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* decrypt.c (prepare_decryption): Hack to detected already 

unpkcsedone keys.
This commit is contained in:
Werner Koch 2002-08-09 21:01:03 +00:00
parent beb0fef1ee
commit dc8f3ee42c
2 changed files with 37 additions and 26 deletions
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3
sm/ChangeLog
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@ -1,5 +1,8 @@
2002-08-09 Werner Koch <wk@gnupg.org>
* decrypt.c (prepare_decryption): Hack to detected already
unpkcsedone keys.
* gpgsm.c (emergency_cleanup): New.
(main): Initialize the signal handler.

60
sm/decrypt.c
View File

@ -73,35 +73,43 @@ prepare_decryption (const char *hexkeygrip, KsbaConstSexp enc_val,
log_printhex ("pkcs1 encoded session key:", seskey, seskeylen);
n=0;
if (n + 7 > seskeylen )
if (seskeylen == 24)
{
rc = seterr (Invalid_Session_Key);
goto leave;
/* Smells like a 3-des key. This might happen because a SC has
already done the unpacking. fixme! */
}
else
{
if (n + 7 > seskeylen )
{
rc = seterr (Invalid_Session_Key);
goto leave;
}
/* FIXME: Actually the leading zero is required but due to the way
we encode the output in libgcrypt as an MPI we are not able to
encode that leading zero. However, when using a Smartcard we are
doing it the rightway and therefore we have to skip the zero. This
should be fixed in gpg-agent of course. */
if (!seskey[n])
n++;
if (seskey[n] != 2 ) /* wrong block type version */
{
rc = seterr (Invalid_Session_Key);
goto leave;
}
for (n++; n < seskeylen && seskey[n]; n++) /* skip the random bytes */
;
n++; /* and the zero byte */
if (n >= seskeylen )
{
rc = seterr (Invalid_Session_Key);
goto leave;
}
}
/* FIXME: Actually the leading zero is required but due to the way
we encode the output in libgcrypt as an MPI we are not able to
encode that leading zero. However, when using a Smartcard we are
doing it the rightway and therefore we have to skip the zero. This
should be fixed in gpg-agent of course. */
if (!seskey[n])
n++;
if (seskey[n] != 2 ) /* wrong block type version */
{
rc = seterr (Invalid_Session_Key);
goto leave;
}
for (n++; n < seskeylen && seskey[n]; n++) /* skip the random bytes */
;
n++; /* and the zero byte */
if (n >= seskeylen )
{
rc = seterr (Invalid_Session_Key);
goto leave;
}
if (DBG_CRYPTO)
log_printhex ("session key:", seskey+n, seskeylen-n);