| Message ID | 20220509145949.265184-1-eric.dumazet@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/page_owner: use strscpy() instead of strlcpy() | expand |
On 5/9/22 10:59, Eric Dumazet wrote: > From: Eric Dumazet <edumazet@google.com> > > current->comm[] is not a string (no guarantee for > a zero byte in it). > > strlcpy(s1, s2, l) is calling strlen(s2), potentially > causing out-of-bound access, as reported by syzbot: > > detected buffer overflow in __fortify_strlen > ------------[ cut here ]------------ > kernel BUG at lib/string_helpers.c:980! > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 4087 Comm: dhcpcd-run-hooks Not tainted 5.18.0-rc3-syzkaller-01537-g20b87e7c29df #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:fortify_panic+0x18/0x1a lib/string_helpers.c:980 > Code: 8c e8 c5 ba e1 fa e9 23 0f bf fa e8 0b 5d 8c f8 eb db 55 48 89 fd e8 e0 49 40 f8 48 89 ee 48 c7 c7 80 f5 26 8a e8 99 09 f1 ff <0f> 0b e8 ca 49 40 f8 48 8b 54 24 18 4c 89 f1 48 c7 c7 00 00 27 8a > RSP: 0018:ffffc900000074a8 EFLAGS: 00010286 > > RAX: 000000000000002c RBX: ffff88801226b728 RCX: 0000000000000000 > RDX: ffff8880198e0000 RSI: ffffffff81600458 RDI: fffff52000000e87 > RBP: ffffffff89da2aa0 R08: 000000000000002c R09: 0000000000000000 > R10: ffffffff815fae2e R11: 0000000000000000 R12: ffff88801226b700 > R13: ffff8880198e0830 R14: 0000000000000000 R15: 0000000000000000 > FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f5876ad6ff8 CR3: 000000001a48c000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > Call Trace: > <IRQ> > __fortify_strlen include/linux/fortify-string.h:128 [inline] > strlcpy include/linux/fortify-string.h:143 [inline] > __set_page_owner_handle+0x2b1/0x3e0 mm/page_owner.c:171 > __set_page_owner+0x3e/0x50 mm/page_owner.c:190 > prep_new_page mm/page_alloc.c:2441 [inline] > get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4182 > __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408 > alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272 > alloc_slab_page mm/slub.c:1799 [inline] > allocate_slab+0x26c/0x3c0 mm/slub.c:1944 > new_slab mm/slub.c:2004 [inline] > ___slab_alloc+0x8df/0xf20 mm/slub.c:3005 > __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3092 > slab_alloc_node mm/slub.c:3183 [inline] > slab_alloc mm/slub.c:3225 [inline] > __kmem_cache_alloc_lru mm/slub.c:3232 [inline] > kmem_cache_alloc+0x360/0x3b0 mm/slub.c:3242 > dst_alloc+0x146/0x1f0 net/core/dst.c:92 > > Fixes: 865ed6a32786 ("mm/page_owner: record task command name") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > Cc: Waiman Long <longman@redhat.com> > --- > mm/page_owner.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/page_owner.c b/mm/page_owner.c > index fb3a05fdebdbf1c3646ba1584cbf06facf0e7a9a..19bc559e49040e60c03a5f4268c89618fa0f1b1c 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -168,7 +168,7 @@ static inline void __set_page_owner_handle(struct page_ext *page_ext, > page_owner->pid = current->pid; > page_owner->tgid = current->tgid; > page_owner->ts_nsec = local_clock(); > - strlcpy(page_owner->comm, current->comm, > + strscpy(page_owner->comm, current->comm, > sizeof(page_owner->comm)); > __set_bit(PAGE_EXT_OWNER, &page_ext->flags); > __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); Yes, I think it is more correct to use strscpy(). Acked-by: Waiman Long <longman@redhat.com> Thanks, Longman
On Mon, May 09, 2022 at 07:59:49AM -0700, Eric Dumazet wrote: > From: Eric Dumazet <edumazet@google.com> > > current->comm[] is not a string (no guarantee for > a zero byte in it). > > strlcpy(s1, s2, l) is calling strlen(s2), potentially > causing out-of-bound access, as reported by syzbot: > > detected buffer overflow in __fortify_strlen > ------------[ cut here ]------------ > kernel BUG at lib/string_helpers.c:980! > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 4087 Comm: dhcpcd-run-hooks Not tainted 5.18.0-rc3-syzkaller-01537-g20b87e7c29df #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:fortify_panic+0x18/0x1a lib/string_helpers.c:980 > Code: 8c e8 c5 ba e1 fa e9 23 0f bf fa e8 0b 5d 8c f8 eb db 55 48 89 fd e8 e0 49 40 f8 48 89 ee 48 c7 c7 80 f5 26 8a e8 99 09 f1 ff <0f> 0b e8 ca 49 40 f8 48 8b 54 24 18 4c 89 f1 48 c7 c7 00 00 27 8a > RSP: 0018:ffffc900000074a8 EFLAGS: 00010286 > > RAX: 000000000000002c RBX: ffff88801226b728 RCX: 0000000000000000 > RDX: ffff8880198e0000 RSI: ffffffff81600458 RDI: fffff52000000e87 > RBP: ffffffff89da2aa0 R08: 000000000000002c R09: 0000000000000000 > R10: ffffffff815fae2e R11: 0000000000000000 R12: ffff88801226b700 > R13: ffff8880198e0830 R14: 0000000000000000 R15: 0000000000000000 > FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f5876ad6ff8 CR3: 000000001a48c000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 > Call Trace: > <IRQ> > __fortify_strlen include/linux/fortify-string.h:128 [inline] > strlcpy include/linux/fortify-string.h:143 [inline] > __set_page_owner_handle+0x2b1/0x3e0 mm/page_owner.c:171 > __set_page_owner+0x3e/0x50 mm/page_owner.c:190 > prep_new_page mm/page_alloc.c:2441 [inline] > get_page_from_freelist+0xba2/0x3e00 mm/page_alloc.c:4182 > __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5408 > alloc_pages+0x1aa/0x310 mm/mempolicy.c:2272 > alloc_slab_page mm/slub.c:1799 [inline] > allocate_slab+0x26c/0x3c0 mm/slub.c:1944 > new_slab mm/slub.c:2004 [inline] > ___slab_alloc+0x8df/0xf20 mm/slub.c:3005 > __slab_alloc.constprop.0+0x4d/0xa0 mm/slub.c:3092 > slab_alloc_node mm/slub.c:3183 [inline] > slab_alloc mm/slub.c:3225 [inline] > __kmem_cache_alloc_lru mm/slub.c:3232 [inline] > kmem_cache_alloc+0x360/0x3b0 mm/slub.c:3242 > dst_alloc+0x146/0x1f0 net/core/dst.c:92 > > Fixes: 865ed6a32786 ("mm/page_owner: record task command name") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > Cc: Waiman Long <longman@redhat.com> Acked-by: Shakeel Butt <shakeelb@google.com>
diff --git a/mm/page_owner.c b/mm/page_owner.c index fb3a05fdebdbf1c3646ba1584cbf06facf0e7a9a..19bc559e49040e60c03a5f4268c89618fa0f1b1c 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -168,7 +168,7 @@ static inline void __set_page_owner_handle(struct page_ext *page_ext, page_owner->pid = current->pid; page_owner->tgid = current->tgid; page_owner->ts_nsec = local_clock(); - strlcpy(page_owner->comm, current->comm, + strscpy(page_owner->comm, current->comm, sizeof(page_owner->comm)); __set_bit(PAGE_EXT_OWNER, &page_ext->flags); __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);