| Message ID | 1377169317-5959-4-git-send-email-jlee@suse.com (mailing list archive) |
|---|---|
| State | RFC, archived |
| Headers | show |
On Thu 2013-08-22 19:01:42, Lee, Chun-Yi wrote: > Due to RSA_I2OSP is not only used by signature verification path but also used > in signature generation path. So, separate the length checking of octet string > because it's not for generate 0x00 0x01 leading string when used in signature > generation. > > Reviewed-by: Jiri Kosina <jkosina@suse.cz> > Signed-off-by: Lee, Chun-Yi <jlee@suse.com> > +static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) > +{ > + unsigned x_size; > + unsigned X_size; > + u8 *X = NULL; Is this kernel code or entry into obfuscated C code contest? This is not funny. Pavel
? ??2013-08-25 ? 18:01 +0200?Pavel Machek ??? > On Thu 2013-08-22 19:01:42, Lee, Chun-Yi wrote: > > Due to RSA_I2OSP is not only used by signature verification path but also used > > in signature generation path. So, separate the length checking of octet string > > because it's not for generate 0x00 0x01 leading string when used in signature > > generation. > > > > Reviewed-by: Jiri Kosina <jkosina@suse.cz> > > Signed-off-by: Lee, Chun-Yi <jlee@suse.com> > > > +static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) > > +{ > > + unsigned x_size; > > + unsigned X_size; > > + u8 *X = NULL; > > Is this kernel code or entry into obfuscated C code contest? This is not funny. > > Pavel The small "x" is the input integer that will transfer to big "X" that is a octet sting. Sorry for I direct give variable name to match with spec, maybe I need use big_X or.... Do you have good suggest for the naming? Thanks a lot! Joey Lee -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi! > > > Due to RSA_I2OSP is not only used by signature verification path but also used > > > in signature generation path. So, separate the length checking of octet string > > > because it's not for generate 0x00 0x01 leading string when used in signature > > > generation. > > > > > > Reviewed-by: Jiri Kosina <jkosina@suse.cz> > > > Signed-off-by: Lee, Chun-Yi <jlee@suse.com> > > > > > +static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) > > > +{ > > > + unsigned x_size; > > > + unsigned X_size; > > > + u8 *X = NULL; > > > > Is this kernel code or entry into obfuscated C code contest? This is not funny. > > > The small "x" is the input integer that will transfer to big "X" that is > a octet sting. > > Sorry for I direct give variable name to match with spec, maybe I need > use big_X or.... Having variables that differ only in case is confusing. Actually RSA_I2OSP is not a good name for function, either. If it converts x into X, perhaps you can name one input and second output? > Do you have good suggest for the naming? Not really, sorry. Pavel
On Mon, 26 Aug 2013, Pavel Machek wrote: > > > > Due to RSA_I2OSP is not only used by signature verification path but also used > > > > in signature generation path. So, separate the length checking of octet string > > > > because it's not for generate 0x00 0x01 leading string when used in signature > > > > generation. > > > > > > > > Reviewed-by: Jiri Kosina <jkosina@suse.cz> > > > > Signed-off-by: Lee, Chun-Yi <jlee@suse.com> > > > > > > > +static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) > > > > +{ > > > > + unsigned x_size; > > > > + unsigned X_size; > > > > + u8 *X = NULL; > > > > > > Is this kernel code or entry into obfuscated C code contest? This is not funny. > > > > > The small "x" is the input integer that will transfer to big "X" that is > > a octet sting. > > > > Sorry for I direct give variable name to match with spec, maybe I need > > use big_X or.... > > Having variables that differ only in case is confusing. Actually > RSA_I2OSP is not a good name for function, either. > > If it converts x into X, perhaps you can name one input and second output? The variable naming is according to spec, and I believe it makes sense to keep it so, no matter how stupid the naming in the spec might be. Otherwise you have to do mental remapping when looking at the code and the spec at the same time, which is very inconvenient. Would a comment next to the variable declaration, that would point this fact out, be satisfactory for you?
diff --git a/crypto/asymmetric_keys/rsa.c b/crypto/asymmetric_keys/rsa.c index 6996ff7..c26ae77 100644 --- a/crypto/asymmetric_keys/rsa.c +++ b/crypto/asymmetric_keys/rsa.c @@ -121,12 +121,30 @@ static int RSAVP1(const struct public_key *key, MPI s, MPI *_m) /* * Integer to Octet String conversion [RFC3447 sec 4.1] */ -static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) +static int _RSA_I2OSP(MPI x, unsigned *X_size, u8 **_X) { - unsigned X_size, x_size; int X_sign; u8 *X; + X = mpi_get_buffer(x, X_size, &X_sign); + if (!X) + return -ENOMEM; + if (X_sign < 0) { + kfree(X); + return -EBADMSG; + } + + *_X = X; + return 0; +} + +static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) +{ + unsigned x_size; + unsigned X_size; + u8 *X = NULL; + int ret; + /* Make sure the string is the right length. The number should begin * with { 0x00, 0x01, ... } so we have to account for 15 leading zero * bits not being reported by MPI. @@ -136,13 +154,10 @@ static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X) if (x_size != xLen * 8 - 15) return -ERANGE; - X = mpi_get_buffer(x, &X_size, &X_sign); - if (!X) - return -ENOMEM; - if (X_sign < 0) { - kfree(X); - return -EBADMSG; - } + ret = _RSA_I2OSP(x, &X_size, &X); + if (ret < 0) + return ret; + if (X_size != xLen - 1) { kfree(X); return -EBADMSG;