diff options
author | Dr. Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> | 2017-08-31 23:16:22 +0200 |
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committer | Ben Kaduk <kaduk@mit.edu> | 2017-10-18 08:39:20 -0500 |
commit | c16de9d8329d41a2433d0f273c080d9d06ad7a87 (patch) | |
tree | 3bdcf5e354efd8991aa1f7d83921655e81db726b /crypto/rand/rand_win.c | |
parent | af1d638730bdfad85a7fa8c3f157b2828eda7c1d (diff) |
Fix reseeding issues of the public RAND_DRBG
Reseeding is handled very differently by the classic RAND_METHOD API
and the new RAND_DRBG api. These differences led to some problems when
the new RAND_DRBG was made the default OpenSSL RNG. In particular,
RAND_add() did not work as expected anymore. These issues are discussed
on the thread '[openssl-dev] Plea for a new public OpenSSL RNG API'
and in Pull Request #4328. This commit fixes the mentioned issues,
introducing the following changes:
- Replace the fixed size RAND_BYTES_BUFFER by a new RAND_POOL API which
facilitates collecting entropy by the get_entropy() callback.
- Don't use RAND_poll()/RAND_add() for collecting entropy from the
get_entropy() callback anymore. Instead, replace RAND_poll() by
RAND_POOL_acquire_entropy().
- Add a new function rand_drbg_restart() which tries to get the DRBG
in an instantiated state by all means, regardless of the current
state (uninstantiated, error, ...) the DRBG is in. If the caller
provides entropy or additional input, it will be used for reseeding.
- Restore the original documented behaviour of RAND_add() and RAND_poll()
(namely to reseed the DRBG immediately) by a new implementation based
on rand_drbg_restart().
- Add automatic error recovery from temporary failures of the entropy
source to RAND_DRBG_generate() using the rand_drbg_restart() function.
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4328)
Diffstat (limited to 'crypto/rand/rand_win.c')
-rw-r--r-- | crypto/rand/rand_win.c | 84 |
1 files changed, 54 insertions, 30 deletions
diff --git a/crypto/rand/rand_win.c b/crypto/rand/rand_win.c index 8637ca4185..9eff319bc8 100644 --- a/crypto/rand/rand_win.c +++ b/crypto/rand/rand_win.c @@ -10,7 +10,6 @@ #include "internal/cryptlib.h" #include <openssl/rand.h> #include "rand_lcl.h" - #if defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32) # ifndef OPENSSL_RAND_SEED_OS @@ -39,55 +38,80 @@ # define INTEL_DEF_PROV L"Intel Hardware Cryptographic Service Provider" # endif -int RAND_poll_ex(RAND_poll_cb rand_add, void *arg) +size_t RAND_POOL_acquire_entropy(RAND_POOL *pool) { # ifndef USE_BCRYPTGENRANDOM HCRYPTPROV hProvider; - int ok = 0; # endif - BYTE buf[RANDOMNESS_NEEDED]; + unsigned char *buffer; + size_t bytes_needed; + size_t entropy_available = 0; + # ifdef OPENSSL_RAND_SEED_RDTSC - rand_read_tsc(cb, arg); + entropy_available = rand_acquire_entropy_from_tsc(pool); + if (entropy_available > 0) + return entropy_available; # endif + # ifdef OPENSSL_RAND_SEED_RDCPU - if (rand_read_cpu(cb, arg)) - return 1; + entropy_available = rand_acquire_entropy_from_cpu(pool); + if (entropy_available > 0) + return entropy_available; # endif # ifdef USE_BCRYPTGENRANDOM - if (BCryptGenRandom(NULL, buf, (ULONG)sizeof(buf), - BCRYPT_USE_SYSTEM_PREFERRED_RNG) == STATUS_SUCCESS) { - rand_add(arg, buf, sizeof(buf), sizeof(buf)); - return 1; + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + if (BCryptGenRandom(NULL, buffer, bytes_needed, + BCRYPT_USE_SYSTEM_PREFERRED_RNG) == STATUS_SUCCESS) + bytes = bytes_needed; + + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; # else - /* poll the CryptoAPI PRNG */ - if (CryptAcquireContextW(&hProvider, NULL, NULL, PROV_RSA_FULL, - CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { - if (CryptGenRandom(hProvider, (DWORD)sizeof(buf), buf) != 0) { - rand_add(arg, buf, sizeof(buf), sizeof(buf)); - ok = 1; + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + /* poll the CryptoAPI PRNG */ + if (CryptAcquireContextW(&hProvider, NULL, NULL, PROV_RSA_FULL, + CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { + if (CryptGenRandom(hProvider, bytes_needed, buffer) != 0) + bytes = bytes_needed; + + CryptReleaseContext(hProvider, 0); } - CryptReleaseContext(hProvider, 0); - if (ok) - return 1; + + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; + + bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/); + buffer = RAND_POOL_add_begin(pool, bytes_needed); + if (buffer != NULL) { + size_t bytes = 0; + /* poll the Pentium PRG with CryptoAPI */ + if (CryptAcquireContextW(&hProvider, NULL, + INTEL_DEF_PROV, PROV_INTEL_SEC, + CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { + if (CryptGenRandom(hProvider, bytes_needed, buffer) != 0) + bytes = bytes_needed; - /* poll the Pentium PRG with CryptoAPI */ - if (CryptAcquireContextW(&hProvider, NULL, INTEL_DEF_PROV, PROV_INTEL_SEC, - CRYPT_VERIFYCONTEXT | CRYPT_SILENT) != 0) { - if (CryptGenRandom(hProvider, (DWORD)sizeof(buf), buf) != 0) { - rand_add(arg, buf, sizeof(buf), sizeof(buf)); - ok = 1; + CryptReleaseContext(hProvider, 0); } - CryptReleaseContext(hProvider, 0); - if (ok) - return 1; + entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes); } + if (entropy_available > 0) + return entropy_available; # endif - return 0; + return RAND_POOL_entropy_available(pool); } # if OPENSSL_API_COMPAT < 0x10100000L |