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Code Issues Releases Wiki Activity

Simplify tr_ssha1_matches logic

Browse source 
Gets rid of needless heap memory allocations and copying. Convert SHA1 hash
to hex in-place.

Fixes: #141
This commit is contained in:
Mike Gelfand 2017-01-09 14:15:07 +03:00
parent 15625de3c7
commit 3375b22b23
2 changed files with 28 additions and 30 deletions
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41
libtransmission/crypto-utils.c
View file

@ -132,6 +132,8 @@ tr_ssha1 (const char * plain_text)
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"./";
assert (plain_text != NULL);
size_t i;
unsigned char salt[saltval_len];
uint8_t sha[SHA_DIGEST_LENGTH];
@ -154,34 +156,27 @@ bool
tr_ssha1_matches (const char * ssha1,
const char * plain_text)
{
char * salt;
size_t saltlen;
char * my_ssha1;
uint8_t buf[SHA_DIGEST_LENGTH];
bool result;
const size_t sourcelen = strlen (ssha1);
assert (ssha1 != NULL);
assert (plain_text != NULL);
const size_t brace_len = 1;
const size_t brace_and_hash_len = brace_len + 2 * SHA_DIGEST_LENGTH;
const size_t source_len = strlen (ssha1);
if (source_len < brace_and_hash_len || ssha1[0] != '{')
return false;
/* extract the salt */
if (sourcelen < 2 * SHA_DIGEST_LENGTH - 1)
return false;
saltlen = sourcelen - 2 * SHA_DIGEST_LENGTH - 1;
salt = tr_malloc (saltlen);
memcpy (salt, ssha1 + 2 * SHA_DIGEST_LENGTH + 1, saltlen);
const char * const salt = ssha1 + brace_and_hash_len;
const size_t salt_len = source_len - brace_and_hash_len;
uint8_t buf[SHA_DIGEST_LENGTH * 2 + 1];
/* hash pass + salt */
my_ssha1 = tr_malloc (2 * SHA_DIGEST_LENGTH + saltlen + 2);
tr_sha1 (buf, plain_text, (int) strlen (plain_text), salt, (int) saltlen, NULL);
tr_sha1_to_hex (&my_ssha1[1], buf);
memcpy (my_ssha1 + 1 + 2 * SHA_DIGEST_LENGTH, salt, saltlen);
my_ssha1[1 + 2 * SHA_DIGEST_LENGTH + saltlen] = '\0';
my_ssha1[0] = '{';
tr_sha1 (buf, plain_text, (int) strlen (plain_text), salt, (int) salt_len, NULL);
tr_sha1_to_hex ((char *) buf, buf);
result = strcmp (ssha1, my_ssha1) == 0;
tr_free (my_ssha1);
tr_free (salt);
return result;
return strncmp (ssha1 + brace_len, (const char *) buf, SHA_DIGEST_LENGTH * 2) == 0;
}
/***

17
libtransmission/utils.c
View file

@ -635,16 +635,19 @@ tr_binary_to_hex (const void * input,
{
static const char hex[] = "0123456789abcdef";
const uint8_t * input_octets = input;
size_t i;
for (i = 0; i < byte_length; ++i)
{
const unsigned int val = *input_octets++;
*output++ = hex[val >> 4];
*output++ = hex[val & 0xf];
}
/* go from back to front to allow for in-place conversion */
input_octets += byte_length;
output += byte_length * 2;
*output = '\0';
while (byte_length-- > 0)
{
const unsigned int val = *(--input_octets);
*(--output) = hex[val & 0xf];
*(--output) = hex[val >> 4];
}
}
void