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authorNeil Horman <nhorman@redhat.com>2009-01-27 23:20:51 -0500
committerHerbert Xu <herbert@gondor.apana.org.au>2009-02-18 03:48:06 -0500
commitd7992f42c61d5dc6d164f7dddd05284485204ada (patch)
tree02e6d942f6859ad9cd0e8d7c2cd56bf84bc2f54a /crypto/ansi_cprng.c
parent54b6a1bd5364aca95cd6ffae00f2b64c6511122c (diff)
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 <nhorman@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/ansi_cprng.c')
-rw-r--r--crypto/ansi_cprng.c11
1 files changed, 10 insertions, 1 deletions
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)
338 338
339 spin_lock_init(&ctx->prng_lock); 339 spin_lock_init(&ctx->prng_lock);
340 340
341 return reset_prng_context(ctx, NULL, DEFAULT_PRNG_KSZ, NULL, NULL); 341 if (reset_prng_context(ctx, NULL, DEFAULT_PRNG_KSZ, NULL, NULL) < 0)
342 return -EINVAL;
343
344 /*
345 * after allocation, we should always force the user to reset
346 * so they don't inadvertently use the insecure default values
347 * without specifying them intentially
348 */
349 ctx->flags |= PRNG_NEED_RESET;
350 return 0;
342} 351}
343 352
344static void cprng_exit(struct crypto_tfm *tfm) 353static void cprng_exit(struct crypto_tfm *tfm)