On Fri, Oct 31, 2014 at 07:50:11AM +0100, Greg Kurz wrote: > The add_early_randomness() function in drivers/char/hw_random/core.c passes > a 16-byte buffer to pseries_rng_data_read(). Unfortunately, plpar_hcall() > returns four 64-bit values and trashes 16 bytes on the stack. > > This bug has been lying around for a long time. It got unveiled by: > > commit d3cc7996473a7bdd33256029988ea690754e4e2a > Author: Amit Shah <amit.shah@xxxxxxxxxx> > Date: Thu Jul 10 15:42:34 2014 +0530 > > hwrng: fetch randomness only after device init > > It may trig a oops while loading or unloading the pseries-rng module for both > PowerVM and PowerKVM guests. > > This patch does two things: > - pass an intermediate well sized buffer to plpar_hcall(). This is acceptalbe > since we're not on a hot path. > - move to the new read API so that we know the return buffer size for sure. > > Signed-off-by: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx> Patch applied to crypto. Thanks, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html