archival/libarchive/unsafe_prefix.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   4  */
   5 #include "libbb.h"
   6 #include "bb_archive.h"
   7
   8 const char* FAST_FUNC strip_unsafe_prefix(const char *str)
   9 {
  10         const char *cp = str;
  11         while (1) {
  12                 char *cp2;
  13                 if (*cp == '/') {
  14                         cp++;
  15                         continue;
  16                 }
  17                 if (is_prefixed_with(cp, "/../"+1)) {
  18                         cp += 3;
  19                         continue;
  20                 }
  21                 cp2 = strstr(cp, "/../");
  22                 if (!cp2)
  23                         break;
  24                 cp = cp2 + 4;
  25         }
  26         if (cp != str) {
  27                 static smallint warned = 0;
  28                 if (!warned) {
  29                         warned = 1;
  30                         bb_error_msg("removing leading '%.*s' from member names",
  31                                 (int)(cp - str), str);
  32                 }
  33         }
  34         return cp;
  35 }