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Validate newly created DSA keys more carefully. Don't want a structure

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half-filled with null pointers.

[originally from svn r9986]
This commit is contained in:
Simon Tatham 2013-08-04 19:33:49 +00:00
parent 4b1fcc8ba2
commit 76dc7c49a2
1 changed files with 22 additions and 8 deletions
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30
sshdss.c
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@ -82,6 +82,8 @@ static Bignum get160(char **data, int *datalen)
return b; return b;
} }
static void dss_freekey(void *key); /* forward reference */
static void *dss_newkey(char *data, int len) static void *dss_newkey(char *data, int len)
{ {
char *p; char *p;
@ -111,6 +113,13 @@ static void *dss_newkey(char *data, int len)
dss->y = getmp(&data, &len); dss->y = getmp(&data, &len);
dss->x = NULL; dss->x = NULL;
if (!dss->p || !dss->q || !dss->g || !dss->y ||
!bignum_cmp(dss->q, Zero) || !bignum_cmp(dss->p, Zero)) {
/* Invalid key. */
dss_freekey(dss);
return NULL;
}
return dss; return dss;
} }
@ -389,7 +398,13 @@ static void *dss_createkey(unsigned char *pub_blob, int pub_len,
Bignum ytest; Bignum ytest;
dss = dss_newkey((char *) pub_blob, pub_len); dss = dss_newkey((char *) pub_blob, pub_len);
if (!dss)
return NULL;
dss->x = getmp(&pb, &priv_len); dss->x = getmp(&pb, &priv_len);
if (!dss->x) {
dss_freekey(dss);
return NULL;
}
/* /*
* Check the obsolete hash in the old DSS key format. * Check the obsolete hash in the old DSS key format.
@ -435,14 +450,11 @@ static void *dss_openssh_createkey(unsigned char **blob, int *len)
dss->y = getmp(b, len); dss->y = getmp(b, len);
dss->x = getmp(b, len); dss->x = getmp(b, len);
if (!dss->p || !dss->q || !dss->g || !dss->y || !dss->x) { if (!dss->p || !dss->q || !dss->g || !dss->y || !dss->x ||
freebn(dss->p); !bignum_cmp(dss->q, Zero) || !bignum_cmp(dss->p, Zero)) {
freebn(dss->q); /* Invalid key. */
freebn(dss->g); dss_freekey(dss);
freebn(dss->y); return NULL;
freebn(dss->x);
sfree(dss);
return NULL;
} }
return dss; return dss;
@ -482,6 +494,8 @@ static int dss_pubkey_bits(void *blob, int len)
int ret; int ret;
dss = dss_newkey((char *) blob, len); dss = dss_newkey((char *) blob, len);
if (!dss)
return -1;
ret = bignum_bitcount(dss->p); ret = bignum_bitcount(dss->p);
dss_freekey(dss); dss_freekey(dss);