| commit | 5833dd807e3deab0d3ba110f8692e16aa4d78ed5 | [log] [tgz] |
|---|---|---|
| author | David Benjamin <davidben@google.com> | Sat Mar 03 22:07:49 2018 -0500 |
| committer | Adam Langley <alangley@gmail.com> | Fri Mar 30 19:54:18 2018 +0000 |
| tree | 976f0abd6bb04007990565763e6b1a3ac692c3e4 | |
| parent | c1c6eeb5e2ffcfa960b60c83f96964d4372bcb32 [diff] |
Limit the public exponent in RSA_generate_key_ex. Windows CryptoAPI and Go bound public exponents at 2^32-1, so don't generate keys which would violate that. https://github.com/golang/go/issues/3161 https://msdn.microsoft.com/en-us/library/aa387685(VS.85).aspx BoringSSL itself also enforces a 33-bit limit. I don't currently have plans to take much advantage of it, but the modular inverse step and one of the GCDs in RSA key generation are helped by small public exponents[0]. In case someone feels inspired later, get this limit enforced now. Use 32-bits as that's a more convenient limit, and there's no requirement to produce e=2^32+1 keys. (Is there still a requirement to accept them?) [0] This isn't too bad, but it's only worth it if it produces simpler or smaller code. RSA keygen is not performance-critical. 1. Make bn_mod_u16_consttime work for uint32_t. It only barely doesn't work. Maybe only accept 3 and 65537 and pre-compute, maybe call into bn_div_rem_words and friends, maybe just tighten the bound a hair longer. 2. Implement bn_div_u32_consttime by incorporating 32-bit chunks much like bn_mod_u32_consttime. 3. Perform one normal Euclidean algorithm iteration rather than using the binary version. u, v, B, and D are now single words, while A and C are full-width. 4. Continue with binary Euclidean algorithm (u and v are still secret), taking advantage of most values being small. Update-Note: RSA_generate_key_ex will no longer generate keys with public exponents larger than 2^32-1. Everyone uses 65537, save some folks who use 3, so this shouldn't matter. Change-Id: I0d28a29a30d9ff73bff282e34dd98e2b64c35c79 Reviewed-on: https://boringssl-review.googlesource.com/26365 Reviewed-by: Adam Langley <alangley@gmail.com>
BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.
Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.
Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.
BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.
Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.
There are other files in this directory which might be helpful: