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b1dbd3071d
Thanks to Nathanael A. Hoyle for the report! Some of these may have been exploitable due to pointer arithmetic before reads / writes. Just bail out if we can't allocate.
140 lines
3.9 KiB
C
140 lines
3.9 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <assert.h>
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#include <stdint.h>
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#include <inttypes.h>
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#include <arpa/inet.h>
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#include <pcre.h>
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#include <zlib.h>
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#define MAX_LINE 2048
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/******************************
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* this regular expression has the following capture groups in it (in order):
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* - ip
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* - path
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* - query
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* - user agent
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******************************/
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#define RE "(?:[0-9.]+,\\ )*([0-9.]+)"\
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"[^\"]+"\
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"\"GET\\s([^\\s?]+)\\?([^\\s]+)\\s[^\"]+\""\
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"\\s([^\\s]+)[^\"]+"\
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"\"[^\"]+\""\
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"[^\"]+"\
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"\"([^\"]+)\""
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#define GROUP_IP 1
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#define GROUP_PATH 2
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#define GROUP_QUERY 3
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#define GROUP_CODE 4
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#define GROUP_UA 5
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int main(int argc, char** argv)
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{
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/* compile the pattern */
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const char* error;
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int error_offset;
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pcre *re = pcre_compile(RE, 0, &error, &error_offset, NULL);
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if (re == NULL) {
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fprintf(
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stderr,
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"character %d: failed to compile regex: %s\n",
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error_offset,
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error
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);
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return 1;
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}
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/* study it to speed it up */
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pcre_extra *extra = pcre_study(re, 0, &error);
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/* allocate enough space for the capturing groups */
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int group_count;
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pcre_fullinfo(re, extra, PCRE_INFO_CAPTURECOUNT, &group_count);
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int match_vector_size = (group_count + 1) * 3;
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int *matches = malloc(sizeof(int) * match_vector_size);
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if (matches == NULL) {
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fprintf(stderr, "Couldn't allocate memory for regex groups!\n");
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return 1;
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}
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/* iterate through the input */
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char input_line[MAX_LINE];
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while (fgets(input_line, MAX_LINE, stdin)) {
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int length = strlen(input_line);
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/* run the regular expression against the line */
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int match_result = pcre_exec(
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re,
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extra,
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input_line,
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length,
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0,
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0,
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matches,
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match_vector_size
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);
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/* bail out if the line didn't match */
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if (match_result < 0) {
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continue;
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}
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/* iterate through the groups */
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/* NOTE: the crc function uses int32_t instead of uint32_t
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* and has the funky (2^31 - crc) bit of math for backwards
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* compatibility with the old python code. fix this when
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* such compatibility is no longer necessary. */
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uint32_t address = 0;
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int32_t crc;
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uint64_t unique_id;
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for (int i = 1; i < match_result; i++) {
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int start_position = matches[i * 2];
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int end_position = matches[i * 2 + 1];
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int substr_length = end_position - start_position;
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switch (i) {
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case GROUP_UA:
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crc = crc32(0L, Z_NULL, 0);
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crc = crc32(crc, (unsigned char*)input_line + start_position,
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substr_length);
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unique_id = (((uint64_t)address << 32) & 0xffffffff00000000) |
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(2147483648 - crc);
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fprintf(stdout, "%" PRIu64, unique_id);
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break;
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case GROUP_IP:
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/* parse and store the ip so we can use it in GROUP_UA
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* to calculate the unique id */
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input_line[end_position] = 0;
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address = inet_addr(input_line + start_position);
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/* fall through so it gets written out as well */
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case GROUP_PATH:
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case GROUP_CODE:
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case GROUP_QUERY:
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/* write them out verbatim */
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(void)fwrite(
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input_line + start_position,
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sizeof(char),
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substr_length,
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stdout
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);
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break;
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}
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/* tab-delimit the data */
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fputc('\t', stdout);
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}
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fputc('\n', stdout);
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}
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return 0;
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}
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