checksrc: ban unsafe functions

The list of unsafe functions currently consists of sprintf, vsprintf,
strcat, strncat and gets.

Subsequently, some existing code needed updating to avoid warnings on
this.

4 files changed, 27 insertions, 123 deletions

diff --git a/lib/checksrc.pl b/lib/checksrc.pl
index 9f5058ddb..f561492a7 100755
--- a/lib/checksrc.pl
+++ b/lib/checksrc.pl
@@ -6,7 +6,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 2011 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -153,6 +153,12 @@ sub scanfile {
             checkwarn($line, length($1)+1, $file, $l, "missing space after close paren");
         }
 
+        # scan for use of banned functions
+        if($l =~ /^(.*\W)(sprintf|vsprintf|strcat|strncat|gets)\s*\(/) {
+            checkwarn($line, length($1), $file, $l,
+                      "use of $2 is banned");
+        }
+
         # check for open brace first on line but not first column
         # only alert if previous line ended with a close paren and wasn't a cpp
         # line
diff --git a/lib/ftp.c b/lib/ftp.c
index dc9fc4816..d9b854783 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -3978,16 +3978,11 @@ static CURLcode wc_statemach(struct connectdata *conn)
     /* filelist has at least one file, lets get first one */
     struct ftp_conn *ftpc = &conn->proto.ftpc;
     struct curl_fileinfo *finfo = wildcard->filelist->head->ptr;
-    char *tmp_path = malloc(strlen(conn->data->state.path) +
-                      strlen(finfo->filename) + 1);
-    if(!tmp_path) {
+
+    char *tmp_path = aprintf("%s%s", wildcard->path, finfo->filename);
+    if(!tmp_path)
       return CURLE_OUT_OF_MEMORY;
-    }
 
-    tmp_path[0] = 0;
-    /* make full path to matched file */
-    strcat(tmp_path, wildcard->path);
-    strcat(tmp_path, finfo->filename);
     /* switch default "state.pathbuffer" and tmp_path, good to see
        ftp_parse_url_path function to understand this trick */
     Curl_safefree(conn->data->state.pathbuffer);
@@ -4124,13 +4119,13 @@ CURLcode Curl_ftpsendf(struct connectdata *conn,
 
   va_list ap;
   va_start(ap, fmt);
-  vsnprintf(s, SBUF_SIZE-3, fmt, ap);
+  write_len = vsnprintf(s, SBUF_SIZE-3, fmt, ap);
   va_end(ap);
 
-  strcat(s, "\r\n"); /* append a trailing CRLF */
+  strcpy(&s[write_len], "\r\n"); /* append a trailing CRLF */
+  write_len +=2;
 
   bytes_written=0;
-  write_len = strlen(s);
 
   res = Curl_convert_to_network(conn->data, s, write_len);
   /* Curl_convert_to_network calls failf if unsuccessful */
diff --git a/lib/http_digest.c b/lib/http_digest.c
index f9f20d487..43513966b 100644
--- a/lib/http_digest.c
+++ b/lib/http_digest.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -287,6 +287,7 @@ CURLcode Curl_output_digest(struct connectdata *conn,
   struct timeval now;
 
   char **allocuserpwd;
+  size_t userlen;
   const char *userp;
   const char *passwdp;
   struct auth *authp;
@@ -533,10 +534,11 @@ CURLcode Curl_output_digest(struct connectdata *conn,
   }
 
   /* append CRLF + zero (3 bytes) to the userpwd header */
-  tmp = realloc(*allocuserpwd, strlen(*allocuserpwd) + 3);
+  userlen = strlen(*allocuserpwd);
+  tmp = realloc(*allocuserpwd, userlen + 3);
   if(!tmp)
     return CURLE_OUT_OF_MEMORY;
-  strcat(tmp, "\r\n");
+  strcpy(&tmp[userlen], "\r\n"); /* append the data */
   *allocuserpwd = tmp;
 
   return CURLE_OK;
diff --git a/lib/mprintf.c b/lib/mprintf.c
index b5b81536a..2ec4a7534 100644
--- a/lib/mprintf.c
+++ b/lib/mprintf.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1999 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1999 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -203,101 +203,6 @@ static int dprintf_IsQualifierNoDollar(char c)
   }
 }
 
-#ifdef DPRINTF_DEBUG2
-static void dprintf_Pass1Report(va_stack_t *vto, int max)
-{
-  int i;
-  char buffer[256];
-  int bit;
-  int flags;
-
-  for(i=0; i<max; i++) {
-    char *type;
-    switch(vto[i].type) {
-    case FORMAT_UNKNOWN:
-      type = "unknown";
-      break;
-    case FORMAT_STRING:
-      type ="string";
-      break;
-    case FORMAT_PTR:
-      type ="pointer";
-      break;
-    case FORMAT_INT:
-      type = "int";
-      break;
-    case FORMAT_INTPTR:
-      type = "intptr";
-      break;
-    case FORMAT_LONG:
-      type = "long";
-      break;
-    case FORMAT_LONGLONG:
-      type = "long long";
-      break;
-    case FORMAT_DOUBLE:
-      type = "double";
-      break;
-    case FORMAT_LONGDOUBLE:
-      type = "long double";
-      break;
-    }
-
-
-    buffer[0]=0;
-
-    for(bit=0; bit<31; bit++) {
-      flags = vto[i].flags & (1<<bit);
-
-      if(flags & FLAGS_SPACE)
-        strcat(buffer, "space ");
-      else if(flags & FLAGS_SHOWSIGN)
-        strcat(buffer, "plus ");
-      else if(flags & FLAGS_LEFT)
-        strcat(buffer, "left ");
-      else if(flags & FLAGS_ALT)
-        strcat(buffer, "alt ");
-      else if(flags & FLAGS_SHORT)
-        strcat(buffer, "short ");
-      else if(flags & FLAGS_LONG)
-        strcat(buffer, "long ");
-      else if(flags & FLAGS_LONGLONG)
-        strcat(buffer, "longlong ");
-      else if(flags & FLAGS_LONGDOUBLE)
-        strcat(buffer, "longdouble ");
-      else if(flags & FLAGS_PAD_NIL)
-        strcat(buffer, "padnil ");
-      else if(flags & FLAGS_UNSIGNED)
-        strcat(buffer, "unsigned ");
-      else if(flags & FLAGS_OCTAL)
-        strcat(buffer, "octal ");
-      else if(flags & FLAGS_HEX)
-        strcat(buffer, "hex ");
-      else if(flags & FLAGS_UPPER)
-        strcat(buffer, "upper ");
-      else if(flags & FLAGS_WIDTH)
-        strcat(buffer, "width ");
-      else if(flags & FLAGS_WIDTHPARAM)
-        strcat(buffer, "widthparam ");
-      else if(flags & FLAGS_PREC)
-        strcat(buffer, "precision ");
-      else if(flags & FLAGS_PRECPARAM)
-        strcat(buffer, "precparam ");
-      else if(flags & FLAGS_CHAR)
-        strcat(buffer, "char ");
-      else if(flags & FLAGS_FLOATE)
-        strcat(buffer, "floate ");
-      else if(flags & FLAGS_FLOATG)
-        strcat(buffer, "floatg ");
-    }
-    printf("REPORT: %d. %s [%s]\n", i, type, buffer);
-
-  }
-
-
-}
-#endif
-
 /******************************************************************
  *
  * Pass 1:
@@ -537,10 +442,6 @@ static long dprintf_Pass1(const char *format, va_stack_t *vto, char **endpos,
     }
   }
 
-#ifdef DPRINTF_DEBUG2
-  dprintf_Pass1Report(vto, max_param);
-#endif
-
   /* Read the arg list parameters into our data list */
   for(i=0; i<max_param; i++) {
     if((i + 1 < max_param) && (vto[i + 1].type == FORMAT_WIDTH)) {
@@ -919,7 +820,7 @@ static int dprintf_formatf(
     case FORMAT_DOUBLE:
       {
         char formatbuf[32]="%";
-        char *fptr;
+        char *fptr = &formatbuf[1];
         size_t left = sizeof(formatbuf)-strlen(formatbuf);
         int len;
 
@@ -936,15 +837,15 @@ static int dprintf_formatf(
           prec = (long)vto[p->precision].data.num.as_signed;
 
         if(p->flags & FLAGS_LEFT)
-          strcat(formatbuf, "-");
+          *fptr++ = '-';
         if(p->flags & FLAGS_SHOWSIGN)
-          strcat(formatbuf, "+");
+          *fptr++ = '+';
         if(p->flags & FLAGS_SPACE)
-          strcat(formatbuf, " ");
+          *fptr++ = ' ';
         if(p->flags & FLAGS_ALT)
-          strcat(formatbuf, "#");
+          *fptr++ = '#';
 
-        fptr=&formatbuf[strlen(formatbuf)];
+        *fptr = 0;
 
         if(width >= 0) {
           /* RECURSIVE USAGE */
@@ -969,8 +870,8 @@ static int dprintf_formatf(
 
         *fptr = 0; /* and a final zero termination */
 
-        /* NOTE NOTE NOTE!! Not all sprintf() implementations returns number
-           of output characters */
+        /* NOTE NOTE NOTE!! Not all sprintf implementations return number of
+           output characters */
         (sprintf)(work, formatbuf, p->data.dnum);
 
         for(fptr=work; *fptr; fptr++)