Relanding Porting of HKDF changes from server.

Relanding Porting of HKDF changes from server.

Added a2b_hex function to move common code in hkdf_unittest.cc
and to make it similar to CL - 40300624.

Merge internal CL: 40300624

Original approved CL: https://chromiumcodereview.appspot.com/12326029/

R=agl@chromium.org, rsleevi@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=184306

[ramant (doing other things), 2013-02-22 23:42:33]

Hi Ryan,
  HKDF CL was committed via CQ earlier but was reverted because it failed on XP.

  Checked hkdf.cc's vector. IMO, it shouldn't go out of range. Changed the unit
test to allocate vector only if the slat and info are not empty.

  Could you please take another look?

  The following is the revert:
https://codereview.chromium.org/12330079/

thanks
raman

[Ryan Sleevi, 2013-02-23 00:19:19]

https://codereview.chromium.org/12335045/diff/10002/crypto/hkdf_unittest.cc
File crypto/hkdf_unittest.cc (right):

https://codereview.chromium.org/12335045/diff/10002/crypto/hkdf_unittest.cc#n...
crypto/hkdf_unittest.cc:68: const std::string salt(reinterpret_cast<char
*>(&data[0]), data.size());
std::string salt(test.salt_hex);
if (!salt_hex.empty()) {
  ASSERT_TRUE(..., &data);
  salt->assign(....);
}

[ramant (doing other things), 2013-02-23 00:37:33]

PTAL.

https://codereview.chromium.org/12335045/diff/10002/crypto/hkdf_unittest.cc
File crypto/hkdf_unittest.cc (right):

https://codereview.chromium.org/12335045/diff/10002/crypto/hkdf_unittest.cc#n...
crypto/hkdf_unittest.cc:68: const std::string salt(reinterpret_cast<char
*>(&data[0]), data.size());
On 2013/02/23 00:19:19, Ryan Sleevi wrote:
> std::string salt(test.salt_hex);
> if (!salt_hex.empty()) {
>   ASSERT_TRUE(..., &data);
>   salt->assign(....);
> }

Done.

[Ryan Sleevi, 2013-02-23 00:44:06]

lgtm

https://codereview.chromium.org/12335045/diff/11009/crypto/hkdf_unittest.cc
File crypto/hkdf_unittest.cc (right):

https://codereview.chromium.org/12335045/diff/11009/crypto/hkdf_unittest.cc#n...
crypto/hkdf_unittest.cc:61: const std::string key(reinterpret_cast<char
*>(&data[0]), data.size());
style: reinterpret_cast<char *> -> reinterpret_cast<char*>

see also below

https://codereview.chromium.org/12335045/diff/11009/crypto/hkdf_unittest.cc#n...
crypto/hkdf_unittest.cc:64: // |salt_hex| could be optional.
// |salt_hex| is optional and may be empty.


That is, you would say "could be missing" or "is optional", but you generally
don't say something "could be optional" (because the opposite of "could be
optional" is "could be required", and those are mutually exclusive expressions),
unless it's only optional when some OTHER criteria is met (eg: "salt" could be
optional when data is less than 128 bytes, for example)

[ramant (doing other things), 2013-02-23 00:50:40]

Done. thanks Ryan.

https://codereview.chromium.org/12335045/diff/11009/crypto/hkdf_unittest.cc
File crypto/hkdf_unittest.cc (right):

https://codereview.chromium.org/12335045/diff/11009/crypto/hkdf_unittest.cc#n...
crypto/hkdf_unittest.cc:61: const std::string key(reinterpret_cast<char
*>(&data[0]), data.size());
On 2013/02/23 00:44:06, Ryan Sleevi wrote:
> style: reinterpret_cast<char *> -> reinterpret_cast<char*>
> 
> see also below

Done.

https://codereview.chromium.org/12335045/diff/11009/crypto/hkdf_unittest.cc#n...
crypto/hkdf_unittest.cc:64: // |salt_hex| could be optional.
On 2013/02/23 00:44:06, Ryan Sleevi wrote:
> // |salt_hex| is optional and may be empty.
> 
> 
> That is, you would say "could be missing" or "is optional", but you generally
> don't say something "could be optional" (because the opposite of "could be
> optional" is "could be required", and those are mutually exclusive
expressions),
> unless it's only optional when some OTHER criteria is met (eg: "salt" could be
> optional when data is less than 128 bytes, for example)

Done.

[commit-bot: I haz the power, 2013-02-23 00:52:41]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/rtenneti@chromium.org/12335045/6008

[commit-bot: I haz the power, 2013-02-23 06:47:23]

Change committed as 184306