* KASAN: use-after-free Read in fuse_dev_do_read
@ 2018-09-13 8:00 syzbot
2018-09-13 8:51 ` Kirill Tkhai
2018-09-22 19:30 ` syzbot
0 siblings, 2 replies; 6+ messages in thread
From: syzbot @ 2018-09-13 8:00 UTC (permalink / raw)
To: linux-fsdevel, linux-kernel, miklos, syzkaller-bugs
Hello,
syzbot found the following crash on:
HEAD commit: 54eda9df17f3 Merge tag 'pci-v4.19-fixes-1' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=109a3d9e400000
kernel config: https://syzkaller.appspot.com/x/.config?x=b8f349d23d3c4835
dashboard link: https://syzkaller.appspot.com/bug?extid=4e975615ca01f2277bdd
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in constant_test_bit
arch/x86/include/asm/bitops.h:328 [inline]
BUG: KASAN: use-after-free in fuse_dev_do_read.isra.27+0x1659/0x1920
fs/fuse/dev.c:1318
Read of size 8 at addr ffff8801cbd4ea30 by task syz-executor0/28821
CPU: 1 PID: 28821 Comm: syz-executor0 Not tainted 4.19.0-rc3+ #11
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
constant_test_bit arch/x86/include/asm/bitops.h:328 [inline]
fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318
fuse_dev_read+0x1a9/0x250 fs/fuse/dev.c:1360
call_read_iter include/linux/fs.h:1801 [inline]
new_sync_read fs/read_write.c:406 [inline]
__vfs_read+0x6ac/0x9b0 fs/read_write.c:418
vfs_read+0x17f/0x3c0 fs/read_write.c:452
ksys_read+0x101/0x260 fs/read_write.c:578
__do_sys_read fs/read_write.c:588 [inline]
__se_sys_read fs/read_write.c:586 [inline]
__x64_sys_read+0x73/0xb0 fs/read_write.c:586
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4572d9
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007faaeefe4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007faaeefe56d4 RCX: 00000000004572d9
RDX: 0000000000001000 RSI: 00000000200040c0 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d4508 R14: 00000000004c8d44 R15: 0000000000000000
Allocated by task 28825:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554
__fuse_request_alloc+0x27/0xf0 fs/fuse/dev.c:58
fuse_request_alloc fs/fuse/dev.c:89 [inline]
__fuse_get_req+0x1f7/0x9e0 fs/fuse/dev.c:164
fuse_get_req fs/fuse/dev.c:194 [inline]
fuse_simple_request+0x28/0x730 fs/fuse/dev.c:549
fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442
statfs_by_dentry+0x136/0x210 fs/statfs.c:64
vfs_statfs+0x47/0x2e0 fs/statfs.c:74
user_statfs+0xbd/0x150 fs/statfs.c:89
__do_sys_statfs+0x7f/0xf0 fs/statfs.c:179
__se_sys_statfs fs/statfs.c:176 [inline]
__x64_sys_statfs+0x54/0x80 fs/statfs.c:176
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 28825:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kmem_cache_free+0x83/0x290 mm/slab.c:3756
fuse_request_free+0x8b/0xa0 fs/fuse/dev.c:104
fuse_put_request+0x2a6/0x350 fs/fuse/dev.c:304
fuse_simple_request+0x453/0x730 fs/fuse/dev.c:571
fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442
statfs_by_dentry+0x136/0x210 fs/statfs.c:64
vfs_statfs+0x47/0x2e0 fs/statfs.c:74
user_statfs+0xbd/0x150 fs/statfs.c:89
__do_sys_statfs+0x7f/0xf0 fs/statfs.c:179
__se_sys_statfs fs/statfs.c:176 [inline]
__x64_sys_statfs+0x54/0x80 fs/statfs.c:176
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The buggy address belongs to the object at ffff8801cbd4ea00
which belongs to the cache fuse_request of size 448
The buggy address is located 48 bytes inside of
448-byte region [ffff8801cbd4ea00, ffff8801cbd4ebc0)
The buggy address belongs to the page:
page:ffffea00072f5380 count:1 mapcount:0 mapping:ffff8801d4ad4840 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffffea000717eb48 ffff8801d4ad5c48 ffff8801d4ad4840
raw: 0000000000000000 ffff8801cbd4e000 0000000100000008 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801cbd4e900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8801cbd4e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8801cbd4ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801cbd4ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801cbd4eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: KASAN: use-after-free Read in fuse_dev_do_read 2018-09-13 8:00 KASAN: use-after-free Read in fuse_dev_do_read syzbot @ 2018-09-13 8:51 ` Kirill Tkhai 2018-09-13 8:59 ` Dmitry Vyukov 2018-09-22 19:30 ` syzbot 1 sibling, 1 reply; 6+ messages in thread From: Kirill Tkhai @ 2018-09-13 8:51 UTC (permalink / raw) To: syzbot, linux-fsdevel, linux-kernel, miklos, syzkaller-bugs Hi, On 13.09.2018 11:00, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 54eda9df17f3 Merge tag 'pci-v4.19-fixes-1' of git://git.ke.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=109a3d9e400000 what are requests id written here: write$FUSE_INIT(r0, &(0x7f0000000100)={0x50, 0x0, 0x1}, 0x50) write$FUSE_STATFS(r0, &(0x7f0000000040)={0x60, 0x0, 0x2, {{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xfffffffffffffffa}}}, 0x60) ? In case of parallel thread called write with id, we just queued to processing in fuse_dev_do_read(), we may bump to this stack (despite read has not finished yet, syzbot may write just everything, any id). fuse_dev_do_read() fuse_dev_do_write() list_move_tail(&req->list, &fpq->processing); ... spin_unlock(&fpq->lock); ... ... request_end(fc, req); ... fuse_put_request(fc, req); if (test_bit(FR_INTERRUPTED, &req->flags)) queue_interrupt(fiq, req); We should keep req refcount in fuse_dev_do_read(), till we haven't finished to use it. Something like this (compile tested only): diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 11ea2c4a38ab..675caed3e655 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1311,12 +1311,14 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, goto out_end; } list_move_tail(&req->list, &fpq->processing); + __fuse_get_request(req); spin_unlock(&fpq->lock); set_bit(FR_SENT, &req->flags); /* matches barrier in request_wait_answer() */ smp_mb__after_atomic(); if (test_bit(FR_INTERRUPTED, &req->flags)) queue_interrupt(fiq, req); + fuse_put_request(fc, req); return reqsize; > kernel config: https://syzkaller.appspot.com/x/.config?x=b8f349d23d3c4835 > dashboard link: https://syzkaller.appspot.com/bug?extid=4e975615ca01f2277bdd > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com > > ================================================================== > BUG: KASAN: use-after-free in constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] > BUG: KASAN: use-after-free in fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 > Read of size 8 at addr ffff8801cbd4ea30 by task syz-executor0/28821 > > CPU: 1 PID: 28821 Comm: syz-executor0 Not tainted 4.19.0-rc3+ #11 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 > print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] > fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 > fuse_dev_read+0x1a9/0x250 fs/fuse/dev.c:1360 > call_read_iter include/linux/fs.h:1801 [inline] > new_sync_read fs/read_write.c:406 [inline] > __vfs_read+0x6ac/0x9b0 fs/read_write.c:418 > vfs_read+0x17f/0x3c0 fs/read_write.c:452 > ksys_read+0x101/0x260 fs/read_write.c:578 > __do_sys_read fs/read_write.c:588 [inline] > __se_sys_read fs/read_write.c:586 [inline] > __x64_sys_read+0x73/0xb0 fs/read_write.c:586 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x4572d9 > Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007faaeefe4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > RAX: ffffffffffffffda RBX: 00007faaeefe56d4 RCX: 00000000004572d9 > RDX: 0000000000001000 RSI: 00000000200040c0 RDI: 0000000000000003 > RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000004d4508 R14: 00000000004c8d44 R15: 0000000000000000 > > Allocated by task 28825: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 > kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 > __fuse_request_alloc+0x27/0xf0 fs/fuse/dev.c:58 > fuse_request_alloc fs/fuse/dev.c:89 [inline] > __fuse_get_req+0x1f7/0x9e0 fs/fuse/dev.c:164 > fuse_get_req fs/fuse/dev.c:194 [inline] > fuse_simple_request+0x28/0x730 fs/fuse/dev.c:549 > fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442 > statfs_by_dentry+0x136/0x210 fs/statfs.c:64 > vfs_statfs+0x47/0x2e0 fs/statfs.c:74 > user_statfs+0xbd/0x150 fs/statfs.c:89 > __do_sys_statfs+0x7f/0xf0 fs/statfs.c:179 > __se_sys_statfs fs/statfs.c:176 [inline] > __x64_sys_statfs+0x54/0x80 fs/statfs.c:176 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 28825: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kmem_cache_free+0x83/0x290 mm/slab.c:3756 > fuse_request_free+0x8b/0xa0 fs/fuse/dev.c:104 > fuse_put_request+0x2a6/0x350 fs/fuse/dev.c:304 > fuse_simple_request+0x453/0x730 fs/fuse/dev.c:571 > fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442 > statfs_by_dentry+0x136/0x210 fs/statfs.c:64 > vfs_statfs+0x47/0x2e0 fs/statfs.c:74 > user_statfs+0xbd/0x150 fs/statfs.c:89 > __do_sys_statfs+0x7f/0xf0 fs/statfs.c:179 > __se_sys_statfs fs/statfs.c:176 [inline] > __x64_sys_statfs+0x54/0x80 fs/statfs.c:176 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8801cbd4ea00 > which belongs to the cache fuse_request of size 448 > The buggy address is located 48 bytes inside of > 448-byte region [ffff8801cbd4ea00, ffff8801cbd4ebc0) > The buggy address belongs to the page: > page:ffffea00072f5380 count:1 mapcount:0 mapping:ffff8801d4ad4840 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea000717eb48 ffff8801d4ad5c48 ffff8801d4ad4840 > raw: 0000000000000000 ffff8801cbd4e000 0000000100000008 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801cbd4e900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff8801cbd4e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff8801cbd4ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8801cbd4ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801cbd4eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: KASAN: use-after-free Read in fuse_dev_do_read 2018-09-13 8:51 ` Kirill Tkhai @ 2018-09-13 8:59 ` Dmitry Vyukov 0 siblings, 0 replies; 6+ messages in thread From: Dmitry Vyukov @ 2018-09-13 8:59 UTC (permalink / raw) To: Kirill Tkhai; +Cc: syzbot, linux-fsdevel, LKML, Miklos Szeredi, syzkaller-bugs On Thu, Sep 13, 2018 at 10:51 AM, Kirill Tkhai <ktkhai@virtuozzo.com> wrote: > Hi, > > On 13.09.2018 11:00, syzbot wrote: >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: 54eda9df17f3 Merge tag 'pci-v4.19-fixes-1' of git://git.ke.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=109a3d9e400000 > > what are requests id written here: > > write$FUSE_INIT(r0, &(0x7f0000000100)={0x50, 0x0, 0x1}, 0x50) > write$FUSE_STATFS(r0, &(0x7f0000000040)={0x60, 0x0, 0x2, {{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0xfffffffffffffffa}}}, 0x60) > > ? Hi Kirill, It may be easier to contrast these numbers with struct definitions here: https://github.com/google/syzkaller/blob/master/sys/linux/fuse.txt But passing this fragment through syskaller's tools/syz-prog2c gives me the following (exact binary layout: int main(void) { syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0); *(uint32_t*)0x20000100 = 0x50; *(uint32_t*)0x20000104 = 0; *(uint64_t*)0x20000108 = 1; *(uint32_t*)0x20000110 = 7; *(uint32_t*)0x20000114 = 0x1b; *(uint32_t*)0x20000118 = 0; *(uint32_t*)0x2000011c = 0; *(uint16_t*)0x20000120 = 0; *(uint16_t*)0x20000122 = 0; *(uint32_t*)0x20000124 = 0; *(uint32_t*)0x20000128 = 0; *(uint32_t*)0x2000012c = 0; *(uint32_t*)0x20000130 = 0; *(uint32_t*)0x20000134 = 0; *(uint32_t*)0x20000138 = 0; *(uint32_t*)0x2000013c = 0; *(uint32_t*)0x20000140 = 0; *(uint32_t*)0x20000144 = 0; *(uint32_t*)0x20000148 = 0; *(uint32_t*)0x2000014c = 0; syscall(__NR_write, -1, 0x20000100, 0x50); *(uint32_t*)0x20000040 = 0x60; *(uint32_t*)0x20000044 = 0; *(uint64_t*)0x20000048 = 2; *(uint64_t*)0x20000050 = 0; *(uint64_t*)0x20000058 = 0; *(uint64_t*)0x20000060 = 0; *(uint64_t*)0x20000068 = 0; *(uint64_t*)0x20000070 = 0; *(uint32_t*)0x20000078 = 0; *(uint32_t*)0x2000007c = 0; *(uint32_t*)0x20000080 = 0xfffffffa; *(uint32_t*)0x20000084 = 0; *(uint32_t*)0x20000088 = 0; *(uint32_t*)0x2000008c = 0; *(uint32_t*)0x20000090 = 0; *(uint32_t*)0x20000094 = 0; *(uint32_t*)0x20000098 = 0; *(uint32_t*)0x2000009c = 0; syscall(__NR_write, -1, 0x20000040, 0x60); return 0; } For request IDs syzkaller just chooses random numbers in 1:8 range: type fuse_out[PAYLOAD] { len len[parent, int32] err flags[fuse_errors, int32] unique fuse_unique payload PAYLOAD } [packed] type fuse_unique int64[1:8] > In case of parallel thread called write with id, we just queued to processing > in fuse_dev_do_read(), we may bump to this stack (despite read has not finished > yet, syzbot may write just everything, any id). > > fuse_dev_do_read() fuse_dev_do_write() > list_move_tail(&req->list, &fpq->processing); ... > spin_unlock(&fpq->lock); ... > ... request_end(fc, req); > ... fuse_put_request(fc, req); > if (test_bit(FR_INTERRUPTED, &req->flags)) > queue_interrupt(fiq, req); > > We should keep req refcount in fuse_dev_do_read(), till we haven't finished to use it. > Something like this (compile tested only): > > diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c > index 11ea2c4a38ab..675caed3e655 100644 > --- a/fs/fuse/dev.c > +++ b/fs/fuse/dev.c > @@ -1311,12 +1311,14 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, > goto out_end; > } > list_move_tail(&req->list, &fpq->processing); > + __fuse_get_request(req); > spin_unlock(&fpq->lock); > set_bit(FR_SENT, &req->flags); > /* matches barrier in request_wait_answer() */ > smp_mb__after_atomic(); > if (test_bit(FR_INTERRUPTED, &req->flags)) > queue_interrupt(fiq, req); > + fuse_put_request(fc, req); > > return reqsize; > > > >> kernel config: https://syzkaller.appspot.com/x/.config?x=b8f349d23d3c4835 >> dashboard link: https://syzkaller.appspot.com/bug?extid=4e975615ca01f2277bdd >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> >> Unfortunately, I don't have any reproducer for this crash yet. >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com >> >> ================================================================== >> BUG: KASAN: use-after-free in constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] >> BUG: KASAN: use-after-free in fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 >> Read of size 8 at addr ffff8801cbd4ea30 by task syz-executor0/28821 >> >> CPU: 1 PID: 28821 Comm: syz-executor0 Not tainted 4.19.0-rc3+ #11 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 >> Call Trace: >> __dump_stack lib/dump_stack.c:77 [inline] >> dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 >> print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 >> kasan_report_error mm/kasan/report.c:354 [inline] >> kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 >> __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 >> constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] >> fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 >> fuse_dev_read+0x1a9/0x250 fs/fuse/dev.c:1360 >> call_read_iter include/linux/fs.h:1801 [inline] >> new_sync_read fs/read_write.c:406 [inline] >> __vfs_read+0x6ac/0x9b0 fs/read_write.c:418 >> vfs_read+0x17f/0x3c0 fs/read_write.c:452 >> ksys_read+0x101/0x260 fs/read_write.c:578 >> __do_sys_read fs/read_write.c:588 [inline] >> __se_sys_read fs/read_write.c:586 [inline] >> __x64_sys_read+0x73/0xb0 fs/read_write.c:586 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x4572d9 >> Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 >> RSP: 002b:00007faaeefe4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 >> RAX: ffffffffffffffda RBX: 00007faaeefe56d4 RCX: 00000000004572d9 >> RDX: 0000000000001000 RSI: 00000000200040c0 RDI: 0000000000000003 >> RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff >> R13: 00000000004d4508 R14: 00000000004c8d44 R15: 0000000000000000 >> >> Allocated by task 28825: >> save_stack+0x43/0xd0 mm/kasan/kasan.c:448 >> set_track mm/kasan/kasan.c:460 [inline] >> kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 >> kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 >> kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 >> __fuse_request_alloc+0x27/0xf0 fs/fuse/dev.c:58 >> fuse_request_alloc fs/fuse/dev.c:89 [inline] >> __fuse_get_req+0x1f7/0x9e0 fs/fuse/dev.c:164 >> fuse_get_req fs/fuse/dev.c:194 [inline] >> fuse_simple_request+0x28/0x730 fs/fuse/dev.c:549 >> fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442 >> statfs_by_dentry+0x136/0x210 fs/statfs.c:64 >> vfs_statfs+0x47/0x2e0 fs/statfs.c:74 >> user_statfs+0xbd/0x150 fs/statfs.c:89 >> __do_sys_statfs+0x7f/0xf0 fs/statfs.c:179 >> __se_sys_statfs fs/statfs.c:176 [inline] >> __x64_sys_statfs+0x54/0x80 fs/statfs.c:176 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> >> Freed by task 28825: >> save_stack+0x43/0xd0 mm/kasan/kasan.c:448 >> set_track mm/kasan/kasan.c:460 [inline] >> __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 >> kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 >> __cache_free mm/slab.c:3498 [inline] >> kmem_cache_free+0x83/0x290 mm/slab.c:3756 >> fuse_request_free+0x8b/0xa0 fs/fuse/dev.c:104 >> fuse_put_request+0x2a6/0x350 fs/fuse/dev.c:304 >> fuse_simple_request+0x453/0x730 fs/fuse/dev.c:571 >> fuse_statfs+0x368/0x8a0 fs/fuse/inode.c:442 >> statfs_by_dentry+0x136/0x210 fs/statfs.c:64 >> vfs_statfs+0x47/0x2e0 fs/statfs.c:74 >> user_statfs+0xbd/0x150 fs/statfs.c:89 >> __do_sys_statfs+0x7f/0xf0 fs/statfs.c:179 >> __se_sys_statfs fs/statfs.c:176 [inline] >> __x64_sys_statfs+0x54/0x80 fs/statfs.c:176 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> >> The buggy address belongs to the object at ffff8801cbd4ea00 >> which belongs to the cache fuse_request of size 448 >> The buggy address is located 48 bytes inside of >> 448-byte region [ffff8801cbd4ea00, ffff8801cbd4ebc0) >> The buggy address belongs to the page: >> page:ffffea00072f5380 count:1 mapcount:0 mapping:ffff8801d4ad4840 index:0x0 >> flags: 0x2fffc0000000100(slab) >> raw: 02fffc0000000100 ffffea000717eb48 ffff8801d4ad5c48 ffff8801d4ad4840 >> raw: 0000000000000000 ffff8801cbd4e000 0000000100000008 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ffff8801cbd4e900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff8801cbd4e980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>> ffff8801cbd4ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ^ >> ffff8801cbd4ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ffff8801cbd4eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ================================================================== >> >> >> --- >> This bug is generated by a bot. It may contain errors. >> See https://goo.gl/tpsmEJ for more information about syzbot. >> syzbot engineers can be reached at syzkaller@googlegroups.com. >> >> syzbot will keep track of this bug report. See: >> https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/5882d989-8e9d-0ae1-1b2d-3ba431e97eb6%40virtuozzo.com. > For more options, visit https://groups.google.com/d/optout. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KASAN: use-after-free Read in fuse_dev_do_read 2018-09-13 8:00 KASAN: use-after-free Read in fuse_dev_do_read syzbot 2018-09-13 8:51 ` Kirill Tkhai @ 2018-09-22 19:30 ` syzbot 2018-09-24 12:06 ` Kirill Tkhai 1 sibling, 1 reply; 6+ messages in thread From: syzbot @ 2018-09-22 19:30 UTC (permalink / raw) To: dvyukov, ktkhai, linux-fsdevel, linux-kernel, miklos, syzkaller-bugs syzbot has found a reproducer for the following crash on: HEAD commit: 10dc890d4228 Merge tag 'pinctrl-v4.19-3' of git://git.kern.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1631cfbe400000 kernel config: https://syzkaller.appspot.com/x/.config?x=5fa12be50bca08d8 dashboard link: https://syzkaller.appspot.com/bug?extid=4e975615ca01f2277bdd compiler: gcc (GCC) 8.0.1 20180413 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15ffb766400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com 8021q: adding VLAN 0 to HW filter on device team0 8021q: adding VLAN 0 to HW filter on device team0 8021q: adding VLAN 0 to HW filter on device team0 8021q: adding VLAN 0 to HW filter on device team0 ================================================================== BUG: KASAN: use-after-free in constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] BUG: KASAN: use-after-free in fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 Read of size 8 at addr ffff8801d8702630 by task syz-executor1/7794 CPU: 0 PID: 7794 Comm: syz-executor1 Not tainted 4.19.0-rc4+ #26 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 fuse_dev_read+0x1a9/0x250 fs/fuse/dev.c:1360 call_read_iter include/linux/fs.h:1802 [inline] new_sync_read fs/read_write.c:406 [inline] __vfs_read+0x6ac/0x9b0 fs/read_write.c:418 vfs_read+0x17f/0x3c0 fs/read_write.c:452 ksys_read+0x101/0x260 fs/read_write.c:578 __do_sys_read fs/read_write.c:588 [inline] __se_sys_read fs/read_write.c:586 [inline] __x64_sys_read+0x73/0xb0 fs/read_write.c:586 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457679 Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f6a5aeedc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f6a5aeee6d4 RCX: 0000000000457679 RDX: 0000000000001000 RSI: 0000000020001000 RDI: 0000000000000003 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d4ad0 R14: 00000000004c31e5 R15: 0000000000000000 Allocated by task 7801: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 __fuse_request_alloc+0x27/0xf0 fs/fuse/dev.c:58 fuse_request_alloc+0x18/0x20 fs/fuse/dev.c:89 fuse_fill_super+0x12bf/0x1ea0 fs/fuse/inode.c:1157 mount_nodev+0x6b/0x110 fs/super.c:1204 fuse_mount+0x2c/0x40 fs/fuse/inode.c:1213 mount_fs+0xae/0x31d fs/super.c:1261 vfs_kern_mount.part.35+0xdc/0x4f0 fs/namespace.c:961 vfs_kern_mount fs/namespace.c:951 [inline] do_new_mount fs/namespace.c:2457 [inline] do_mount+0x581/0x31f0 fs/namespace.c:2787 ksys_mount+0x12d/0x140 fs/namespace.c:3003 __do_sys_mount fs/namespace.c:3017 [inline] __se_sys_mount fs/namespace.c:3014 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3014 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 7801: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x83/0x290 mm/slab.c:3756 fuse_request_free+0x8b/0xa0 fs/fuse/dev.c:104 fuse_put_request+0x2a6/0x350 fs/fuse/dev.c:304 request_end+0xba/0xaa0 fs/fuse/dev.c:414 fuse_dev_do_write+0x192e/0x36e0 fs/fuse/dev.c:1915 fuse_dev_write+0x19a/0x240 fs/fuse/dev.c:1939 call_write_iter include/linux/fs.h:1808 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x6b8/0x9f0 fs/read_write.c:487 vfs_write+0x1fc/0x560 fs/read_write.c:549 ksys_write+0x101/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff8801d8702600 which belongs to the cache fuse_request of size 448 The buggy address is located 48 bytes inside of 448-byte region [ffff8801d8702600, ffff8801d87027c0) The buggy address belongs to the page: page:ffffea000761c080 count:1 mapcount:0 mapping:ffff8801d4a0e240 index:0x0 flags: 0x2fffc0000000100(slab) raw: 02fffc0000000100 ffffea0006ec0e88 ffffea0006ee91c8 ffff8801d4a0e240 raw: 0000000000000000 ffff8801d8702000 0000000100000008 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8801d8702500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d8702580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801d8702600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8801d8702680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8801d8702700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: KASAN: use-after-free Read in fuse_dev_do_read 2018-09-22 19:30 ` syzbot @ 2018-09-24 12:06 ` Kirill Tkhai 2018-09-24 14:27 ` Miklos Szeredi 0 siblings, 1 reply; 6+ messages in thread From: Kirill Tkhai @ 2018-09-24 12:06 UTC (permalink / raw) To: syzbot, dvyukov, linux-fsdevel, linux-kernel, miklos, syzkaller-bugs On 22.09.2018 22:30, syzbot wrote: > syzbot has found a reproducer for the following crash on: > > HEAD commit: 10dc890d4228 Merge tag 'pinctrl-v4.19-3' of git://git.kern.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1631cfbe400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5fa12be50bca08d8 > dashboard link: https://syzkaller.appspot.com/bug?extid=4e975615ca01f2277bdd > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15ffb766400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+4e975615ca01f2277bdd@syzkaller.appspotmail.com > > 8021q: adding VLAN 0 to HW filter on device team0 > 8021q: adding VLAN 0 to HW filter on device team0 > 8021q: adding VLAN 0 to HW filter on device team0 > 8021q: adding VLAN 0 to HW filter on device team0 > ================================================================== > BUG: KASAN: use-after-free in constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] > BUG: KASAN: use-after-free in fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 > Read of size 8 at addr ffff8801d8702630 by task syz-executor1/7794 > > CPU: 0 PID: 7794 Comm: syz-executor1 Not tainted 4.19.0-rc4+ #26 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113 > print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 > constant_test_bit arch/x86/include/asm/bitops.h:328 [inline] > fuse_dev_do_read.isra.27+0x1659/0x1920 fs/fuse/dev.c:1318 > fuse_dev_read+0x1a9/0x250 fs/fuse/dev.c:1360 > call_read_iter include/linux/fs.h:1802 [inline] > new_sync_read fs/read_write.c:406 [inline] > __vfs_read+0x6ac/0x9b0 fs/read_write.c:418 > vfs_read+0x17f/0x3c0 fs/read_write.c:452 > ksys_read+0x101/0x260 fs/read_write.c:578 > __do_sys_read fs/read_write.c:588 [inline] > __se_sys_read fs/read_write.c:586 [inline] > __x64_sys_read+0x73/0xb0 fs/read_write.c:586 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x457679 > Code: 1d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f6a5aeedc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > RAX: ffffffffffffffda RBX: 00007f6a5aeee6d4 RCX: 0000000000457679 > RDX: 0000000000001000 RSI: 0000000020001000 RDI: 0000000000000003 > RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000004d4ad0 R14: 00000000004c31e5 R15: 0000000000000000 > > Allocated by task 7801: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553 > kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 > kmem_cache_alloc+0x12e/0x730 mm/slab.c:3554 > __fuse_request_alloc+0x27/0xf0 fs/fuse/dev.c:58 > fuse_request_alloc+0x18/0x20 fs/fuse/dev.c:89 > fuse_fill_super+0x12bf/0x1ea0 fs/fuse/inode.c:1157 > mount_nodev+0x6b/0x110 fs/super.c:1204 > fuse_mount+0x2c/0x40 fs/fuse/inode.c:1213 > mount_fs+0xae/0x31d fs/super.c:1261 > vfs_kern_mount.part.35+0xdc/0x4f0 fs/namespace.c:961 > vfs_kern_mount fs/namespace.c:951 [inline] > do_new_mount fs/namespace.c:2457 [inline] > do_mount+0x581/0x31f0 fs/namespace.c:2787 > ksys_mount+0x12d/0x140 fs/namespace.c:3003 > __do_sys_mount fs/namespace.c:3017 [inline] > __se_sys_mount fs/namespace.c:3014 [inline] > __x64_sys_mount+0xbe/0x150 fs/namespace.c:3014 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 7801: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kmem_cache_free+0x83/0x290 mm/slab.c:3756 > fuse_request_free+0x8b/0xa0 fs/fuse/dev.c:104 > fuse_put_request+0x2a6/0x350 fs/fuse/dev.c:304 > request_end+0xba/0xaa0 fs/fuse/dev.c:414 > fuse_dev_do_write+0x192e/0x36e0 fs/fuse/dev.c:1915 > fuse_dev_write+0x19a/0x240 fs/fuse/dev.c:1939 > call_write_iter include/linux/fs.h:1808 [inline] > new_sync_write fs/read_write.c:474 [inline] > __vfs_write+0x6b8/0x9f0 fs/read_write.c:487 > vfs_write+0x1fc/0x560 fs/read_write.c:549 > ksys_write+0x101/0x260 fs/read_write.c:598 > __do_sys_write fs/read_write.c:610 [inline] > __se_sys_write fs/read_write.c:607 [inline] > __x64_sys_write+0x73/0xb0 fs/read_write.c:607 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8801d8702600 > which belongs to the cache fuse_request of size 448 > The buggy address is located 48 bytes inside of > 448-byte region [ffff8801d8702600, ffff8801d87027c0) > The buggy address belongs to the page: > page:ffffea000761c080 count:1 mapcount:0 mapping:ffff8801d4a0e240 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea0006ec0e88 ffffea0006ee91c8 ffff8801d4a0e240 > raw: 0000000000000000 ffff8801d8702000 0000000100000008 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801d8702500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801d8702580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >> ffff8801d8702600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8801d8702680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff8801d8702700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== Fix from my previous message makes the use-after-free does not reproduce with the reproducer in my setup. I can prepare the patch, but before this some comments from Miklos would be welcome. Miklos, what you think about this? Kirill --- diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 11ea2c4a38ab..675caed3e655 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -1311,12 +1311,14 @@ static ssize_t fuse_dev_do_read(struct fuse_dev *fud, struct file *file, goto out_end; } list_move_tail(&req->list, &fpq->processing); + __fuse_get_request(req); spin_unlock(&fpq->lock); set_bit(FR_SENT, &req->flags); /* matches barrier in request_wait_answer() */ smp_mb__after_atomic(); if (test_bit(FR_INTERRUPTED, &req->flags)) queue_interrupt(fiq, req); + fuse_put_request(fc, req); return reqsize; ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: KASAN: use-after-free Read in fuse_dev_do_read 2018-09-24 12:06 ` Kirill Tkhai @ 2018-09-24 14:27 ` Miklos Szeredi 0 siblings, 0 replies; 6+ messages in thread From: Miklos Szeredi @ 2018-09-24 14:27 UTC (permalink / raw) To: Kirill Tkhai Cc: syzbot, Dmitry Vyukov, linux-fsdevel, linux-kernel, syzkaller-bugs On Mon, Sep 24, 2018 at 2:06 PM, Kirill Tkhai <ktkhai@virtuozzo.com> wrote: > Fix from my previous message makes the use-after-free does not reproduce > with the reproducer in my setup. Excellent. > > I can prepare the patch, but before this some comments from Miklos would > be welcome. > > Miklos, what you think about this? I like the patch. We could optimize away the get/put by moving the set_bit/test_bit part inside the fpq->lock-ed region and only get the refcount for the (unlikely) interrupted case. OTOH it's probably not worth the extra complexity, so let's stay with this simpler fix. Thanks, Miklos ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2018-09-24 20:29 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-09-13 8:00 KASAN: use-after-free Read in fuse_dev_do_read syzbot 2018-09-13 8:51 ` Kirill Tkhai 2018-09-13 8:59 ` Dmitry Vyukov 2018-09-22 19:30 ` syzbot 2018-09-24 12:06 ` Kirill Tkhai 2018-09-24 14:27 ` Miklos Szeredi
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