| Message ID | 20200816141204.162624-1-shy828301@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: madvise: fix vma user-after-free | expand |
On Sun 16-08-20 07:12:04, Yang Shi wrote: > The syzbot reported the below use-after-free: > > BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline] > BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline] > BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 > Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996 > > CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0 > 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+0x18f/0x20d lib/dump_stack.c:118 > print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 > __kasan_report mm/kasan/report.c:513 [inline] > kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 > madvise_willneed mm/madvise.c:293 [inline] > madvise_vma mm/madvise.c:942 [inline] > do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 > do_madvise mm/madvise.c:1169 [inline] > __do_sys_madvise mm/madvise.c:1171 [inline] > __se_sys_madvise mm/madvise.c:1169 [inline] > __x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x45d4d9 > Code: 5d 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f04f7464c78 EFLAGS: 00000246 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 0000000000020800 RCX: 000000000045d4d9 > RDX: 0000000000000003 RSI: 0000000000600003 RDI: 0000000020000000 > RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec > R13: 00007ffc579cce7f R14: 00007f04f74659c0 R15: 000000000118cfec > > Allocated by task 9992: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 > kasan_set_track mm/kasan/common.c:56 [inline] > __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 > slab_post_alloc_hook mm/slab.h:518 [inline] > slab_alloc mm/slab.c:3312 [inline] > kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482 > vm_area_alloc+0x1c/0x110 kernel/fork.c:347 > mmap_region+0x8e5/0x1780 mm/mmap.c:1743 > do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 > vm_mmap_pgoff+0x195/0x200 mm/util.c:506 > ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Freed by task 9992: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 > kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 > kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 > __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 > __cache_free mm/slab.c:3418 [inline] > kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 > remove_vma+0x132/0x170 mm/mmap.c:184 > remove_vma_list mm/mmap.c:2613 [inline] > __do_munmap+0x743/0x1170 mm/mmap.c:2869 > do_munmap mm/mmap.c:2877 [inline] > mmap_region+0x257/0x1780 mm/mmap.c:1716 > do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 > vm_mmap_pgoff+0x195/0x200 mm/util.c:506 > ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > It is because vma is accessed after releasing mmap_sem, but someone else > acquired the mmap_sem and the vma is gone. > > Releasing mmap_sem after accessing vma should fix the problem. > > Fixes: 692fe62433d4c ("mm: Handle MADV_WILLNEED through vfs_fadvise()") > Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com > Cc: Jan Kara <jack@suse.cz> > Cc: <stable@vger.kernel.org> v5.4+ > Signed-off-by: Yang Shi <shy828301@gmail.com> Yeah, good catch! Thanks for fixing this. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > mm/madvise.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/madvise.c b/mm/madvise.c > index dd1d43cf026d..d4aa5f776543 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -289,9 +289,9 @@ static long madvise_willneed(struct vm_area_struct *vma, > */ > *prev = NULL; /* tell sys_madvise we drop mmap_lock */ > get_file(file); > - mmap_read_unlock(current->mm); > offset = (loff_t)(start - vma->vm_start) > + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); > + mmap_read_unlock(current->mm); > vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED); > fput(file); > mmap_read_lock(current->mm); > -- > 2.26.2 >
On 16.08.20 16:12, Yang Shi wrote: > The syzbot reported the below use-after-free: > > BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline] > BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline] > BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 > Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996 > > CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0 > 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+0x18f/0x20d lib/dump_stack.c:118 > print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 > __kasan_report mm/kasan/report.c:513 [inline] > kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 > madvise_willneed mm/madvise.c:293 [inline] > madvise_vma mm/madvise.c:942 [inline] > do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 > do_madvise mm/madvise.c:1169 [inline] > __do_sys_madvise mm/madvise.c:1171 [inline] > __se_sys_madvise mm/madvise.c:1169 [inline] > __x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x45d4d9 > Code: 5d 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f04f7464c78 EFLAGS: 00000246 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 0000000000020800 RCX: 000000000045d4d9 > RDX: 0000000000000003 RSI: 0000000000600003 RDI: 0000000020000000 > RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec > R13: 00007ffc579cce7f R14: 00007f04f74659c0 R15: 000000000118cfec > > Allocated by task 9992: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 > kasan_set_track mm/kasan/common.c:56 [inline] > __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 > slab_post_alloc_hook mm/slab.h:518 [inline] > slab_alloc mm/slab.c:3312 [inline] > kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482 > vm_area_alloc+0x1c/0x110 kernel/fork.c:347 > mmap_region+0x8e5/0x1780 mm/mmap.c:1743 > do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 > vm_mmap_pgoff+0x195/0x200 mm/util.c:506 > ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Freed by task 9992: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 > kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 > kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 > __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 > __cache_free mm/slab.c:3418 [inline] > kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 > remove_vma+0x132/0x170 mm/mmap.c:184 > remove_vma_list mm/mmap.c:2613 [inline] > __do_munmap+0x743/0x1170 mm/mmap.c:2869 > do_munmap mm/mmap.c:2877 [inline] > mmap_region+0x257/0x1780 mm/mmap.c:1716 > do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 > vm_mmap_pgoff+0x195/0x200 mm/util.c:506 > ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > It is because vma is accessed after releasing mmap_sem, but someone else > acquired the mmap_sem and the vma is gone. > > Releasing mmap_sem after accessing vma should fix the problem. > > Fixes: 692fe62433d4c ("mm: Handle MADV_WILLNEED through vfs_fadvise()") > Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com > Cc: Jan Kara <jack@suse.cz> > Cc: <stable@vger.kernel.org> v5.4+ > Signed-off-by: Yang Shi <shy828301@gmail.com> > --- > mm/madvise.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/madvise.c b/mm/madvise.c > index dd1d43cf026d..d4aa5f776543 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -289,9 +289,9 @@ static long madvise_willneed(struct vm_area_struct *vma, > */ > *prev = NULL; /* tell sys_madvise we drop mmap_lock */ > get_file(file); > - mmap_read_unlock(current->mm); > offset = (loff_t)(start - vma->vm_start) > + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); > + mmap_read_unlock(current->mm); > vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED); > fput(file); > mmap_read_lock(current->mm); > Late to the party, nice finding and fix Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/mm/madvise.c b/mm/madvise.c index dd1d43cf026d..d4aa5f776543 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -289,9 +289,9 @@ static long madvise_willneed(struct vm_area_struct *vma, */ *prev = NULL; /* tell sys_madvise we drop mmap_lock */ get_file(file); - mmap_read_unlock(current->mm); offset = (loff_t)(start - vma->vm_start) + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); + mmap_read_unlock(current->mm); vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED); fput(file); mmap_read_lock(current->mm);
The syzbot reported the below use-after-free: BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline] BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline] BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996 CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0 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+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 madvise_willneed mm/madvise.c:293 [inline] madvise_vma mm/madvise.c:942 [inline] do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 do_madvise mm/madvise.c:1169 [inline] __do_sys_madvise mm/madvise.c:1171 [inline] __se_sys_madvise mm/madvise.c:1169 [inline] __x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d4d9 Code: 5d 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f04f7464c78 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 0000000000020800 RCX: 000000000045d4d9 RDX: 0000000000000003 RSI: 0000000000600003 RDI: 0000000020000000 RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec R13: 00007ffc579cce7f R14: 00007f04f74659c0 R15: 000000000118cfec Allocated by task 9992: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482 vm_area_alloc+0x1c/0x110 kernel/fork.c:347 mmap_region+0x8e5/0x1780 mm/mmap.c:1743 do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 vm_mmap_pgoff+0x195/0x200 mm/util.c:506 ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 9992: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 remove_vma+0x132/0x170 mm/mmap.c:184 remove_vma_list mm/mmap.c:2613 [inline] __do_munmap+0x743/0x1170 mm/mmap.c:2869 do_munmap mm/mmap.c:2877 [inline] mmap_region+0x257/0x1780 mm/mmap.c:1716 do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 vm_mmap_pgoff+0x195/0x200 mm/util.c:506 ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 It is because vma is accessed after releasing mmap_sem, but someone else acquired the mmap_sem and the vma is gone. Releasing mmap_sem after accessing vma should fix the problem. Fixes: 692fe62433d4c ("mm: Handle MADV_WILLNEED through vfs_fadvise()") Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com Cc: Jan Kara <jack@suse.cz> Cc: <stable@vger.kernel.org> v5.4+ Signed-off-by: Yang Shi <shy828301@gmail.com> --- mm/madvise.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)