Attachment 672371 Details for Bug 891577 – Upstream fix for CVE-2012-6090

[patch] Upstream fix for CVE-2012-6090

0002-SECURITY-Possible-buffer-overflows-when-expanding-fi.patch (text/plain), 3.55 KB, created by Petr Pisar on 2013-01-04 11:33:02 UTC

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Creator: Petr Pisar

Created: 2013-01-04 11:33:02 UTC

Size: 3.55 KB

patch

obsolete

>From b2c88972e7515ada025e97e7d3ce3e34f81cf33e Mon Sep 17 00:00:00 2001
>From: Jan Wielemaker <J.Wielemaker@cs.vu.nl>
>Date: Sun, 16 Dec 2012 17:29:37 +0100
>Subject: [PATCH] SECURITY: Possible buffer overflows when expanding
> file-names with long paths.  Affects expand_file_name/2.
>
>Can lead to crashes (DoS attacks) and possibly execution of arbitrary
>code if an attacker can control the names of the files searched for,
>e.g., if expand_file_name/2 is used in a directory to which an attacker
>can upload files for which he can control the name.
>---
> src/os/pl-glob.c | 46 ++++++++++++++++++++++++++++------------------
> 1 file changed, 28 insertions(+), 18 deletions(-)
>
>diff --git a/src/os/pl-glob.c b/src/os/pl-glob.c
>index 46ddf5b..0b1baeb 100644
>--- a/src/os/pl-glob.c
>+++ b/src/os/pl-glob.c
>@@ -424,6 +424,7 @@ expand(const char *pattern, GlobInfo info)
>   compiled_pattern cbuf;
>   char prefix[MAXPATHLEN];		/* before first pattern */
>   char patbuf[MAXPATHLEN];		/* pattern buffer */
>+  size_t prefix_len;
>   int end, dot;
> 
>   initBuffer(&info->files);
>@@ -442,20 +443,25 @@ expand(const char *pattern, GlobInfo info)
>       switch( (c=*s++) )
>       { case EOS:
> 	  if ( s > pat )		/* something left and expanded */
>-	  { un_escape(prefix, pat, s);
>+	  { size_t prefix_len;
>+
>+	    un_escape(prefix, pat, s);
>+	    prefix_len = strlen(prefix);
> 
> 	    end = info->end;
> 	    for( ; info->start < end; info->start++ )
> 	    { char path[MAXPATHLEN];
>-	      size_t plen;
>-
>-	      strcpy(path, expand_entry(info, info->start));
>-	      plen = strlen(path);
>-	      if ( prefix[0] && plen > 0 && path[plen-1] != '/' )
>-		path[plen++] = '/';
>-	      strcpy(&path[plen], prefix);
>-	      if ( end == 1 || AccessFile(path, ACCESS_EXIST) )
>-		add_path(path, info);
>+	      const char *entry = expand_entry(info, info->start);
>+	      size_t plen = strlen(entry);
>+
>+	      if ( plen+prefix_len+2 <= MAXPATHLEN )
>+	      { strcpy(path, entry);
>+		if ( prefix[0] && plen > 0 && path[plen-1] != '/' )
>+		  path[plen++] = '/';
>+		strcpy(&path[plen], prefix);
>+		if ( end == 1 || AccessFile(path, ACCESS_EXIST) )
>+		  add_path(path, info);
>+	      }
> 	    }
> 	  }
> 	  succeed;
>@@ -490,8 +496,9 @@ expand(const char *pattern, GlobInfo info)
> */
>     un_escape(prefix, pat, head);
>     un_escape(patbuf, head, tail);
>+    prefix_len = strlen(prefix);
> 
>-    if ( !compilePattern(patbuf, &cbuf) )		/* syntax error */
>+    if ( !compilePattern(patbuf, &cbuf) )	/* syntax error */
>       fail;
>     dot = (patbuf[0] == '.');			/* do dots as well */
> 
>@@ -503,12 +510,16 @@ expand(const char *pattern, GlobInfo info)
>       char path[MAXPATHLEN];
>       char tmp[MAXPATHLEN];
>       const char *current = expand_entry(info, info->start);
>+      size_t clen = strlen(current);
>+
>+      if ( clen+prefix_len+1 > sizeof(path) )
>+	continue;
> 
>       strcpy(path, current);
>-      strcat(path, prefix);
>+      strcpy(&path[clen], prefix);
> 
>       if ( (d=opendir(path[0] ? OsPath(path, tmp) : ".")) )
>-      { size_t plen = strlen(path);
>+      { size_t plen = clen+prefix_len;
> 
> 	if ( plen > 0 && path[plen-1] != '/' )
> 	  path[plen++] = '/';
>@@ -522,12 +533,11 @@ expand(const char *pattern, GlobInfo info)
> 	       matchPattern(e->d_name, &cbuf) )
> 	  { char newp[MAXPATHLEN];
> 
>-	    strcpy(newp, path);
>-	    strcpy(&newp[plen], e->d_name);
>-/*	    if ( !tail[0] || ExistsDirectory(newp) )
>-	    Saves memory, but involves one more file-access
>-*/
>+	    if ( plen+strlen(e->d_name)+1 < sizeof(newp) )
>+	    { strcpy(newp, path);
>+	      strcpy(&newp[plen], e->d_name);
> 	      add_path(newp, info);
>+	    }
> 	  }
> 	}
> 	closedir(d);
>-- 
>1.7.11.7
>

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Attachments on bug 891577: 672370 | 672371 | 672401 | 672402