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