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factotum: replace custom hex parsing code with dec16() avoding timing side channels

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This commit is contained in:
cinap_lenrek 2018-01-01 21:14:39 +01:00
parent 5cf5f6e9ac
commit f7b0cc7a64
2 changed files with 5 additions and 54 deletions
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31
sys/src/cmd/auth/factotum/p9sk1.c
View file

@ -506,33 +506,6 @@ p9skclose(Fsstate *fss)
free(s); free(s);
} }
static int
unhex(char c)
{
if('0' <= c && c <= '9')
return c-'0';
if('a' <= c && c <= 'f')
return c-'a'+10;
if('A' <= c && c <= 'F')
return c-'A'+10;
abort();
return -1;
}
static int
hexparse(char *hex, uchar *dat, int ndat)
{
int i;
if(strlen(hex) != 2*ndat)
return -1;
if(hex[strspn(hex, "0123456789abcdefABCDEF")] != '\0')
return -1;
for(i=0; i<ndat; i++)
dat[i] = (unhex(hex[2*i])<<4)|unhex(hex[2*i+1]);
return 0;
}
static int static int
p9skaddkey(Key *k, int before) p9skaddkey(Key *k, int before)
{ {
@ -547,13 +520,13 @@ p9skaddkey(Key *k, int before)
akey = emalloc(sizeof(Authkey)); akey = emalloc(sizeof(Authkey));
if(s = _strfindattr(k->privattr, "!hex")){ if(s = _strfindattr(k->privattr, "!hex")){
if(k->proto == &dp9ik){ if(k->proto == &dp9ik){
if(hexparse(s, akey->aes, AESKEYLEN) < 0){ if(dec16(akey->aes, AESKEYLEN, s, strlen(s)) != AESKEYLEN){
free(akey); free(akey);
werrstr("malformed key data"); werrstr("malformed key data");
return -1; return -1;
} }
} else { } else {
if(hexparse(s, (uchar*)akey->des, DESKEYLEN) < 0){ if(dec16((uchar*)akey->des, DESKEYLEN, s, strlen(s)) != DESKEYLEN){
free(akey); free(akey);
werrstr("malformed key data"); werrstr("malformed key data");
return -1; return -1;

28
sys/src/cmd/auth/factotum/wpapsk.c
View file

@ -35,35 +35,13 @@ struct State
uchar resp[PTKlen]; uchar resp[PTKlen];
}; };
static int
hextob(char *s, char **sp, uchar *b, int n)
{
int r;
n <<= 1;
for(r = 0; r < n && *s; s++){
*b <<= 4;
if(*s >= '0' && *s <= '9')
*b |= (*s - '0');
else if(*s >= 'a' && *s <= 'f')
*b |= 10+(*s - 'a');
else if(*s >= 'A' && *s <= 'F')
*b |= 10+(*s - 'A');
else break;
if((++r & 1) == 0)
b++;
}
if(sp != nil)
*sp = s;
return r >> 1;
}
static void static void
pass2pmk(char *pass, char *ssid, uchar pmk[PMKlen]) pass2pmk(char *pass, char *ssid, uchar pmk[PMKlen])
{ {
if(hextob(pass, nil, pmk, PMKlen) == PMKlen) int npass = strlen(pass);
if(npass == 2*PMKlen && dec16(pmk, PMKlen, pass, npass) == PMKlen)
return; return;
pbkdf2_x((uchar*)pass, strlen(pass), (uchar*)ssid, strlen(ssid), 4096, pmk, PMKlen, hmac_sha1, SHA1dlen); pbkdf2_x((uchar*)pass, npass, (uchar*)ssid, strlen(ssid), 4096, pmk, PMKlen, hmac_sha1, SHA1dlen);
} }
static void static void