Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
powerpc/book3s64/kup: Check max key supported before enabling kup
Don't enable KUEP/KUAP if we support less than or equal to 3 keys.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201202043854.76406-1-aneesh.kumar@linux.ibm.com
authored by
Aneesh Kumar K.V
and committed by
Michael Ellerman
61130e20
c91435d9
+26
-14
+3
arch/powerpc/include/asm/kup.h
+3
arch/powerpc/include/asm/kup.h
+21
-12
arch/powerpc/mm/book3s64/pkeys.c
+21
-12
arch/powerpc/mm/book3s64/pkeys.c
···
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default_uamor &= ~(0x3ul << pkeyshift(execute_only_key));
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}
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if (unlikely(num_pkey <= 3)) {
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/*
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* Insufficient number of keys to support
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* KUAP/KUEP feature.
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*/
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disable_kuep = true;
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disable_kuap = true;
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WARN(1, "Disabling kernel user protection due to low (%d) max supported keys\n", num_pkey);
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} else {
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/* handle key which is used by kernel for KAUP */
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reserved_allocation_mask |= (0x1 << 3);
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/*
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* Mark access for kup_key in default amr so that
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* we continue to operate with that AMR in
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* copy_to/from_user().
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*/
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default_amr &= ~(0x3ul << pkeyshift(3));
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default_iamr &= ~(0x1ul << pkeyshift(3));
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default_uamor &= ~(0x3ul << pkeyshift(3));
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}
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+
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/*
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* Allow access for only key 0. And prevent any other modification.
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*/
···
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*/
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reserved_allocation_mask |= (0x1 << 1);
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default_uamor &= ~(0x3ul << pkeyshift(1));
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-
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/* handle key which is used by kernel for KAUP */
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reserved_allocation_mask |= (0x1 << 3);
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-
/*
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* Mark access for KUAP key in default amr so that
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* we continue to operate with that AMR in
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* copy_to/from_user().
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*/
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default_amr &= ~(0x3ul << pkeyshift(3));
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default_iamr &= ~(0x1ul << pkeyshift(3));
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default_uamor &= ~(0x3ul << pkeyshift(3));
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-
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/*
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* Prevent the usage of OS reserved keys. Update UAMOR
+2
-2
arch/powerpc/mm/init-common.c
+2
-2
arch/powerpc/mm/init-common.c
···
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unsigned long kernstart_virt_addr __ro_after_init = KERNELBASE;
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EXPORT_SYMBOL_GPL(kernstart_virt_addr);
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-
static bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
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-
static bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
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bool disable_kuep = !IS_ENABLED(CONFIG_PPC_KUEP);
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bool disable_kuap = !IS_ENABLED(CONFIG_PPC_KUAP);
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static int __init parse_nosmep(char *p)
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{