Minor security fix: mod_imagemagick used popen to run covert, change it to use pipe...

[synfig.git] / synfig-core / trunk / src / modules / mod_imagemagick / trgt_imagemagick.cpp

diff --git a/synfig-core/trunk/src/modules/mod_imagemagick/trgt_imagemagick.cpp b/synfig-core/trunk/src/modules/mod_imagemagick/trgt_imagemagick.cpp
index 88dd95a..bfd8f59 100644 (file)
--- a/synfig-core/trunk/src/modules/mod_imagemagick/trgt_imagemagick.cpp
+++ b/synfig-core/trunk/src/modules/mod_imagemagick/trgt_imagemagick.cpp
@@ -36,6 +36,9 @@
 #include <ETL/stringf>
 #include "trgt_imagemagick.h"
 #include <stdio.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
 #include <algorithm>
 #include <functional>
 #include <ETL/clock>
@@ -61,6 +64,7 @@ SYNFIG_TARGET_SET_CVS_ID(imagemagick_trgt,"$Id$");
 
 imagemagick_trgt::imagemagick_trgt(const char *Filename)
 {
+       pid=-1;
        file=NULL;
        filename=Filename;
        multi_image=false;
@@ -70,8 +74,11 @@ imagemagick_trgt::imagemagick_trgt(const char *Filename)
 
 imagemagick_trgt::~imagemagick_trgt()
 {
-       if(file)
-               pclose(file);
+       if(file){
+               fclose(file);
+               int status;
+               waitpid(pid,&status,0);
+       }
        file=NULL;
        delete [] buffer;
        delete [] color_buffer;
@@ -110,7 +117,9 @@ imagemagick_trgt::end_frame()
        {
                fputc(0,file);
                fflush(file);
-               pclose(file);
+               fclose(file);
+               int status;
+               waitpid(pid,&status,0);
        }
        file=NULL;
        imagecount++;
@@ -119,7 +128,8 @@ imagemagick_trgt::end_frame()
 bool
 imagemagick_trgt::start_frame(synfig::ProgressCallback *cb)
 {
-       string command;
+       const char *msg=_("Unable to open pipe to imagemagick's convert utility");
+
        string newfilename;
 
        if (multi_image)
@@ -129,18 +139,55 @@ imagemagick_trgt::start_frame(synfig::ProgressCallback *cb)
        else
                newfilename = filename;
 
-       command=strprintf("convert -depth 8 -size %dx%d rgb%s:-[0] -density %dx%d \"%s\"\n",
-                                         desc.get_w(), desc.get_h(),                                   // size
-                                         ((channels(pf) == 4) ? "a" : ""),                             // rgba or rgb?
-                                         round_to_int(desc.get_x_res()/39.3700787402), // density
-                                         round_to_int(desc.get_y_res()/39.3700787402),
-                                         newfilename.c_str());
-
-       file=popen(command.c_str(),POPEN_BINARY_WRITE_TYPE);
+       int p[2];
+  
+       if (pipe(p)) {
+               if(cb) cb->error(N_(msg));
+               else synfig::error(N_(msg));
+               return false;
+       };
+  
+       pid = fork();
+  
+       if (pid == -1) {
+               if(cb) cb->error(N_(msg));
+               else synfig::error(N_(msg));
+               return false;
+       }
+       
+       if (pid == 0){
+               // Child process
+               // Close pipeout, not needed
+               close(p[1]);
+               // Dup pipeout to stdin
+               if( dup2( p[0], STDIN_FILENO ) == -1 ){
+                       if(cb) cb->error(N_(msg));
+                       else synfig::error(N_(msg));
+                       return false;
+               }
+               // Close the unneeded pipeout
+               close(p[0]);
+               execlp("convert", "convert",
+                       "-depth", "8",
+                       "-size", strprintf("%dx%d", desc.get_w(), desc.get_h()).c_str(),
+                       ((channels(pf) == 4) ? "rgba:-[0]" : "rgb:-[0]"),
+                       "-density", strprintf("%dx%d", round_to_int(desc.get_x_res()/39.3700787402), round_to_int(desc.get_y_res()/39.3700787402)).c_str(),
+                       newfilename.c_str(),
+                       (const char *)NULL);
+               // We should never reach here unless the exec failed
+               if(cb) cb->error(N_(msg));
+               else synfig::error(N_(msg));
+               return false;
+       } else {
+               // Parent process
+               // Close pipein, not needed
+               close(p[0]);
+               // Save pipeout to file handle, will write to it later
+               file = fdopen(p[1], "wb");
+       }
 
        if(!file)
        {
-               const char *msg=_("Unable to open pipe to imagemagick's convert utility");
                if(cb)cb->error(N_(msg));
                else synfig::error(N_(msg));
                return false;