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| author | Peter Collingbourne <pcc@google.com> | 2020-10-14 07:24:30 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-10-15 11:50:09 +0200 |
| commit | 4b7a6ce71e033666d6f5a577deb7f1f5126ed889 (patch) | |
| tree | 832be88c15ac3ab6f70f229860190f642185ce2c /arch/arm64/kernel/pointer_auth.c | |
| parent | Revert "arm64: initialize per-cpu offsets earlier" (diff) | |
| download | linux-4b7a6ce71e033666d6f5a577deb7f1f5126ed889.tar.xz linux-4b7a6ce71e033666d6f5a577deb7f1f5126ed889.zip | |
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: Peter 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: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/pointer_auth.c')
| -rw-r--r-- | arch/arm64/kernel/pointer_auth.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/kernel/pointer_auth.c b/arch/arm64/kernel/pointer_auth.c index 1e77736a4f66..adb955fd9bdd 100644 --- a/arch/arm64/kernel/pointer_auth.c +++ b/arch/arm64/kernel/pointer_auth.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 +#include <linux/compat.h> #include <linux/errno.h> #include <linux/prctl.h> #include <linux/random.h> @@ -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()) return -EINVAL; + if (is_compat_thread(task_thread_info(tsk))) + return -EINVAL; + if (!arg) { ptrauth_keys_init_user(keys); return 0; |