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recommend_pkg.c (2170B)

      1 /* Copyright (c) 2001-2004, Roger Dingledine.
      2 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
      3 * Copyright (c) 2007-2021, The Tor Project, Inc. */
      4 /* See LICENSE for licensing information */
      5 
      6 /**
      7 * \file recommend_pkg.c
      8 * \brief Code related to the recommended-packages subsystem.
      9 *
     10 * Currently unused.
     11 **/
     12 
     13 #include "core/or/or.h"
     14 #include "feature/dirauth/recommend_pkg.h"
     15 
     16 /** Return true iff <b>line</b> is a valid RecommendedPackages line.
     17 */
     18 /*
     19  The grammar is:
     20 
     21    "package" SP PACKAGENAME SP VERSION SP URL SP DIGESTS NL
     22 
     23      PACKAGENAME = NONSPACE
     24      VERSION = NONSPACE
     25      URL = NONSPACE
     26      DIGESTS = DIGEST | DIGESTS SP DIGEST
     27      DIGEST = DIGESTTYPE "=" DIGESTVAL
     28 
     29      NONSPACE = one or more non-space printing characters
     30 
     31      DIGESTVAL = DIGESTTYPE = one or more non-=, non-" " characters.
     32 
     33      SP = " "
     34      NL = a newline
     35 
     36 */
     37 int
     38 validate_recommended_package_line(const char *line)
     39 {
     40  const char *cp = line;
     41 
     42 #define WORD()                                  \
     43  do {                                          \
     44    if (*cp == ' ')                             \
     45      return 0;                                 \
     46    cp = strchr(cp, ' ');                       \
     47    if (!cp)                                    \
     48      return 0;                                 \
     49  } while (0)
     50 
     51  WORD(); /* skip packagename */
     52  ++cp;
     53  WORD(); /* skip version */
     54  ++cp;
     55  WORD(); /* Skip URL */
     56  ++cp;
     57 
     58  /* Skip digesttype=digestval + */
     59  int n_entries = 0;
     60  while (1) {
     61    const char *start_of_word = cp;
     62    const char *end_of_word = strchr(cp, ' ');
     63    if (! end_of_word)
     64      end_of_word = cp + strlen(cp);
     65 
     66    if (start_of_word == end_of_word)
     67      return 0;
     68 
     69    const char *eq = memchr(start_of_word, '=', end_of_word - start_of_word);
     70 
     71    if (!eq)
     72      return 0;
     73    if (eq == start_of_word)
     74      return 0;
     75    if (eq == end_of_word - 1)
     76      return 0;
     77    if (memchr(eq+1, '=', end_of_word - (eq+1)))
     78      return 0;
     79 
     80    ++n_entries;
     81    if (0 == *end_of_word)
     82      break;
     83 
     84    cp = end_of_word + 1;
     85  }
     86 
     87  /* If we reach this point, we have at least 1 entry. */
     88  tor_assert(n_entries > 0);
     89  return 1;
     90 }