src/feature/dirauth/recommend_pkg.c

   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 }