] ? kasan_check_write+0x14/0x20 [ 819.397334] ? _copy_from_user+0x6a/0x90 [ 819.397353] ? memdup_user+0x42/0x60 [ 819.397359] ksys_mount+0x83/0xd0 [ 819.397365] __x64_sys_mount+0x67/0x80 [ 819.397388] do_syscall_64+0x78/0x170 [ 819.397403] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 819.397422] RIP: 0033:0x7f54c667cb9a [ 819.397424] Code: 48 8b 0d 01 c3 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ce c2 2b 00 f7 d8 64 89 01 48 [ 819.397483] RSP: 002b:7ffd8f46cd08 EFLAGS: 0202 ORIG_RAX: 00a5 [ 819.397496] RAX: ffda RBX: 00dfa030 RCX: 7f54c667cb9a [ 819.397498] RDX: 00dfa210 RSI: 00dfbf30 RDI: 00e02ec0 [ 819.397501] RBP: R08: R09: 0013 [ 819.397503] R10: c0ed R11: 0202 R12: 00e02ec0 [ 819.397505] R13: 00dfa210 R14: R15: 0003 [ 819.397866] Allocated by task 139: [ 819.398702] save_stack+0x46/0xd0 [ 819.398705] kasan_kmalloc+0xad/0xe0 [ 819.398709] kasan_slab_alloc+0x11/0x20 [ 819.398713] kmem_cache_alloc+0xd1/0x1e0 [ 819.398717] dup_fd+0x50/0x4c0 [ 819.398740] copy_process.part.37+0xbed/0x32e0 [ 819.398744] _do_fork+0x16e/0x590 [ 819.398748] __x64_sys_clone+0x69/0x80 [ 819.398752] do_syscall_64+0x78/0x170 [ 819.398756] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 819.399097] Freed by task 159: [ 819.399743] save_stack+0x46/0xd0 [ 819.399747] __kasan_slab_free+0x13c/0x1a0 [ 819.399750] kasan_slab_free+0xe/0x10 [ 819.399754] kmem_cache_free+0x89/0x1e0 [ 819.399757] put_files_struct+0x132/0x150 [ 819.399761] exit_files+0x62/0x70 [ 819.399766] do_exit+0x47b/0x1390 [ 819.399770] do_group_exit+0x86/0x130 [ 819.399774] __x64_sys_exit_group+0x2c/0x30 [ 819.399778] do_syscall_64+0x78/0x170 [ 819.399782] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 819.400115] The buggy address belongs to the object at 8801f099c680 which belongs to the cache files_cache of size 704 [ 819.403234] The buggy address is located 40 bytes to the right of 704-byte region [8801f099c680, 8801f099c940) [ 819.405689] The buggy address belongs to the page: [ 819.406709] page:ea0007c26700 count:1 mapcount:0 mapping:8801f69a3340 index:0x8801f099d380 compound_mapcount: 0 [ 819.408984] flags: 0x2008100(slab|head) [ 819.409932] raw: 02008100 ea00077fb600 00020002 8801f69a3340 [ 819.411514] raw: 8801f099d380 8013 0001 [ 819.413073] page dumped because: kasan: bad access detected [ 819.414539] Memory state around the buggy address: [ 819.415521] 8801f099c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 819.416981] 8801f099c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 819.418454] >8801f099c900: fb fb fb fb fb fb fb fb fc
