@@ -25,18 +25,21 @@
#include <asm/vio.h>
-static int pseries_rng_data_read(struct hwrng *rng, u32 *data)
+static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
{
+ u64 buffer[PLPAR_HCALL_BUFSIZE];
+ size_t size = max < 8 ? max : 8;
int rc;
- rc = plpar_hcall(H_RANDOM, (unsigned long *)data);
+ rc = plpar_hcall(H_RANDOM, (unsigned long *)buffer);
if (rc != H_SUCCESS) {
pr_err_ratelimited("H_RANDOM call failed %d\n", rc);
return -EIO;
}
+ memcpy(data, buffer, size);
/* The hypervisor interface returns 64 bits */
- return 8;
+ return size;
}
/**
@@ -55,7 +58,7 @@ static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev)
static struct hwrng pseries_rng = {
.name = KBUILD_MODNAME,
- .data_read = pseries_rng_data_read,
+ .read = pseries_rng_read,
};
static int __init pseries_rng_probe(struct vio_dev *dev,
This is a note to let you know that I have just added a patch titled hwrng: pseries - port to new read API and fix stack corruption to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11-ckt12. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From f196733647ae30de2552360baef6be62a3458a72 Mon Sep 17 00:00:00 2001 From: Greg Kurz <gkurz@linux.vnet.ibm.com> Date: Fri, 31 Oct 2014 07:50:11 +0100 Subject: hwrng: pseries - port to new read API and fix stack corruption commit 24c65bc7037e7d0f362c0df70d17dd72ee64b8b9 upstream. 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@redhat.com> 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@linux.vnet.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/char/hw_random/pseries-rng.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) -- 1.9.1