aboutsummaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorCatalin Marinas2022-03-03 18:00:44 +0000
committerCatalin Marinas2022-03-08 10:03:51 +0000
commit6e2edd6371a497a6350bb735534c9bda2a31f43d (patch)
tree2c7c0ebd1e48ea7301b9674b0d75f7ced5acafe2 /arch
parent4f6de676d94ee8ddfc2e7e7cd935fc7cb2feff3a (diff)
arm64: Ensure execute-only permissions are not allowed without EPAN
Commit 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN") re-introduced execute-only permissions when EPAN is available. When EPAN is not available, arch_filter_pgprot() is supposed to change a PAGE_EXECONLY permission into PAGE_READONLY_EXEC. However, if BTI or MTE are present, such check does not detect the execute-only pgprot in the presence of PTE_GP (BTI) or MT_NORMAL_TAGGED (MTE), allowing the user to request PROT_EXEC with PROT_BTI or PROT_MTE. Remove the arch_filter_pgprot() function, change the default VM_EXEC permissions to PAGE_READONLY_EXEC and update the protection_map[] array at core_initcall() if EPAN is detected. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Fixes: 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN") Cc: <stable@vger.kernel.org> # 5.13.x Acked-by: Will Deacon <will@kernel.org> Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com> Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/Kconfig3
-rw-r--r--arch/arm64/include/asm/pgtable-prot.h4
-rw-r--r--arch/arm64/include/asm/pgtable.h11
-rw-r--r--arch/arm64/mm/mmap.c17
4 files changed, 19 insertions, 16 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c7a474f71eb4..f711a8eee6ff 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1236,9 +1236,6 @@ config HW_PERF_EVENTS
def_bool y
depends on ARM_PMU
-config ARCH_HAS_FILTER_PGPROT
- def_bool y
-
# Supported by clang >= 7.0
config CC_HAVE_SHADOW_CALL_STACK
def_bool $(cc-option, -fsanitize=shadow-call-stack -ffixed-x18)
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 7032f04c8ac6..b1e1b74d993c 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/arch/arm64/include/asm/pgtable-prot.h
@@ -92,7 +92,7 @@ extern bool arm64_use_ng_mappings;
#define __P001 PAGE_READONLY
#define __P010 PAGE_READONLY
#define __P011 PAGE_READONLY
-#define __P100 PAGE_EXECONLY
+#define __P100 PAGE_READONLY_EXEC /* PAGE_EXECONLY if Enhanced PAN */
#define __P101 PAGE_READONLY_EXEC
#define __P110 PAGE_READONLY_EXEC
#define __P111 PAGE_READONLY_EXEC
@@ -101,7 +101,7 @@ extern bool arm64_use_ng_mappings;
#define __S001 PAGE_READONLY
#define __S010 PAGE_SHARED
#define __S011 PAGE_SHARED
-#define __S100 PAGE_EXECONLY
+#define __S100 PAGE_READONLY_EXEC /* PAGE_EXECONLY if Enhanced PAN */
#define __S101 PAGE_READONLY_EXEC
#define __S110 PAGE_SHARED_EXEC
#define __S111 PAGE_SHARED_EXEC
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index c4ba047a82d2..94e147e5456c 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -1017,17 +1017,6 @@ static inline bool arch_wants_old_prefaulted_pte(void)
}
#define arch_wants_old_prefaulted_pte arch_wants_old_prefaulted_pte
-static inline pgprot_t arch_filter_pgprot(pgprot_t prot)
-{
- if (cpus_have_const_cap(ARM64_HAS_EPAN))
- return prot;
-
- if (pgprot_val(prot) != pgprot_val(PAGE_EXECONLY))
- return prot;
-
- return PAGE_READONLY_EXEC;
-}
-
static inline bool pud_sect_supported(void)
{
return PAGE_SIZE == SZ_4K;
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index a38f54cd638c..77ada00280d9 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -7,8 +7,10 @@
#include <linux/io.h>
#include <linux/memblock.h>
+#include <linux/mm.h>
#include <linux/types.h>
+#include <asm/cpufeature.h>
#include <asm/page.h>
/*
@@ -38,3 +40,18 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
{
return !(((pfn << PAGE_SHIFT) + size) & ~PHYS_MASK);
}
+
+static int __init adjust_protection_map(void)
+{
+ /*
+ * With Enhanced PAN we can honour the execute-only permissions as
+ * there is no PAN override with such mappings.
+ */
+ if (cpus_have_const_cap(ARM64_HAS_EPAN)) {
+ protection_map[VM_EXEC] = PAGE_EXECONLY;
+ protection_map[VM_EXEC | VM_SHARED] = PAGE_EXECONLY;
+ }
+
+ return 0;
+}
+arch_initcall(adjust_protection_map);