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4b7a6ce71e
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>
48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/compat.h>
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#include <linux/errno.h>
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#include <linux/prctl.h>
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#include <linux/random.h>
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#include <linux/sched.h>
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#include <asm/cpufeature.h>
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#include <asm/pointer_auth.h>
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int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
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{
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struct ptrauth_keys_user *keys = &tsk->thread.keys_user;
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unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
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PR_PAC_APDAKEY | PR_PAC_APDBKEY;
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unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
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if (!system_supports_address_auth() && !system_supports_generic_auth())
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return -EINVAL;
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if (is_compat_thread(task_thread_info(tsk)))
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return -EINVAL;
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if (!arg) {
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ptrauth_keys_init_user(keys);
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return 0;
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}
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if (arg & ~key_mask)
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return -EINVAL;
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if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
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((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
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return -EINVAL;
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if (arg & PR_PAC_APIAKEY)
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get_random_bytes(&keys->apia, sizeof(keys->apia));
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if (arg & PR_PAC_APIBKEY)
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get_random_bytes(&keys->apib, sizeof(keys->apib));
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if (arg & PR_PAC_APDAKEY)
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get_random_bytes(&keys->apda, sizeof(keys->apda));
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if (arg & PR_PAC_APDBKEY)
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get_random_bytes(&keys->apdb, sizeof(keys->apdb));
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if (arg & PR_PAC_APGAKEY)
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get_random_bytes(&keys->apga, sizeof(keys->apga));
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return 0;
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}
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