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Fixes to memory management in the elliptic curve code.

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There was an error-handling path testing the wrong variable; an
inappropriate call to ec_point_free in decodepoint() (in fact, that
function always gets passed a pointer to an ec_point structure that's
not a dynamically allocated block at all or not in its own right, so
we should have just cleared its contents without freeing the structure
itself); a missing return on an error path which would have caused the
same structure to be freed a second time; and two missing freebn in
ecdsa_sign.

Patch due to Tim Kosse.
This commit is contained in:
Simon Tatham 2014-12-20 17:07:17 +00:00
parent d23c0972cd
commit 0acc74d711
1 changed files with 9 additions and 2 deletions
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11
sshecc.c
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@ -628,7 +628,7 @@ static struct ec_point *ecp_double(const struct ec_point *a, const int aminus3)
}
XmZ2 = modsub(a->x, Z2, a->curve->p);
freebn(Z2);
if (!XpZ2) {
if (!XmZ2) {
freebn(S);
freebn(XpZ2);
return NULL;
@ -1434,7 +1434,10 @@ static int decodepoint(char *p, int length, struct ec_point *point)
/* Verify the point is on the curve */
if (!ec_point_verify(point)) {
ec_point_free(point);
freebn(point->x);
point->x = NULL;
freebn(point->y);
point->y = NULL;
return 0;
}
@ -1714,6 +1717,7 @@ static void *ecdsa_openssh_createkey(unsigned char **blob, int *len)
/* Private key doesn't make the public key on the given curve */
ecdsa_freekey(ec);
ec_point_free(publicKey);
return NULL;
}
ec_point_free(publicKey);
@ -1947,6 +1951,9 @@ static unsigned char *ecdsa_sign(void *key, char *data, int datalen,
for (i = slen; i--;)
*p++ = bignum_byte(s, i);
freebn(r);
freebn(s);
return buf;
}