commit cad15b9f92812ea4cdec6b65b7e2a83bdc007eb3
author Daniel Stenberg <daniel@haxx.se> Mon Apr 27 12:21:17 2020 +0200
committer Daniel Stenberg <daniel@haxx.se> Mon Apr 27 16:25:59 2020 +0200
tree 62a0740e28a5ec9a1b1b6e3dbb0098fe841b7e23
parent e2b1ccb99beb2c68417c3757aaa7d5d6ba83215f

nss: check for PK11_CreateDigestContext() returning NULL

... to avoid crashes!

Reported-by: Hao Wu
Fixes #5302
Closes #5303

lib/vtls/nss.c

diff --git a/lib/vtls/nss.c b/lib/vtls/nss.c
index 3a65a66..16ec409 100644
--- a/lib/vtls/nss.c
+++ b/lib/vtls/nss.c
@@ -2374,6 +2374,9 @@
   PK11Context *MD5pw = PK11_CreateDigestContext(SEC_OID_MD5);
   unsigned int MD5out;
 
+  if(!MD5pw)
+    return CURLE_NOT_BUILT_IN;
+
   PK11_DigestOp(MD5pw, tmp, curlx_uztoui(tmplen));
   PK11_DigestFinal(MD5pw, md5sum, &MD5out, curlx_uztoui(md5len));
   PK11_DestroyContext(MD5pw, PR_TRUE);
@@ -2389,6 +2392,9 @@
   PK11Context *SHA256pw = PK11_CreateDigestContext(SEC_OID_SHA256);
   unsigned int SHA256out;
 
+  if(!SHA256pw)
+    return CURLE_NOT_BUILT_IN;
+
   PK11_DigestOp(SHA256pw, tmp, curlx_uztoui(tmplen));
   PK11_DigestFinal(SHA256pw, sha256sum, &SHA256out, curlx_uztoui(sha256len));
   PK11_DestroyContext(SHA256pw, PR_TRUE);