Messages in this thread | | | Date | Thu, 20 Aug 2020 17:15:22 +1000 | From | Herbert Xu <> | Subject | Re: [PATCH] crypto: drbg: check blocklen is non zero |
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On Sun, Aug 02, 2020 at 10:12:47AM -0700, trix@redhat.com wrote: > From: Tom Rix <trix@redhat.com> > > Clang static analysis reports this error > > crypto/drbg.c:441:40: warning: Division by zero > padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg)); > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ > > When drbg_bocklen fails it returns 0. > > if (drbg && drbg->core) > return drbg->core->blocklen_bytes; > return 0;
Yes but it can only fail if the drbg is not instantiated. If you're hitting the generate path with an uninstantiated drbg you've got bigger problems than a divide by zero.
So how is this even possible?
Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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