Mercurial > dropbear
comparison dbutil.c @ 817:a625f9e135a4
Constant time memcmp for the hmac and password crypt
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Thu, 03 Oct 2013 22:25:30 +0800 |
| parents | d63ef1e211ea |
| children | 4095b6d7c9fc |
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| 816:84e4259dae3e | 817:a625f9e135a4 |
|---|---|
| 882 return DROPBEAR_FAILURE; | 882 return DROPBEAR_FAILURE; |
| 883 } else { | 883 } else { |
| 884 return DROPBEAR_SUCCESS; | 884 return DROPBEAR_SUCCESS; |
| 885 } | 885 } |
| 886 } | 886 } |
| 887 | |
| 888 int constant_time_memcmp(const void* a, const void *b, size_t n) | |
| 889 { | |
| 890 const char *xa = a, *xb = b; | |
| 891 uint8_t c = 0; | |
| 892 size_t i; | |
| 893 for (i = 0; i < n; i++) | |
| 894 { | |
| 895 c |= (xa[i] ^ xb[i]); | |
| 896 } | |
| 897 return c; | |
| 898 } | |
| 899 |