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Fix SSH-1 RSA key handling in Pageant.

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The auxiliary values (the two primes and the inverse of one mod the
other) were being read into the key structure wrongly, causing
crt_modpow() in sshrsa.c to give the wrong answers where straight
modpow would not have.

This must have been broken ever since I implemented the RSA CRT
optimisation in 2011. And nobody has noticed, which is a good sign for
the phasing out of SSH-1 :-) I only spotted it myself because I was
testing all the Pageant message types in the course of implementing
the new logging.
This commit is contained in:
Simon Tatham 2015-05-06 20:49:07 +01:00
parent bc4066e454
commit 5e2443ff1f
1 changed files with 6 additions and 2 deletions
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8
pageant.c
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@ -580,6 +580,10 @@ void *pageant_handle_msg(const void *msg, int msglen, int *outlen,
} }
p += n; p += n;
/* SSH-1 names p and q the other way round, i.e. we have
* the inverse of p mod q and not of q mod p. We swap the
* names, because our internal RSA wants iqmp. */
n = ssh1_read_bignum(p, msgend - p, &key->iqmp); /* p^-1 mod q */ n = ssh1_read_bignum(p, msgend - p, &key->iqmp); /* p^-1 mod q */
if (n < 0) { if (n < 0) {
freersakey(key); freersakey(key);
@ -589,7 +593,7 @@ void *pageant_handle_msg(const void *msg, int msglen, int *outlen,
} }
p += n; p += n;
n = ssh1_read_bignum(p, msgend - p, &key->p); /* p */ n = ssh1_read_bignum(p, msgend - p, &key->q); /* p */
if (n < 0) { if (n < 0) {
freersakey(key); freersakey(key);
sfree(key); sfree(key);
@ -598,7 +602,7 @@ void *pageant_handle_msg(const void *msg, int msglen, int *outlen,
} }
p += n; p += n;
n = ssh1_read_bignum(p, msgend - p, &key->q); /* q */ n = ssh1_read_bignum(p, msgend - p, &key->p); /* q */
if (n < 0) { if (n < 0) {
freersakey(key); freersakey(key);
sfree(key); sfree(key);