Commit fb38ab4c authored by Herbert Xu's avatar Herbert Xu

crypto: drbg - backport "fix maximum value checks on 32 bit systems"

This is a backport of commit b9347aff.
This backport is needed as without it the code will crash on 32-bit
systems.
    
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.
Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 7d1311b9
...@@ -162,12 +162,25 @@ static inline size_t drbg_max_request_bytes(struct drbg_state *drbg) ...@@ -162,12 +162,25 @@ static inline size_t drbg_max_request_bytes(struct drbg_state *drbg)
static inline size_t drbg_max_addtl(struct drbg_state *drbg) static inline size_t drbg_max_addtl(struct drbg_state *drbg)
{ {
#if (__BITS_PER_LONG == 32)
/*
* SP800-90A allows smaller maximum numbers to be returned -- we
* return SIZE_MAX - 1 to allow the verification of the enforcement
* of this value in drbg_healthcheck_sanity.
*/
return (SIZE_MAX - 1);
#else
return (1UL<<(drbg->core->max_addtllen)); return (1UL<<(drbg->core->max_addtllen));
#endif
} }
static inline size_t drbg_max_requests(struct drbg_state *drbg) 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)); return (1UL<<(drbg->core->max_req));
#endif
} }
/* /*
......
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