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experiment: Fix for signature R+S in OpenPGP R part.

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This fix also allows having only OpenPGP R part,
and OpenPGP S part == NULL.

--

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2021-12-14 17:59:06 +09:00
parent a461eae58d
commit aa4b138f4d
2 changed files with 14 additions and 7 deletions
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3
g10/parse-packet.c
View File

@ -2378,6 +2378,9 @@ parse_signature (IOBUF inp, int pkttype, unsigned long pktlen,
} }
if (!sig->data[i]) if (!sig->data[i])
rc = GPG_ERR_INV_PACKET; rc = GPG_ERR_INV_PACKET;
if (!pktlen && sig->pubkey_algo == PUBKEY_ALGO_EDDSA)
/* Allow the R part only. */
break;
} }
} }

18
g10/pkglue.c
View File

@ -252,12 +252,13 @@ pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
{ {
gcry_mpi_t r = data[0]; gcry_mpi_t r = data[0];
gcry_mpi_t s = data[1]; gcry_mpi_t s = data[1];
unsigned int nbits;
const unsigned char *p;
if (openpgp_oid_is_ed25519 (pkey[0])) if (openpgp_oid_is_ed25519 (pkey[0]))
{ {
size_t rlen, slen, n; /* (bytes) */ size_t rlen, slen, n; /* (bytes) */
char buf[64]; char buf[64];
unsigned int nbits;
unsigned int neededfixedlen = 256 / 8; unsigned int neededfixedlen = 256 / 8;
log_assert (neededfixedlen <= sizeof buf); log_assert (neededfixedlen <= sizeof buf);
@ -292,8 +293,6 @@ pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
else if (rlen < neededfixedlen else if (rlen < neededfixedlen
&& gcry_mpi_get_flag (r, GCRYMPI_FLAG_OPAQUE)) && gcry_mpi_get_flag (r, GCRYMPI_FLAG_OPAQUE))
{ {
const unsigned char *p;
p = gcry_mpi_get_opaque (r, &nbits); p = gcry_mpi_get_opaque (r, &nbits);
n = (nbits+7)/8; n = (nbits+7)/8;
memcpy (buf + (neededfixedlen - n), p, n); memcpy (buf + (neededfixedlen - n), p, n);
@ -312,8 +311,6 @@ pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
else if (slen < neededfixedlen else if (slen < neededfixedlen
&& gcry_mpi_get_flag (s, GCRYMPI_FLAG_OPAQUE)) && gcry_mpi_get_flag (s, GCRYMPI_FLAG_OPAQUE))
{ {
const unsigned char *p;
p = gcry_mpi_get_opaque (s, &nbits); p = gcry_mpi_get_opaque (s, &nbits);
n = (nbits+7)/8; n = (nbits+7)/8;
memcpy (buf + (neededfixedlen - n), p, n); memcpy (buf + (neededfixedlen - n), p, n);
@ -322,8 +319,15 @@ pk_verify (pubkey_algo_t pkalgo, gcry_mpi_t hash,
} }
} }
} }
else if (!gcry_mpi_cmp_ui (s, 0)) /*
/* When data[1] == MPI(0), parse the signature into R and S parts. */ * When data[1] is NULL or [0], parse the signature into R and S
* parts.
*/
else if (!s
|| (gcry_mpi_get_flag (s, GCRYMPI_FLAG_OPAQUE)
&& ((p = gcry_mpi_get_opaque (s, &nbits)) == NULL
|| nbits == 0
|| ((nbits+7)/8 == 1 && p[0] == 0))))
openpgp_ecc_parse_signature (pkalgo, r, &r, &s); openpgp_ecc_parse_signature (pkalgo, r, &r, &s);
else else
rc = 0; rc = 0;