Handle allocation failures in C code gracefully

Thanks to Nathanael A. Hoyle for the report! Some of these may have
been exploitable due to pointer arithmetic before reads / writes.
Just bail out if we can't allocate.

r2/r2/lib/c/filters.c

@@ -54,6 +54,10 @@ filters_uwebsafe(PyObject * self, PyObject *args)
   len = PyUnicode_GetSize(com);
 
   buffer = (Py_UNICODE*)malloc(6*len*sizeof(Py_UNICODE));
+  if (buffer == NULL) {
+    return PyErr_NoMemory();
+  }
+
   for(ic = 0, ib = 0; ic < len; ic++, ib++) {
     c = input_buffer[ic];
     if (c == '&') {
@@ -108,6 +112,10 @@ filters_uwebsafe_json(PyObject * self, PyObject *args)
   len = PyUnicode_GetSize(com);
 
   buffer = (Py_UNICODE*)malloc(6*len*sizeof(Py_UNICODE));
+  if (buffer == NULL) {
+    return PyErr_NoMemory();
+  }
+
   for(ic = 0, ib = 0; ic < len; ic++, ib++) {
     c = input_buffer[ic];
     if (c == '&') {
@@ -153,6 +161,10 @@ filters_websafe(PyObject * self, PyObject *args)
     return NULL;
   len = strlen(input_buffer);
   buffer = (char*)malloc(6*len);
+  if (buffer == NULL) {
+    return PyErr_NoMemory();
+  }
+
   for(ic = 0, ib = 0; ic <= len; ic++, ib++) {
     c = input_buffer[ic];
     if (c == '&') {
@@ -231,6 +243,9 @@ filters_uspace_compress(PyObject * self, PyObject *args) {
   input_buffer = PyUnicode_AS_UNICODE(com);
   len = PyUnicode_GetSize(com);
   buffer = (Py_UNICODE*)malloc(len * sizeof(Py_UNICODE));
+  if (buffer == NULL) {
+    return PyErr_NoMemory();
+  }
 
   /* ic -> input buffer index, ib -> output buffer */
   for(ic = 0, ib = 0; ic <= len; ic++) {
@@ -295,6 +310,11 @@ static PyMethodDef FilterMethods[] = {
 
 Py_UNICODE *to_unicode(const char *c, int len) {
   Py_UNICODE *x = (Py_UNICODE *)malloc((len+1) * sizeof(Py_UNICODE));
+  if (x == NULL) {
+    PyErr_NoMemory();
+    return NULL;
+  }
+
   int i;
   for(i = 0; i < len; i++) {
     x[i] = (Py_UNICODE)c[i];

scripts/traffic/decrypt_userinfo.c

@@ -68,12 +68,24 @@ int main(int argc, char** argv)
 
         /* base 64 decode and decrypt the ciphertext */
         BIO* bio = BIO_new_mem_buf(ciphertext, b64_size);
+        if (bio == NULL) {
+            fprintf(stderr, "Failed to allocate buffer for b64 ciphertext\n");
+            return 1;
+        }
 
         BIO* b64 = BIO_new(BIO_f_base64());
+        if (b64 == NULL) {
+            fprintf(stderr, "Failed to allocate base64 filter\n");
+            return 1;
+        }
         BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
         bio = BIO_push(b64, bio);
 
         BIO* aes = BIO_new(BIO_f_cipher());
+        if (aes == NULL) {
+            fprintf(stderr, "Failed to allocate AES cipher\n");
+            return 1;
+        }
         BIO_set_cipher(
             aes,
             cipher,

scripts/traffic/parse.c

@@ -57,6 +57,10 @@ int main(int argc, char** argv)
     pcre_fullinfo(re, extra, PCRE_INFO_CAPTURECOUNT, &group_count);
     int match_vector_size = (group_count + 1) * 3;
     int *matches = malloc(sizeof(int) * match_vector_size);
+    if (matches == NULL) {
+        fprintf(stderr, "Couldn't allocate memory for regex groups!\n");
+        return 1;
+    }
 
     /* iterate through the input */
     char input_line[MAX_LINE];