diff options
| author | Philip Derrin | 2017-11-14 00:55:25 +0100 |
|---|---|---|
| committer | Russell King | 2017-11-21 15:10:07 +0000 |
| commit | 400eeffaffc7232c0ae1134fe04e14ae4fb48d8c (patch) | |
| tree | a21d5b4f3044abb133eeb03cb12db8664b964abd | |
| parent | 3b0c0c922ff4be275a8beb87ce5657d16f355b54 (diff) | |
ARM: 8722/1: mm: make STRICT_KERNEL_RWX effective for LPAE
Currently, for ARM kernels with CONFIG_ARM_LPAE and
CONFIG_STRICT_KERNEL_RWX enabled, the 2MiB pages mapping the
kernel code and rodata are writable. They are marked read-only in
a software bit (L_PMD_SECT_RDONLY) but the hardware read-only bit
is not set (PMD_SECT_AP2).
For user mappings, the logic that propagates the software bit
to the hardware bit is in set_pmd_at(); but for the kernel,
section_update() writes the PMDs directly, skipping this logic.
The fix is to set PMD_SECT_AP2 for read-only sections in
section_update(), at the same time as L_PMD_SECT_RDONLY.
Fixes: 1e3479225acb ("ARM: 8275/1: mm: fix PMD_SECT_RDONLY undeclared compile error")
Signed-off-by: Philip Derrin <philip@cog.systems>
Reported-by: Neil Dick <neil@cog.systems>
Tested-by: Neil Dick <neil@cog.systems>
Tested-by: Laura Abbott <labbott@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| -rw-r--r-- | arch/arm/mm/init.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index ad80548325fe..0f6d1537f330 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -639,8 +639,8 @@ static struct section_perm ro_perms[] = { .start = (unsigned long)_stext, .end = (unsigned long)__init_begin, #ifdef CONFIG_ARM_LPAE - .mask = ~L_PMD_SECT_RDONLY, - .prot = L_PMD_SECT_RDONLY, + .mask = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2), + .prot = L_PMD_SECT_RDONLY | PMD_SECT_AP2, #else .mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE), .prot = PMD_SECT_APX | PMD_SECT_AP_WRITE, |