diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2022-03-03 21:00:44 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2022-03-08 13:03:51 +0300 |
| commit | 6e2edd6371a497a6350bb735534c9bda2a31f43d (patch) | |
| tree | 2c7c0ebd1e48ea7301b9674b0d75f7ced5acafe2 /arch/arm64/mm/mmap.c | |
| parent | 4f6de676d94ee8ddfc2e7e7cd935fc7cb2feff3a (diff) | |
| download | linux-6e2edd6371a497a6350bb735534c9bda2a31f43d.tar.xz | |
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/arm64/mm/mmap.c')
| -rw-r--r-- | arch/arm64/mm/mmap.c | 17 |
1 files changed, 17 insertions, 0 deletions
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); |