strtoofft: reduce integer overflow risks globally

... make sure we bail out on overflows.

Reported-by: Brian Carpenter
Closes #1758

1 files changed, 18 insertions, 15 deletions

diff --git a/lib/ftp.c b/lib/ftp.c
index 6e86e5386..481b14a88 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -2260,11 +2260,13 @@ static CURLcode ftp_state_size_resp(struct connectdata *conn,
 {
   CURLcode result = CURLE_OK;
   struct Curl_easy *data=conn->data;
-  curl_off_t filesize;
+  curl_off_t filesize = -1;
   char *buf = data->state.buffer;
 
   /* get the size from the ascii string: */
-  filesize = (ftpcode == 213)?curlx_strtoofft(buf+4, NULL, 0):-1;
+  if(ftpcode == 213)
+    /* ignores parsing errors, which will make the size remain unknown */
+    (void)curlx_strtoofft(buf+4, NULL, 0, &filesize);
 
   if(instate == FTP_SIZE) {
 #ifdef CURL_FTP_HTTPSTYLE_HEAD
@@ -2435,7 +2437,7 @@ static CURLcode ftp_state_get_resp(struct connectdata *conn,
         /* if we have nothing but digits: */
         if(bytes++) {
           /* get the number! */
-          size = curlx_strtoofft(bytes, NULL, 0);
+          (void)curlx_strtoofft(bytes, NULL, 0, &size);
         }
       }
     }
@@ -3466,31 +3468,32 @@ static CURLcode ftp_range(struct connectdata *conn)
 {
   curl_off_t from, to;
   char *ptr;
-  char *ptr2;
   struct Curl_easy *data = conn->data;
   struct ftp_conn *ftpc = &conn->proto.ftpc;
 
   if(data->state.use_range && data->state.range) {
-    from=curlx_strtoofft(data->state.range, &ptr, 0);
+    CURLofft from_t;
+    CURLofft to_t;
+    from_t = curlx_strtoofft(data->state.range, &ptr, 0, &from);
+    if(from_t == CURL_OFFT_FLOW)
+      return CURLE_RANGE_ERROR;
     while(*ptr && (ISSPACE(*ptr) || (*ptr=='-')))
       ptr++;
-    to=curlx_strtoofft(ptr, &ptr2, 0);
-    if(ptr == ptr2) {
-      /* we didn't get any digit */
-      to=-1;
-    }
-    if((-1 == to) && (from>=0)) {
+    to_t = curlx_strtoofft(ptr, NULL, 0, &to);
+    if(to_t == CURL_OFFT_FLOW)
+      return CURLE_RANGE_ERROR;
+    if((to_t == CURL_OFFT_INVAL) && !from_t) {
       /* X - */
       data->state.resume_from = from;
       DEBUGF(infof(conn->data, "FTP RANGE %" CURL_FORMAT_CURL_OFF_T
                    " to end of file\n", from));
     }
-    else if(from < 0) {
+    else if(!to_t && (from_t == CURL_OFFT_INVAL)) {
       /* -Y */
-      data->req.maxdownload = -from;
-      data->state.resume_from = from;
+      data->req.maxdownload = to;
+      data->state.resume_from = -to;
       DEBUGF(infof(conn->data, "FTP RANGE the last %" CURL_FORMAT_CURL_OFF_T
-                   " bytes\n", -from));
+                   " bytes\n", to));
     }
     else {
       /* X-Y */