r18214@catbus: nickm | 2008-02-19 17:07:55 -0500

Backport to 0.1.2.x: Add some checks in torgzip.c to make sure we never overflow size_t there.  Also make sure we do not realloc(list,0) in container.c.


svn:r13588

ChangeLog

@@ -19,6 +19,7 @@ Changes in versino 0.1.2.20 - 2008-??-??
       conditions.
     - We were leaking a file descriptor if Tor started with a zero-length
       cached-descriptors file. Patch by freddy77.
+    - Detect size overflow in zlib code.
 
 
 Changes in version 0.1.2.19 - 2008-01-17

src/common/container.c

@@ -65,6 +65,8 @@ smartlist_set_capacity(smartlist_t *sl, int n)
 {
   if (n < sl->num_used)
     n = sl->num_used;
+  if (n < 1)
+    n = 1;
   if (sl->capacity != n) {
     sl->capacity = n;
     sl->list = tor_realloc(sl->list, sizeof(void*)*sl->capacity);

src/common/torgzip.c

@@ -70,7 +70,7 @@ tor_gzip_compress(char **out, size_t *out_len,
                   compress_method_t method)
 {
   struct z_stream_s *stream = NULL;
-  size_t out_size;
+  size_t out_size, old_size;
   off_t offset;
 
   tor_assert(out);
@@ -118,7 +118,12 @@ tor_gzip_compress(char **out, size_t *out_len,
           break;
       case Z_BUF_ERROR:
         offset = stream->next_out - ((unsigned char*)*out);
+        old_size = out_size;
         out_size *= 2;
+        if (out_size < old_size) {
+          log_warn(LD_GENERAL, "Size overflow in compression.");
+          goto err;
+        }
         *out = tor_realloc(*out, out_size);
         stream->next_out = (unsigned char*)(*out + offset);
         if (out_size - offset > UINT_MAX) {
@@ -173,7 +178,7 @@ tor_gzip_uncompress(char **out, size_t *out_len,
                     int protocol_warn_level)
 {
   struct z_stream_s *stream = NULL;
-  size_t out_size;
+  size_t out_size, old_size;
   off_t offset;
   int r;
 
@@ -240,7 +245,12 @@ tor_gzip_uncompress(char **out, size_t *out_len,
           goto err;
         }
         offset = stream->next_out - (unsigned char*)*out;
+        old_size = out_size;
         out_size *= 2;
+        if (out_size < old_size) {
+          log_warn(LD_GENERAL, "Size overflow in compression.");
+          goto err;
+        }
         *out = tor_realloc(*out, out_size);
         stream->next_out = (unsigned char*)(*out + offset);
         if (out_size - offset > UINT_MAX) {