From 8813800b7d995d8b54ef0a1e16d41fc13d8b5f3a Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Wed, 7 Sep 2016 12:38:07 +0100 Subject: crypto: clear out buffer after timing pbkdf algorithm The 'out' buffer will hold a key derived from master password, so it is best practice to clear this buffer when no longer required. At this time, the code isn't worrying about locking buffers into RAM to prevent swapping sensitive data to disk. Reviewed-by: Eric Blake Signed-off-by: Daniel P. Berrange --- crypto/pbkdf.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'crypto') diff --git a/crypto/pbkdf.c b/crypto/pbkdf.c index 929458b312..e3915058fb 100644 --- a/crypto/pbkdf.c +++ b/crypto/pbkdf.c @@ -67,13 +67,14 @@ uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash, const uint8_t *salt, size_t nsalt, Error **errp) { + uint64_t ret = -1; uint8_t out[32]; uint64_t iterations = (1 << 15); unsigned long long delta_ms, start_ms, end_ms; while (1) { if (qcrypto_pbkdf2_get_thread_cpu(&start_ms, errp) < 0) { - return -1; + goto cleanup; } if (qcrypto_pbkdf2(hash, key, nkey, @@ -81,10 +82,10 @@ uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash, iterations, out, sizeof(out), errp) < 0) { - return -1; + goto cleanup; } if (qcrypto_pbkdf2_get_thread_cpu(&end_ms, errp) < 0) { - return -1; + goto cleanup; } delta_ms = end_ms - start_ms; @@ -100,5 +101,9 @@ uint64_t qcrypto_pbkdf2_count_iters(QCryptoHashAlgorithm hash, iterations = iterations * 1000 / delta_ms; - return iterations; + ret = iterations; + + cleanup: + memset(out, 0, sizeof(out)); + return ret; } -- cgit v1.2.1