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/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
#include "bb_archive.h"
int FAST_FUNC unsafe_symlink_target(const char *target)
{
const char *dot;
if (target[0] == '/') {
const char *var;
unsafe:
var = getenv("EXTRACT_UNSAFE_SYMLINKS");
if (var) {
if (LONE_CHAR(var, '1'))
return 0; /* pretend it's safe */
return 1; /* "UNSAFE!" */
}
bb_error_msg("skipping unsafe symlink to '%s' in archive,"
" set %s=1 to extract",
target,
"EXTRACT_UNSAFE_SYMLINKS"
);
/* Prevent further messages */
setenv("EXTRACT_UNSAFE_SYMLINKS", "0", 0);
return 1; /* "UNSAFE!" */
}
dot = target;
for (;;) {
dot = strchr(dot, '.');
if (!dot)
return 0; /* safe target */
/* Is it a path component starting with ".."? */
if ((dot[1] == '.')
&& (dot == target || dot[-1] == '/')
/* Is it exactly ".."? */
&& (dot[2] == '/' || dot[2] == '\0')
) {
goto unsafe;
}
/* NB: it can even be trailing ".", should only add 1 */
dot += 1;
}
}
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