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authorStephan Mueller <smueller@chronox.de>2014-07-06 02:25:36 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2014-07-08 21:18:25 +0800
commit27e4de2bd1804c24e3e517dd54026c1f60e8fe27 (patch)
tree4f392026252cb1f1fb0a94a84204e424b0001b65 /include/crypto
parent4f150718797ffd539ace231d001eb41b09e13895 (diff)
crypto: drbg - Mix a time stamp into DRBG state
The current locking approach of the DRBG tries to keep the protected code paths very minimal. It is therefore possible that two threads query one DRBG instance at the same time. When thread A requests random numbers, a shadow copy of the DRBG state is created upon which the request for A is processed. After finishing the state for A's request is merged back into the DRBG state. If now thread B requests random numbers from the same DRBG after the request for thread A is received, but before A's shadow state is merged back, the random numbers for B will be identical to the ones for A. Please note that the time window is very small for this scenario. To prevent that there is even a theoretical chance for thread A and B having the same DRBG state, the current time stamp is provided as additional information string for each new request. The addition of the time stamp as additional information string implies that now all generate functions must be capable to process a linked list with additional information strings instead of a scalar. CC: Rafael Aquini <aquini@redhat.com> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/crypto')
-rw-r--r--include/crypto/drbg.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h
index 4065dfca146a..831d786976c5 100644
--- a/include/crypto/drbg.h
+++ b/include/crypto/drbg.h
@@ -102,7 +102,7 @@ struct drbg_state_ops {
int reseed);
int (*generate)(struct drbg_state *drbg,
unsigned char *buf, unsigned int buflen,
- struct drbg_string *addtl);
+ struct list_head *addtl);
int (*crypto_init)(struct drbg_state *drbg);
int (*crypto_fini)(struct drbg_state *drbg);