[PATCH -next v2] bpf: Add oversize check before call kvcalloc()

[PATCH -next v2] bpf: Add oversize check before call kvcalloc()

[Bixuan Cui]

Commit 7661809d493b ("mm: don't allow oversized kvmalloc() calls") add the
oversize check. When the allocation is larger than what kmalloc() supports,
the following warning triggered:

WARNING: CPU: 0 PID: 8408 at mm/util.c:597 kvmalloc_node+0x108/0x110 mm/util.c:597
Modules linked in:
CPU: 0 PID: 8408 Comm: syz-executor221 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kvmalloc_node+0x108/0x110 mm/util.c:597
Call Trace:
 kvmalloc include/linux/mm.h:806 [inline]
 kvmalloc_array include/linux/mm.h:824 [inline]
 kvcalloc include/linux/mm.h:829 [inline]
 check_btf_line kernel/bpf/verifier.c:9925 [inline]
 check_btf_info kernel/bpf/verifier.c:10049 [inline]
 bpf_check+0xd634/0x150d0 kernel/bpf/verifier.c:13759
 bpf_prog_load kernel/bpf/syscall.c:2301 [inline]
 __sys_bpf+0x11181/0x126e0 kernel/bpf/syscall.c:4587
 __do_sys_bpf kernel/bpf/syscall.c:4691 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4689 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4689
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported-by: syzbot+f3e749d4c662818ae439@syzkaller.appspotmail.com
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
---
Chang in v2:
* Change 'if (nr_linfo * sizeof(struct bpf_line_info) > INT_MAX)' to
  'if (nr_lifo > INT_MAX / sizeof(struct bpf_line_info))'.

 kernel/bpf/verifier.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index a0dd972d5b41..de006552be8a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9912,6 +9912,8 @@ static int check_btf_line(struct bpf_verifier_env *env,
 	nr_linfo = attr->line_info_cnt;
 	if (!nr_linfo)
 		return 0;
+	if (nr_linfo > INT_MAX / sizeof(struct bpf_line_info))
+		return -EINVAL;
 
 	rec_size = attr->line_info_rec_size;
 	if (rec_size < MIN_BPF_LINEINFO_SIZE ||
-- 
2.17.1

Re: [PATCH -next v2] bpf: Add oversize check before call kvcalloc()

[Yonghong Song]

On 9/10/21 5:55 PM, Bixuan Cui wrote:
> Commit 7661809d493b ("mm: don't allow oversized kvmalloc() calls") add the
> oversize check. When the allocation is larger than what kmalloc() supports,
> the following warning triggered:
> 
> WARNING: CPU: 0 PID: 8408 at mm/util.c:597 kvmalloc_node+0x108/0x110 mm/util.c:597
> Modules linked in:
> CPU: 0 PID: 8408 Comm: syz-executor221 Not tainted 5.14.0-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:kvmalloc_node+0x108/0x110 mm/util.c:597
> Call Trace:
>   kvmalloc include/linux/mm.h:806 [inline]
>   kvmalloc_array include/linux/mm.h:824 [inline]
>   kvcalloc include/linux/mm.h:829 [inline]
>   check_btf_line kernel/bpf/verifier.c:9925 [inline]
>   check_btf_info kernel/bpf/verifier.c:10049 [inline]
>   bpf_check+0xd634/0x150d0 kernel/bpf/verifier.c:13759
>   bpf_prog_load kernel/bpf/syscall.c:2301 [inline]
>   __sys_bpf+0x11181/0x126e0 kernel/bpf/syscall.c:4587
>   __do_sys_bpf kernel/bpf/syscall.c:4691 [inline]
>   __se_sys_bpf kernel/bpf/syscall.c:4689 [inline]
>   __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4689
>   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>   do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
>   entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> Reported-by: syzbot+f3e749d4c662818ae439@syzkaller.appspotmail.com
> Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>

Acked-by: Yonghong Song <yhs@fb.com>