Possible null dereference in cookie.c

[JMoerman]

I had to look for bugs in curl using Coverity for an assignment and encountered this in cookie.c:

curl/lib/cookie.c

Lines 875 to 878 in b898b4c

	if(!co->name)
	badcookie = TRUE;
	/* For Netscape file format cookies we check prefix on the name */
	if(strncasecompare("__Secure-", co->name, 9))

According to the first if statement co->name can be null and co->name is passed to strncasecompare (Curl_strncasecompare) which does not check for null and dereferences this parameter.

int Curl_strncasecompare(const char *first, const char *second, size_t max)
{
  while(*first && *second && max) {
...

Encountered when analyzing 9e8f28a, still present in b898b4c (which currently is the latest commit in master).

I don't think that it is a huge issue, but it doesn't seem to be a false positive and could potentially cause a crash.

[danielgustafsson]

Thanks for the report, it is indeed a low-risk NULL pointer deref case. I've opened PR #3821 to fix this.