params: avoid a core dump with a null pointer and a get string call

Previous a get string (UTF8 or octet) params call would memcpy(2) from a NULL
pointer if the OSSL_PARAM didn't have its data field set.  This change makes
the operation fail rather than core dump and it returns to param size (if set).

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/11474)

diff --git a/crypto/params.c b/crypto/params.c
index 5d1fc6a6f2d1ea4290d172d593a7b7ab8bd17196..64d53c50e3a12d3263a3f07a548b42bb48fddb78 100644 (file)
--- a/crypto/params.c
+++ b/crypto/params.c
@@ -778,6 +778,8 @@ static int get_string_internal(const OSSL_PARAM *p, void **val, size_t max_len,
 
     if (sz == 0)
         return 1;
+    if (p->data == NULL)
+        return 0;
 
     if (*val == NULL) {
         char *const q = OPENSSL_malloc(sz);