diff options
| author | Will Deacon <will@kernel.org> | 2023-11-17 13:14:22 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2023-11-22 18:46:05 +0000 |
| commit | acfa60dbe03802d6afd28401aa47801270e82021 (patch) | |
| tree | 91d247bcb84bfbe50b1816d95d13bd82a1985e46 | |
| parent | b85ea95d086471afb4ad062012a4d73cd328fa86 (diff) | |
arm64: mm: Fix "rodata=on" when CONFIG_RODATA_FULL_DEFAULT_ENABLED=y
When CONFIG_RODATA_FULL_DEFAULT_ENABLED=y, passing "rodata=on" on the
kernel command-line (rather than "rodata=full") should turn off the
"full" behaviour, leaving writable linear aliases of read-only kernel
memory. Unfortunately, the option has no effect in this situation and
the only way to disable the "rodata=full" behaviour is to disable rodata
protection entirely by passing "rodata=off".
Fix this by parsing the "on" and "off" options in the arch code,
additionally enforcing that 'rodata_full' cannot be set without also
setting 'rodata_enabled', allowing us to simplify a couple of checks
in the process.
Fixes: 2e8cff0a0eee ("arm64: fix rodata=full")
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20231117131422.29663-1-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/setup.h | 17 | ||||
| -rw-r--r-- | arch/arm64/mm/pageattr.c | 7 |
2 files changed, 18 insertions, 6 deletions
diff --git a/arch/arm64/include/asm/setup.h b/arch/arm64/include/asm/setup.h index f4af547ef54c..2e4d7da74fb8 100644 --- a/arch/arm64/include/asm/setup.h +++ b/arch/arm64/include/asm/setup.h @@ -21,9 +21,22 @@ static inline bool arch_parse_debug_rodata(char *arg) extern bool rodata_enabled; extern bool rodata_full; - if (arg && !strcmp(arg, "full")) { + if (!arg) + return false; + + if (!strcmp(arg, "full")) { + rodata_enabled = rodata_full = true; + return true; + } + + if (!strcmp(arg, "off")) { + rodata_enabled = rodata_full = false; + return true; + } + + if (!strcmp(arg, "on")) { rodata_enabled = true; - rodata_full = true; + rodata_full = false; return true; } diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c index 8e2017ba5f1b..924843f1f661 100644 --- a/arch/arm64/mm/pageattr.c +++ b/arch/arm64/mm/pageattr.c @@ -29,8 +29,8 @@ bool can_set_direct_map(void) * * KFENCE pool requires page-granular mapping if initialized late. */ - return (rodata_enabled && rodata_full) || debug_pagealloc_enabled() || - arm64_kfence_can_set_direct_map(); + return rodata_full || debug_pagealloc_enabled() || + arm64_kfence_can_set_direct_map(); } static int change_page_range(pte_t *ptep, unsigned long addr, void *data) @@ -105,8 +105,7 @@ static int change_memory_common(unsigned long addr, int numpages, * If we are manipulating read-only permissions, apply the same * change to the linear mapping of the pages that back this VM area. */ - if (rodata_enabled && - rodata_full && (pgprot_val(set_mask) == PTE_RDONLY || + if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY || pgprot_val(clear_mask) == PTE_RDONLY)) { for (i = 0; i < area->nr_pages; i++) { __change_memory_common((u64)page_address(area->pages[i]), |