From d7992f42c61d5dc6d164f7dddd05284485204ada Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Wed, 28 Jan 2009 15:20:51 +1100 Subject: crypto: ansi_cprng - Force reset on allocation Pseudo RNGs provide predictable outputs based on input parateters {key, V, DT}, the idea behind them is that only the user should know what the inputs are. While its nice to have default known values for testing purposes, it seems dangerous to allow the use of those default values without some sort of safety measure in place, lest an attacker easily guess the output of the cprng. This patch forces the NEED_RESET flag on when allocating a cprng context, so that any user is forced to reseed it before use. The defaults can still be used for testing, but this will prevent their inadvertent use, and be more secure. Signed-off-by: Neil Horman Signed-off-by: Herbert Xu --- crypto/ansi_cprng.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'crypto/ansi_cprng.c') diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c index 0fac8ffc2fb7..74478061ac0c 100644 --- a/crypto/ansi_cprng.c +++ b/crypto/ansi_cprng.c @@ -338,7 +338,16 @@ static int cprng_init(struct crypto_tfm *tfm) spin_lock_init(&ctx->prng_lock); - return reset_prng_context(ctx, NULL, DEFAULT_PRNG_KSZ, NULL, NULL); + if (reset_prng_context(ctx, NULL, DEFAULT_PRNG_KSZ, NULL, NULL) < 0) + return -EINVAL; + + /* + * after allocation, we should always force the user to reset + * so they don't inadvertently use the insecure default values + * without specifying them intentially + */ + ctx->flags |= PRNG_NEED_RESET; + return 0; } static void cprng_exit(struct crypto_tfm *tfm) -- cgit From c5b1e545a567c52081239bd5d187669640d0146f Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Thu, 5 Feb 2009 16:01:38 +1100 Subject: crypto: ansi_cprng - Panic on CPRNG test failure when in FIPS mode FIPS 140-2 specifies that all access to various cryptographic modules be prevented in the event that any of the provided self tests fail on the various implemented algorithms. We already panic when any of the test in testmgr.c fail when we are operating in fips mode. The continuous test in the cprng here was missed when that was implmented. This code simply checks for the fips_enabled flag if the test fails, and warns us via syslog or panics the box accordingly. Signed-off-by: Neil Horman Signed-off-by: Herbert Xu --- crypto/ansi_cprng.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'crypto/ansi_cprng.c') diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c index 74478061ac0c..d80ed4c1e009 100644 --- a/crypto/ansi_cprng.c +++ b/crypto/ansi_cprng.c @@ -132,9 +132,15 @@ static int _get_more_prng_bytes(struct prng_context *ctx) */ if (!memcmp(ctx->rand_data, ctx->last_rand_data, DEFAULT_BLK_SZ)) { + if (fips_enabled) { + panic("cprng %p Failed repetition check!\n", + ctx); + } + printk(KERN_ERR "ctx %p Failed repetition check!\n", ctx); + ctx->flags |= PRNG_NEED_RESET; return -EINVAL; } -- cgit