From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephan Mueller Subject: [PATCH v2] DRBG: fix maximum value checks on 32 bit systems Date: Tue, 26 Aug 2014 10:29:45 +0200 Message-ID: <2984929.nIbTCa5fhe@myon.chronox.de> References: <20140826161456.7ad100e3@canb.auug.org.au> <1998203.8HHRdZPLvI@myon.chronox.de> <20140826080858.GA4161@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20140826080858.GA4161@gondor.apana.org.au> Sender: linux-kernel-owner@vger.kernel.org To: Herbert Xu Cc: Stephen Rothwell , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-next.vger.kernel.org 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: Stephen Rothwell Reported-by: kbuild test robot Signed-off-by: Stephan Mueller --- include/crypto/drbg.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h index 3d8e73a..5186f75 100644 --- a/include/crypto/drbg.h +++ b/include/crypto/drbg.h @@ -154,13 +154,26 @@ static inline size_t drbg_max_request_bytes(struct drbg_state *drbg) static inline size_t drbg_max_addtl(struct drbg_state *drbg) { /* SP800-90A requires 2**35 bytes additional info str / pers str */ +#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<<35); +#endif } static inline size_t drbg_max_requests(struct drbg_state *drbg) { /* SP800-90A requires 2**48 maximum requests before reseeding */ +#if (__BITS_PER_LONG == 32) + return SIZE_MAX; +#else return (1UL<<48); +#endif } /* -- 1.9.3