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KASAN: out-of-bounds Read in ext4_xattr_set_entry

Status: upstream: reported C repro on 2023/09/20 02:40
Reported-by: syzbot+9b8029e222e845c4480b@syzkaller.appspotmail.com
First crash: 221d, last: 11d
▶ ▼ Similar bugs (13)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Read in ext4_xattr_set_entry (2) C done 7 958d 1416d 1/1 fixed on 2021/10/13 07:23
android-5-15 KASAN: out-of-bounds Read in ext4_xattr_set_entry 1 313d 313d 0/2 auto-obsoleted due to no activity on 2023/09/17 07:02
android-54 KASAN: out-of-bounds Read in ext4_xattr_set_entry ext4 C 14 367d 1133d 0/2 auto-obsoleted due to no activity on 2023/08/23 09:06
linux-6.1 KASAN: out-of-bounds Read in ext4_xattr_set_entry origin:upstream missing-backport syz unreliable 1 313d 344d 0/3 upstream: reported syz repro on 2023/05/19 08:42
linux-4.14 KASAN: out-of-bounds Read in ext4_xattr_set_entry C error 2 597d 1111d 0/1 upstream: reported C repro on 2021/04/12 14:20
android-5-15 general protection fault in ext4_xattr_set_entry C error 1 422d 502d 2/2 fixed on 2023/03/28 12:29
android-5-10 general protection fault in ext4_xattr_set_entry (4) C error 62 325d 354d 2/2 fixed on 2023/06/07 17:22
android-5-10 general protection fault in ext4_xattr_set_entry (2) ext4 C error 423 360d 560d 2/2 fixed on 2023/05/03 13:06
upstream KASAN: use-after-free Read in ext4_xattr_set_entry (5) ext4 2 642d 700d 0/26 auto-obsoleted due to no activity on 2022/11/22 17:19
android-5-10 general protection fault in ext4_xattr_set_entry (3) C error 9 356d 359d 2/2 fixed on 2023/05/08 19:06
upstream KASAN: use-after-free Read in ext4_xattr_set_entry (4) ext4 C error done 21 796d 1183d 20/26 fixed on 2022/03/28 10:17
android-5-10 general protection fault in ext4_xattr_set_entry C error 2 583d 597d 0/2 closed as invalid on 2022/09/26 18:30
android-5-10 general protection fault in ext4_xattr_set_entry (5) C done 11 322d 324d 2/2 fixed on 2023/06/13 02:27
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2023/10/04 02:45 8m retest repro android13-5.10-lts report log
▶ ▼ Fix bisection attempts (6)
Created Duration User Patch Repo Result
2024/04/16 22:07 1h18m bisect fix android13-5.10-lts job log (0) log
2024/03/14 11:41 1h47m bisect fix android13-5.10-lts job log (0) log
2024/02/11 02:19 1h09m bisect fix android13-5.10-lts job log (0) log
2024/01/05 01:17 1h12m bisect fix android13-5.10-lts job log (0) log
2023/12/05 19:48 1h18m bisect fix android13-5.10-lts job log (0) log
2023/11/04 13:28 1h06m bisect fix android13-5.10-lts job log (0) log

Sample crash report:
==================================================================
BUG: KASAN: out-of-bounds in ext4_xattr_set_entry+0x1277/0x3a90 fs/ext4/xattr.c:1747
Read of size 18446744073709551552 at addr ffff88811c3252e8 by task syz-executor567/16160

CPU: 0 PID: 16160 Comm: syz-executor567 Not tainted 5.10.194-syzkaller-00508-ga27512601c2d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:452
 kasan_check_range+0x293/0x2a0 mm/kasan/generic.c:189
 memmove+0x2d/0x70 mm/kasan/shadow.c:54
 ext4_xattr_set_entry+0x1277/0x3a90 fs/ext4/xattr.c:1747
 ext4_xattr_ibody_set+0x124/0x390 fs/ext4/xattr.c:2228
 ext4_xattr_set_handle+0xc26/0x14e0 fs/ext4/xattr.c:2385
 ext4_xattr_set+0x231/0x3d0 fs/ext4/xattr.c:2498
 ext4_xattr_trusted_set+0x3b/0x50 fs/ext4/xattr_trusted.c:37
 __vfs_setxattr+0x404/0x450 fs/xattr.c:177
 __vfs_setxattr_noperm+0x11d/0x4f0 fs/xattr.c:208
 __vfs_setxattr_locked+0x1f9/0x210 fs/xattr.c:266
 vfs_setxattr+0x112/0x2c0 fs/xattr.c:283
 setxattr+0x1ea/0x3f0 fs/xattr.c:548
 path_setxattr+0x169/0x240 fs/xattr.c:567
 __do_sys_setxattr fs/xattr.c:582 [inline]
 __se_sys_setxattr fs/xattr.c:578 [inline]
 __x64_sys_setxattr+0xc5/0xe0 fs/xattr.c:578
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7fbc673511c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 18 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbc5ef2c218 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fbc673d96d8 RCX: 00007fbc673511c9
RDX: 0000000000000000 RSI: 0000000020000240 RDI: 00000000200002c0
RBP: 00007fbc673d96d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbc673a5a90
R13: 0031656c69662f2e R14: 00007ffcb1f7dc20 R15: 6f6f6c2f7665642f

The buggy address belongs to the page:
page:ffffea000470c940 refcount:3 mapcount:0 mapping:ffff88810044ad10 index:0x2 pfn:0x11c325
aops:def_blk_aops ino:0
flags: 0x4000000000002026(referenced|uptodate|active|private)
raw: 4000000000002026 dead000000000100 dead000000000122 ffff88810044ad10
raw: 0000000000000002 ffff88811f84e9d8 00000003ffffffff ffff888100144000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff888100144000
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x108c48(GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE), pid 16157, ts 321218578083, free_ts 321215858150
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x166/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5346
 __alloc_pages include/linux/gfp.h:544 [inline]
 __alloc_pages_node include/linux/gfp.h:557 [inline]
 alloc_pages_node include/linux/gfp.h:571 [inline]
 alloc_pages include/linux/gfp.h:590 [inline]
 __page_cache_alloc include/linux/pagemap.h:290 [inline]
 pagecache_get_page+0x669/0x950 mm/filemap.c:1848
 find_or_create_page include/linux/pagemap.h:402 [inline]
 grow_dev_page fs/buffer.c:976 [inline]
 grow_buffers fs/buffer.c:1045 [inline]
 __getblk_slow fs/buffer.c:1072 [inline]
 __getblk_gfp+0x221/0x7e0 fs/buffer.c:1370
 sb_getblk include/linux/buffer_head.h:361 [inline]
 __ext4_get_inode_loc+0x4c2/0xbf0 fs/ext4/inode.c:4431
 __ext4_get_inode_loc_noinmem fs/ext4/inode.c:4541 [inline]
 __ext4_iget+0x516/0x41f0 fs/ext4/inode.c:4766
 ext4_orphan_get+0x1e3/0x630 fs/ext4/ialloc.c:1391
 ext4_orphan_cleanup+0x696/0xd50 fs/ext4/super.c:3083
 ext4_fill_super+0x888c/0x9150 fs/ext4/super.c:5075
 mount_bdev+0x262/0x370 fs/super.c:1429
 ext4_mount+0x34/0x40 fs/ext4/super.c:6626
 legacy_get_tree+0xf1/0x190 fs/fs_context.c:593
 vfs_get_tree+0x88/0x290 fs/super.c:1559
 do_new_mount+0x28b/0xad0 fs/namespace.c:2899
 path_mount+0x56f/0xcb0 fs/namespace.c:3229
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 free_pcp_prepare mm/page_alloc.c:1421 [inline]
 free_unref_page_prepare+0x2ae/0x2d0 mm/page_alloc.c:3336
 free_unref_page_list+0x122/0xb20 mm/page_alloc.c:3443
 release_pages+0xea0/0xef0 mm/swap.c:1103
 free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:356
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
 tlb_flush_mmu mm/mmu_gather.c:247 [inline]
 tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:326
 unmap_region+0x31c/0x370 mm/mmap.c:2807
 __do_munmap+0x699/0x8c0 mm/mmap.c:3036
 __vm_munmap mm/mmap.c:3059 [inline]
 __do_sys_munmap mm/mmap.c:3085 [inline]
 __se_sys_munmap+0x120/0x1a0 mm/mmap.c:3081
 __x64_sys_munmap+0x5b/0x70 mm/mmap.c:3081
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

Memory state around the buggy address:
 ffff88811c325180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811c325200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88811c325280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                                          ^
 ffff88811c325300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88811c325380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================
EXT4-fs warning (device loop0): ext4_update_dynamic_rev:1047: updating to rev 1 because of new feature flag, running e2fsck is recommended

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/09/20 02:39 android13-5.10-lts a27512601c2d 0b6a67ac .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] [mounted in repro #3] ci2-android-5-10 KASAN: out-of-bounds Read in ext4_xattr_set_entry
* Struck through repros no longer work on HEAD.