cangrepp

Some cryptographic attacks
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fmpzio.c (3022B)

      1 #include "fmpzio.h"
      2 
      3 #define BASE_ALLOC 1024
      4 #define LINE_SIZE_MAX 8192
      5 
      6 int
      7 read_next_fmpz(fmpz_t res)
      8 {
      9   char buffer[LINE_SIZE_MAX];
     10   size_t i;
     11 
     12   int next_char = getchar();
     13   while (next_char == '\n' || next_char == ' ')
     14     next_char = getchar();
     15 
     16   if (next_char == EOF)
     17     return -1;
     18 
     19   buffer[0] = next_char;
     20   i = 1;
     21   while (i < LINE_SIZE_MAX - 1) {
     22     next_char = getchar();
     23     if (next_char == EOF || next_char == '\n' || next_char == ' ')
     24       break;
     25 
     26     buffer[i] = (char)next_char;
     27 
     28     i++;
     29   }
     30   buffer[i] = '\0';
     31 
     32   return fmpz_set_str(res, buffer, 10);
     33 }
     34 
     35 int
     36 read_next_hex_fmpz(fmpz_t res)
     37 {
     38   char buffer[LINE_SIZE_MAX];
     39   size_t i;
     40 
     41   int next_char = getchar();
     42   while (next_char == '\n' || next_char == ' ')
     43     next_char = getchar();
     44 
     45   if (next_char == EOF)
     46     return -1;
     47 
     48   buffer[0] = next_char;
     49   i = 1;
     50   while (i < LINE_SIZE_MAX - 1) {
     51     next_char = getchar();
     52     if (next_char == EOF || next_char == '\n' || next_char == ' ')
     53       break;
     54 
     55     buffer[i] = (char)next_char;
     56 
     57     i++;
     58   }
     59   buffer[i] = '\0';
     60 
     61   return fmpz_set_str(res, buffer, 16);
     62 }
     63 
     64 static char *
     65 read_all_stdin(const size_t base_alloc)
     66 {
     67   size_t rsize, cread = 0, current_size = base_alloc;
     68   char *buffer = malloc(base_alloc * sizeof(*buffer));
     69 
     70   if (buffer == NULL)
     71     return NULL;
     72 
     73   rsize = fread(buffer, sizeof(*buffer), base_alloc, stdin);
     74 
     75   while (rsize + cread == current_size) {
     76     cread = current_size;
     77     current_size <<= 1;
     78     buffer = realloc(buffer, current_size * sizeof(*buffer));
     79 
     80     if (buffer == NULL)
     81       return NULL;
     82 
     83     rsize = fread(&buffer[cread], sizeof(*buffer), cread, stdin);
     84   }
     85 
     86   buffer[rsize + cread] = '\0';
     87 
     88   return buffer;
     89 }
     90 
     91 static inline char *
     92 whitespace_sep(char **s)
     93 {
     94   char *orig = *s;
     95 
     96   if (**s == '\0') {
     97     return NULL;
     98   }
     99 
    100   while (**s != '\0') {
    101     if (**s == ' ' || **s == '\t' || **s == '\n') {
    102       **s = '\0';
    103       (*s)++;
    104       break;
    105     }
    106     (*s)++;
    107   }
    108 
    109   return orig;
    110 }
    111 
    112 slong
    113 read_hex_lines(fmpz **v)
    114 {
    115   assert(v != NULL);
    116 
    117   slong i;
    118   char *r = read_all_stdin(BASE_ALLOC);
    119 
    120   if (r == NULL) {
    121     err(EXIT_FAILURE, "reading entire stdin failed");
    122   }
    123 
    124   char *s = r;
    125   slong ntokens = 0, tokens_alloc = BASE_ALLOC;
    126   char **tokens = malloc(tokens_alloc * sizeof(*tokens));
    127 
    128   while ((tokens[ntokens] = whitespace_sep(&s)) != NULL) {
    129     ntokens++;
    130 
    131     if (ntokens == tokens_alloc) {
    132       tokens_alloc <<= 1;
    133       tokens = realloc(tokens, tokens_alloc * sizeof(*tokens));
    134 
    135       if (tokens == NULL) {
    136         err(EXIT_FAILURE, "reallocating tokens failed");
    137       }
    138     }
    139   }
    140 
    141   if (ntokens == 0) {
    142     err(EXIT_FAILURE, "nothing to read for read_hex_lines");
    143   }
    144 
    145   *v = _fmpz_vec_init(ntokens);
    146 
    147   if (*v == NULL) {
    148     err(EXIT_FAILURE, "creating vector in read_hex_lines failed");
    149   }
    150 
    151   for (i = 0; i < ntokens; i++) {
    152     if (fmpz_set_str(&(*v)[i], tokens[i], 16) != 0) {
    153       errx(EXIT_FAILURE, "could not interpret \"%s\" as hex integer",
    154            tokens[i]);
    155     }
    156   }
    157 
    158   free(r);
    159   free(tokens);
    160 
    161   return ntokens;
    162 }