commit 6eeef115a9096b954dd6d873978abbb28055d301
author Neels Hofmeyr <neels@hofmeyr.de> Wed Dec 20 23:14:45 2017 +0100
committer Neels Hofmeyr <neels@hofmeyr.de> Wed Dec 20 23:31:45 2017 +0100
tree b8087e3385f1365b128004039fa0f985635b0bcb
parent 66d6d760aab222c91bec5134c228ffc13f463235

hnbap,rua,ranap decode: fix segfault on decode error

Looking at hnbap_decode_hnbregisterrequesties(), I noticed a segfault if
decoding the HNB Register Request PDU fails, which is due to an unchecked
return value in code generated by asn1tostruct.py.

Add return value and NULL pointer checks and hence fix null dereference on
erratic PDUs across HNBAP, RUA and RANAP protocols. Similar checks exist in
other places, this one was simply missing.

Since the result of asn1tostruct.py is not committed, here is an example diff
of the resulting change, of which there are 128 instances in total:

@@ -304,7 +329,12 @@
     memset(hnbRegisterRequestIEs, 0, sizeof(HNBRegisterRequestIEs_t));
     HNBAP_DEBUG("Decoding message HNBRegisterRequestIEs (%s:%d)\n", __FILE__, __LINE__);

-    ANY_to_type_aper(any_p, &asn_DEF_HNBRegisterRequest, (void**)&hNBRegisterRequest_p);
+    tempDecoded = ANY_to_type_aper(any_p, &asn_DEF_HNBRegisterRequest, (void**)&hNBRegisterRequest_p);
+
+    if (tempDecoded < 0 || hNBRegisterRequest_p == NULL) {
+        HNBAP_DEBUG("Decoding of message HNBRegisterRequestIEs failed\n");
+        return -1;
+    }

     for (i = 0; i < hNBRegisterRequest_p->hnbRegisterRequest_ies.list.count; i++) {
         IE_t *ie_p;

Change-Id: I6cb9cc9a88d22f03befa43f0968a874476fa079d

asn1/utils/asn1tostruct.py

diff --git a/asn1/utils/asn1tostruct.py b/asn1/utils/asn1tostruct.py
index 8364c27..5586e40 100755
--- a/asn1/utils/asn1tostruct.py
+++ b/asn1/utils/asn1tostruct.py
@@ -311,7 +311,12 @@
         f.write("    memset(%s, 0, sizeof(%s_t));\n" % (lowerFirstCamelWord(re.sub('-', '_', key)), prefix + re.sub('-', '_', key)))
 
     f.write("    %s_DEBUG(\"Decoding message %s (%%s:%%d)\\n\", __FILE__, __LINE__);\n\n" % (fileprefix.upper(), prefix + re.sub('-', '_', keyName)))
-    f.write("    ANY_to_type_aper(any_p, &asn_DEF_%s, (void**)&%s_p);\n\n" % (asn1cStruct, asn1cStructfirstlower))
+    f.write("    tempDecoded = ANY_to_type_aper(any_p, &asn_DEF_%s, (void**)&%s_p);\n\n" % (asn1cStruct, asn1cStructfirstlower))
+    f.write("    if (tempDecoded < 0 || %s_p == NULL) {\n" % (asn1cStructfirstlower))
+    f.write("        %s_DEBUG(\"Decoding of message %s failed\\n\");\n" % (fileprefix.upper(), prefix + re.sub('-', '_', keyName)))
+    f.write("        return -1;\n")
+    f.write("    }\n\n")
+
     f.write("    for (i = 0; i < %s_p->%slist.count; i++) {\n" % (asn1cStructfirstlower, iesaccess))
     f.write("        %sIE_t *ie_p;\n" % (prefix))
     f.write("        ie_p = %s_p->%slist.array[i];\n" % (asn1cStructfirstlower, iesaccess))