Am Dienstag, 26. August 2014, 16:58:53 schrieb Herbert Xu: Hi Herbert, > On Tue, Aug 26, 2014 at 10:52:45AM +0200, Stephan Mueller wrote: > > Am Dienstag, 26. August 2014, 16:43:43 schrieb Herbert Xu: > > > > Hi Herbert, > > > > > On Tue, Aug 26, 2014 at 10:29:45AM +0200, Stephan Mueller wrote: > > > > The maximum values for additional input string or generated blocks is > > > > larger than 1<<32. To ensure a sensible value on 32 bit systems, > > > > return > > > > SIZE_MAX on 32 bit systems. This value is lower than the maximum > > > > allowed values defined in SP800-90A. The standard allow lower maximum > > > > values, but not larger values. > > > > > > > > SIZE_MAX - 1 is used for drbg_max_addtl to allow > > > > drbg_healthcheck_sanity to check the enforcement of the variable > > > > without wrapping. > > > > > > This is really ugly but OK. However, I'm not sure how the sanity > > > check ever worked. It would appear that the drbg_generate call in > > > drbg_healthcheck_sanity should always fail because you explicitly > > > set addtl->len to drbg_max_addtl + 1, which should trigger the > > > "DRBG: additional information string too long" error, no? > > > > That is exactly what the test shall do: the test is intended to check > > whether the maximum values are enforced. And it does that by checking > > whether an error is returned. > > OK that makes sense. Patch applied. Thanks! I am wondering about the current code in Linus' tree though considering the applied patch: Linus' code contains: static inline size_t drbg_max_addtl(struct drbg_state *drbg) { return (1UL<<(drbg->core->max_addtllen)); } static inline size_t drbg_max_requests(struct drbg_state *drbg) { return (1UL<<(drbg->core->max_req)); } The max_addtllen and max_req are defined in drbg_cores[] in crypto/drbg.c for each DRBG type. As size_t on a 32 bit system is 32 bit the bit shifts would not work either. Thus, I am wondering whether the just applied patch would need to go to Linus tree too? I would think that the following patch would be in order: static inline size_t drbg_max_addtl(struct drbg_state *drbg) { #if (__BITS_PER_LONG == 32) return (SIZE_MAX - 1); #else return (1UL<<(drbg->core->max_addtllen)); #endif } static inline size_t drbg_max_requests(struct drbg_state *drbg) { #if (__BITS_PER_LONG == 32) return SIZE_MAX; #else return (1UL<<(drbg->core->max_req)); #endif } -- Ciao Stephan -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html