diff options
Diffstat (limited to 'libmisc/salt.c')
| -rw-r--r-- | libmisc/salt.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/libmisc/salt.c b/libmisc/salt.c index e0f278ee..c72447ea 100644 --- a/libmisc/salt.c +++ b/libmisc/salt.c @@ -9,7 +9,7 @@ #include <config.h> -#ident "$Id: salt.c 3489 2011-09-18 20:40:50Z nekral-guest $" +#ident "$Id$" #include <sys/time.h> #include <stdlib.h> @@ -23,7 +23,7 @@ static void seedRNG (void); static /*@observer@*/const char *gensalt (size_t salt_size); #ifdef USE_SHA_CRYPT -static size_t SHA_salt_size (void); +static long shadow_random (long min, long max); static /*@observer@*/const char *SHA_salt_rounds (/*@null@*/int *prefered_rounds); #endif /* USE_SHA_CRYPT */ @@ -81,17 +81,29 @@ static void seedRNG (void) #define MAGNUM(array,ch) (array)[0]=(array)[2]='$',(array)[1]=(ch),(array)[3]='\0' #ifdef USE_SHA_CRYPT +/* It is not clear what is the maximum value of random(). + * We assume 2^31-1.*/ +#define RANDOM_MAX 0x7FFFFFFF + /* - * Return the salt size. - * The size of the salt string is between 8 and 16 bytes for the SHA crypt - * methods. + * Return a random number between min and max (both included). + * + * It favors slightly the higher numbers. */ -static size_t SHA_salt_size (void) +static long shadow_random (long min, long max) { - double rand_size; + double drand; + long ret; seedRNG (); - rand_size = (double) 9.0 * random () / RAND_MAX; - return (size_t) (8 + rand_size); + drand = (double) (max - min + 1) * random () / RANDOM_MAX; + /* On systems were this is not random() range is lower, we favor + * higher numbers of salt. */ + ret = (long) (max + 1 - drand); + /* And we catch limits, and use the highest number */ + if ((ret < min) || (ret > max)) { + ret = max; + } + return ret; } /* Default number of rounds if not explicitly specified. */ @@ -112,7 +124,6 @@ static /*@observer@*/const char *SHA_salt_rounds (/*@null@*/int *prefered_rounds if (NULL == prefered_rounds) { long min_rounds = getdef_long ("SHA_CRYPT_MIN_ROUNDS", -1); long max_rounds = getdef_long ("SHA_CRYPT_MAX_ROUNDS", -1); - double rand_rounds; if ((-1 == min_rounds) && (-1 == max_rounds)) { return ""; @@ -130,10 +141,7 @@ static /*@observer@*/const char *SHA_salt_rounds (/*@null@*/int *prefered_rounds max_rounds = min_rounds; } - seedRNG (); - rand_rounds = (double) (max_rounds-min_rounds+1.0) * random (); - rand_rounds /= RAND_MAX; - rounds = min_rounds + rand_rounds; + rounds = shadow_random (min_rounds, max_rounds); } else if (0 == *prefered_rounds) { return ""; } else { @@ -226,11 +234,11 @@ static /*@observer@*/const char *gensalt (size_t salt_size) } else if (0 == strcmp (method, "SHA256")) { MAGNUM(result, '5'); strcat(result, SHA_salt_rounds((int *)arg)); - salt_len = SHA_salt_size(); + salt_len = (size_t) shadow_random (8, 16); } else if (0 == strcmp (method, "SHA512")) { MAGNUM(result, '6'); strcat(result, SHA_salt_rounds((int *)arg)); - salt_len = SHA_salt_size(); + salt_len = (size_t) shadow_random (8, 16); #endif /* USE_SHA_CRYPT */ } else if (0 != strcmp (method, "DES")) { fprintf (stderr, |