diff --git a/src/detect-csum.c b/src/detect-csum.c
index 8ad4bb60b8..9ef4b230e3 100644
--- a/src/detect-csum.c
+++ b/src/detect-csum.c
@@ -177,7 +177,8 @@ void DetectCsumRegister (void)
  * \param cd  Pointer to the DetectCsumData structure that holds the keyword
  *            value sent as argument
  *
- * \retval 1 if the keyvalue has been parsed successfully, and 0 otherwise
+ * \retval 1 the keyvalue has been parsed successfully
+ * \retval 0 error
  */
 static int DetectCsumParseArg(const char *key, DetectCsumData *cd)
 {
@@ -186,8 +187,12 @@ static int DetectCsumParseArg(const char *key, DetectCsumData *cd)
     if (key[0] == '\"' && key[strlen(key) - 1] == '\"') {
         str = SCStrdup(key + 1);
         str[strlen(key) - 2] = '\0';
-    } else
+    } else {
         str = SCStrdup(key);
+    }
+    if (str == NULL) {
+        goto error;
+    }
 
     if (strcasecmp(str, DETECT_CSUM_VALID) == 0 ||
         strcasecmp(str, DETECT_CSUM_INVALID) == 0) {
@@ -196,7 +201,9 @@ static int DetectCsumParseArg(const char *key, DetectCsumData *cd)
         return 1;
     }
 
-    SCFree(str);
+error:
+    if (str != NULL)
+        SCFree(str);
     return 0;
 }
 
diff --git a/src/detect-rev.c b/src/detect-rev.c
index 1e0df2ab89..1e16857dd5 100644
--- a/src/detect-rev.c
+++ b/src/detect-rev.c
@@ -46,13 +46,17 @@ static int DetectRevSetup (DetectEngineCtx *de_ctx, Signature *s, char *rawstr)
     /* strip "'s */
     if (rawstr[0] == '\"' && rawstr[strlen(rawstr)-1] == '\"') {
         str = SCStrdup(rawstr+1);
+        if (str == NULL)
+            return -1;
+
         str[strlen(rawstr)-2] = '\0';
         dubbed = 1;
     }
 
     s->rev = (uint8_t)atoi(str);
 
-    if (dubbed) SCFree(str);
+    if (dubbed)
+        SCFree(str);
     return 0;
 }
 
diff --git a/src/detect-sid.c b/src/detect-sid.c
index 9cf62b39f2..ed25869502 100644
--- a/src/detect-sid.c
+++ b/src/detect-sid.c
@@ -46,13 +46,17 @@ static int DetectSidSetup (DetectEngineCtx *de_ctx, Signature *s, char *sidstr)
     /* strip "'s */
     if (sidstr[0] == '\"' && sidstr[strlen(sidstr)-1] == '\"') {
         str = SCStrdup(sidstr+1);
+        if (str == NULL)
+            return -1;
+
         str[strlen(sidstr)-2] = '\0';
         dubbed = 1;
     }
 
     s->id = (uint32_t)atoi(str);
 
-    if (dubbed) SCFree(str);
+    if (dubbed)
+        SCFree(str);
     return 0;
 }