Commit 4b7a6ce7 authored by Peter Collingbourne's avatar Peter Collingbourne Committed by Will Deacon

arm64: reject prctl(PR_PAC_RESET_KEYS) on compat tasks

It doesn't make sense to issue prctl(PR_PAC_RESET_KEYS) on a
compat task because the 32-bit instruction set does not offer PAuth
instructions. For consistency with other 64-bit only prctls such as
{SET,GET}_TAGGED_ADDR_CTRL, reject the prctl on compat tasks.

Although this is a userspace-visible change, maybe it isn't too late
to make this change given that the hardware isn't available yet and
it's very unlikely that anyone has 32-bit software that actually
depends on this succeeding.
Signed-off-by: default avatarPeter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ie885a1ff84ab498cc9f62d6451e9f2cfd4b1d06a
Link: https://lore.kernel.org/r/20201014052430.11630-1-pcc@google.com
[will: Do the same for the SVE prctl()s]
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent d13027bb
...@@ -678,7 +678,7 @@ int sve_set_current_vl(unsigned long arg) ...@@ -678,7 +678,7 @@ int sve_set_current_vl(unsigned long arg)
vl = arg & PR_SVE_VL_LEN_MASK; vl = arg & PR_SVE_VL_LEN_MASK;
flags = arg & ~vl; flags = arg & ~vl;
if (!system_supports_sve()) if (!system_supports_sve() || is_compat_task())
return -EINVAL; return -EINVAL;
ret = sve_set_vector_length(current, vl, flags); ret = sve_set_vector_length(current, vl, flags);
...@@ -691,7 +691,7 @@ int sve_set_current_vl(unsigned long arg) ...@@ -691,7 +691,7 @@ int sve_set_current_vl(unsigned long arg)
/* PR_SVE_GET_VL */ /* PR_SVE_GET_VL */
int sve_get_current_vl(void) int sve_get_current_vl(void)
{ {
if (!system_supports_sve()) if (!system_supports_sve() || is_compat_task())
return -EINVAL; return -EINVAL;
return sve_prctl_status(0); return sve_prctl_status(0);
......
// SPDX-License-Identifier: GPL-2.0 // SPDX-License-Identifier: GPL-2.0
#include <linux/compat.h>
#include <linux/errno.h> #include <linux/errno.h>
#include <linux/prctl.h> #include <linux/prctl.h>
#include <linux/random.h> #include <linux/random.h>
...@@ -17,6 +18,9 @@ int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg) ...@@ -17,6 +18,9 @@ int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
if (!system_supports_address_auth() && !system_supports_generic_auth()) if (!system_supports_address_auth() && !system_supports_generic_auth())
return -EINVAL; return -EINVAL;
if (is_compat_thread(task_thread_info(tsk)))
return -EINVAL;
if (!arg) { if (!arg) {
ptrauth_keys_init_user(keys); ptrauth_keys_init_user(keys);
return 0; return 0;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment