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author | Andreas Schneider <asn@cryptomilk.org> | 2019-12-10 18:28:03 +0100 |
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committer | Andreas Schneider <asn@cryptomilk.org> | 2019-12-20 14:35:04 +0100 |
commit | 5317ebf0fcf927e45a4c7a8c322357179dd87f2f (patch) | |
tree | 4f6ee597c28e276f89a669c93d91125529964947 /src | |
parent | 08f4469e21981185eaf9da5d6f84eec9e845b124 (diff) | |
download | libssh-5317ebf0fcf927e45a4c7a8c322357179dd87f2f.tar.gz libssh-5317ebf0fcf927e45a4c7a8c322357179dd87f2f.tar.xz libssh-5317ebf0fcf927e45a4c7a8c322357179dd87f2f.zip |
misc: Add ssh_tmpname()
Signed-Off-By: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Diffstat (limited to 'src')
-rw-r--r-- | src/misc.c | 51 |
1 files changed, 51 insertions, 0 deletions
@@ -1735,4 +1735,55 @@ int ssh_newline_vis(const char *string, char *buf, size_t buf_len) return out - buf; } +/** + * @internal + * + * @brief Replaces the last 6 characters of a string from 'X' to 6 random hexdigits. + * + * @param[in] template Any input string with last 6 characters as 'X'. + * @returns -1 as error when the last 6 characters of the input to be replaced are not 'X' + * 0 otherwise. + */ +int ssh_tmpname(char *template) +{ + char *tmp = NULL; + size_t i = 0; + + if (template == NULL) { + goto err; + } + + tmp = template + strlen(template) - 6; + if (tmp < template) { + goto err; + } + + for (i = 0; i < 6; i++) { + if (tmp[i] != 'X') { + SSH_LOG(SSH_LOG_WARNING, + "Invalid input. Last six characters of the input must be \'X\'"); + goto err; + } + } + + srand(time(NULL)); + + for (i = 0; i < 6; ++i) { +#ifdef _WIN32 + /* in win32 MAX_RAND is 32767, thus we can not shift that far, + * otherwise the last three chars are 0 */ + int hexdigit = (rand() >> (i * 2)) & 0x1f; +#else + int hexdigit = (rand() >> (i * 5)) & 0x1f; +#endif + tmp[i] = hexdigit > 9 ? hexdigit + 'a' - 10 : hexdigit + '0'; + } + + return 0; + +err: + errno = EINVAL; + return -1; +} + /** @} */ |