tar garbles symlinks

[David Vrabel]

Package: busybox
Version: 0.45
Severity: Normal

When creating a tar archive containing directories containing multiple
symlinks the symlinks become garbled
eg
    adduser -> /bin/tinylogin
    ls -> /bin/busybox
becomes (when untarred)
    adduser -> /bin/tinylogin
    ls -> /bin/busboxin
(note reproducing this behavior seems to require many symlinks in a
directory)

The problem lies in writeTarHeader().  readlink() fills a character
buffer with the link name.  This buffer is not null terminated =>
header.linkname is not filled correctly.

Suggested fix:
--- tar.c.old   Wed Jun 21 16:19:33 2000
+++ tar.c       Tue Aug 15 09:22:53 2000
@@ -824,13 +824,15 @@
 
        /* WARNING/NOTICE: I break Hard Links */
        if (S_ISLNK(statbuf->st_mode)) {
-               char buffer[BUFSIZ];
+               char buffer[sizeof(header.linkname)];
+               int len;
                header.typeflag  = SYMTYPE;
-               if ( readlink(fileName, buffer, sizeof(buffer) - 1) < 0)
{
+               if ( (len=readlink(fileName, buffer, sizeof(buffer) -
1)) < 0) {                        errorMsg("Error reading symlink '%s':
%s\n", header.name, strerror(errno));
                        return ( FALSE);
                }
-               strncpy(header.linkname, buffer,
sizeof(header.linkname));
+               strncpy(header.linkname, buffer,
sizeof(header.linkname));
+               header.linkname[len]='\0';
        } else if (S_ISDIR(statbuf->st_mode)) {
                header.typeflag  = DIRTYPE;
                strncat(header.name, "/",
sizeof(header.name));


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Received: (at 1024-done) by bugs.lineo.com; 21 Aug 2000 23:09:17 +0000