Re: [PATCH] selftests/net/ipsec: Fix Null pointer dereference in rtattr_pack()

On Tue, Jan 14, 2025 at 03:43:29PM +0800, liuye wrote:

Fix the following warning.

I think it is a bit more than a warning, I'd phrase this more like, even as it repeats the subject. Also, it would be nice to cite the tool that generates the warning.

Address Null pointer dereference in rtattr_pack.

Flagged by ??? as:

tools/testing/selftests/net/ipsec.c:230:25: warning: Possible null pointer
dereference: payload [nullPointer]
memcpy(RTA_DATA(attr), payload, size);
                       ^
tools/testing/selftests/net/ipsec.c:1618:54: note: Calling function 'rtattr_pack',
4th argument 'NULL' value is 0
if (rtattr_pack(&req.nh, sizeof(req), XFRMA_IF_ID, NULL, 0)) {
                                                   ^
tools/testing/selftests/net/ipsec.c:230:25: note: Null pointer dereference
memcpy(RTA_DATA(attr), payload, size);
                       ^

And I wonder if a fixes tag is appropriate, and if so this one:

70bfdf62e93a ("selftests/net/ipsec: Add test for xfrm_spdattr_type_t")

And, accordingly if this patch should be targeted at net:

[PATCH net] ...

Signed-off-by: liuye liuye@kylinos.cn

Please consider separating out your family and given name in hte signed-off-by line. Perhaps Lin Ye (apologies if that is incorrect).

The above not withstanding, the code change looks good to me. So feel free to include the following in a v2 with an updated patch description.

---

tools/testing/selftests/net/ipsec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/ipsec.c b/tools/testing/selftests/net/ipsec.c index be4a30a0d02a..725310ac26a9 100644 --- a/tools/testing/selftests/net/ipsec.c +++ b/tools/testing/selftests/net/ipsec.c @@ -227,7 +227,8 @@ static int rtattr_pack(struct nlmsghdr *nh, size_t req_sz, attr->rta_len = RTA_LENGTH(size); attr->rta_type = rta_type;

• memcpy(RTA_DATA(attr), payload, size);

• if (payload != NULL)

I think it would be more idiomatic to express this as:

if (payload)

• memcpy(RTA_DATA(attr), payload, size);
  

return 0; } -- 2.25.1