diff options
| -rw-r--r-- | cipher/ecc-curves.c | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/cipher/ecc-curves.c b/cipher/ecc-curves.c index 26006d6c..900b668a 100644 --- a/cipher/ecc-curves.c +++ b/cipher/ecc-curves.c @@ -1200,13 +1200,18 @@ mpi_ec_setup_elliptic_curve (mpi_ec_t ec, int flags, if ((n+7)/8 != len) { - if ((n+7)/8 < len && ec->dialect == ECC_DIALECT_ED25519) + if (ec->dialect == ECC_DIALECT_ED25519) { /* * GnuPG (<= 2.2) or OpenPGP implementations with no * SOS support may remove zeros at the beginning. * Recover those zeros. */ + /* + * Also, GnuPG (<= 2.2) may add additional zero at + * the beginning, when private key is moved from + * OpenPGP to gpg-agent. Remove such a zero-prefix. + */ const unsigned char *buf; unsigned char *value; @@ -1214,13 +1219,26 @@ mpi_ec_setup_elliptic_curve (mpi_ec_t ec, int flags, if (!buf) return GPG_ERR_INV_OBJ; - value = xtrycalloc_secure (1, len); + value = xtrymalloc_secure (len); if (!value) return gpg_err_code_from_syserror (); - memset (value, 0, len - (n+7)/8); - memcpy (value + len - (n+7)/8, buf, (n+7)/8); - mpi_set_opaque (ec->d, value, len); + if ((n+7)/8 < len) + /* Recover zeros. */ + { + memset (value, 0, len - (n+7)/8); + memcpy (value + len - (n+7)/8, buf, (n+7)/8); + } + else if ((n+7)/8 == len + 1) + /* Remove a zero. */ + memcpy (value, buf+1, len); + else + { + xfree (value); + return GPG_ERR_INV_OBJ; + } + + mpi_set_opaque (ec->d, value, len*8); } else { |