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gpg: Accept Ed25519 private key in SOS which reserves leading zeros.

* g10/parse-packet.c (sos_read): Backport from 2.3.
(parse_key): Use sos_read for Ed25519 private key.

--

Note that we keep the code of sos_read as same as 2.3.  Even it is
set, the GCRYMPI_FLAG_USER2 flag is not used.

GnuPG-bug-id: 5120
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2021-12-07 15:37:55 +09:00
parent 4cf8bdb048
commit 14de7b1e59

View File

@ -188,6 +188,76 @@ mpi_read (iobuf_t inp, unsigned int *ret_nread, int secure)
}
/* Read an external representation of an SOS and return the opaque MPI
with GCRYMPI_FLAG_USER2. The external format is a 16-bit unsigned
value stored in network byte order giving information for the
following octets.
The caller must set *RET_NREAD to the maximum number of bytes to
read from the pipeline INP. This function sets *RET_NREAD to be
the number of bytes actually read from the pipeline.
If SECURE is true, the integer is stored in secure memory
(allocated using gcry_xmalloc_secure). */
static gcry_mpi_t
sos_read (iobuf_t inp, unsigned int *ret_nread, int secure)
{
int c, c1, c2, i;
unsigned int nmax = *ret_nread;
unsigned int nbits, nbytes;
size_t nread = 0;
gcry_mpi_t a = NULL;
byte *buf = NULL;
byte *p;
if (!nmax)
goto overflow;
if ((c = c1 = iobuf_get (inp)) == -1)
goto leave;
if (++nread == nmax)
goto overflow;
nbits = c << 8;
if ((c = c2 = iobuf_get (inp)) == -1)
goto leave;
++nread;
nbits |= c;
if (nbits > MAX_EXTERN_MPI_BITS)
{
log_error ("mpi too large (%u bits)\n", nbits);
goto leave;
}
nbytes = (nbits + 7) / 8;
buf = secure ? gcry_xmalloc_secure (nbytes) : gcry_xmalloc (nbytes);
p = buf;
for (i = 0; i < nbytes; i++)
{
if (nread == nmax)
goto overflow;
c = iobuf_get (inp);
if (c == -1)
goto leave;
p[i] = c;
nread ++;
}
a = gcry_mpi_set_opaque (NULL, buf, nbits);
gcry_mpi_set_flag (a, GCRYMPI_FLAG_USER2);
*ret_nread = nread;
return a;
overflow:
log_error ("mpi larger than indicated length (%u bits)\n", 8*nmax);
leave:
*ret_nread = nread;
gcry_free(buf);
return a;
}
/* Register STRING as a known critical notation name. */
void
register_known_notation (const char *string)
@ -2728,6 +2798,9 @@ parse_key (IOBUF inp, int pkttype, unsigned long pktlen,
goto leave;
}
n = pktlen;
if (algorithm == PUBKEY_ALGO_EDDSA)
pk->pkey[i] = sos_read (inp, &n, 0);
else
pk->pkey[i] = mpi_read (inp, &n, 0);
pktlen -= n;
if (list_mode)