agent: Fix the condition to detect leading 0x00 problem.

* agent/sexp-secret.c (fixup_when_ecc_private_key): Use curve name
to identify the issue.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2020-06-08 10:55:16 +09:00
parent 47c1c329ed
commit e2e5736842
1 changed files with 16 additions and 5 deletions

View File

@ -29,6 +29,7 @@ gpg_error_t
fixup_when_ecc_private_key (unsigned char *buf, size_t *buflen_p)
{
const unsigned char *s;
char curve_name[256];
size_t n;
size_t buflen = *buflen_p;
@ -55,7 +56,18 @@ fixup_when_ecc_private_key (unsigned char *buf, size_t *buflen_p)
n = snext (&s);
if (!n)
return gpg_error (GPG_ERR_INV_SEXP);
if (n == 1 && *s == 'd')
if (n == 5 && !memcmp (s, "curve", 5))
{
s += n;
n = snext (&s);
if (!n || n >= sizeof curve_name)
return gpg_error (GPG_ERR_INV_SEXP);
memcpy (curve_name, s, n);
curve_name[n] = 0;
s += n;
}
else if (n == 1 && *s == 'd')
{
unsigned char *s0;
size_t n0;
@ -67,10 +79,9 @@ fixup_when_ecc_private_key (unsigned char *buf, size_t *buflen_p)
if (!n)
return gpg_error (GPG_ERR_INV_SEXP);
else if ((n & 1) && !*s)
/* Detect wrongly added 0x00. */
/* For all existing curves in libgcrypt-1.9 (so far), the
size of private part should be even. */
else if (!*s /* Leading 0x00 added at the front for classic curve */
&& strcmp (curve_name, "Ed25519")
&& strcmp (curve_name, "X448"))
{
size_t numsize;