| Message ID | 20220808125321.32598-1-will@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [for-stable] arm64: set UXN on swapper page tables | expand |
On Mon, Aug 08, 2022 at 01:53:21PM +0100, Will Deacon wrote: > From: Peter Collingbourne <pcc@google.com> > > [ This issue was fixed upstream by accident in c3cee924bd85 ("arm64: > head: cover entire kernel image in initial ID map") as part of a > large refactoring of the arm64 boot flow. This simple fix is therefore > preferred for -stable backporting ] > > On a system that implements FEAT_EPAN, read/write access to the idmap > is denied because UXN is not set on the swapper PTEs. As a result, > idmap_kpti_install_ng_mappings panics the kernel when accessing > __idmap_kpti_flag. Fix it by setting UXN on these PTEs. > > Fixes: 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN") > Cc: <stable@vger.kernel.org> # 5.15 > Link: https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1 > Signed-off-by: Peter Collingbourne <pcc@google.com> > Acked-by: Will Deacon <will@kernel.org> > Cc: Ard Biesheuvel <ardb@kernel.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Link: https://lore.kernel.org/r/20220719234909.1398992-1-pcc@google.com > Signed-off-by: Will Deacon <will@kernel.org> > --- > arch/arm64/include/asm/kernel-pgtable.h | 4 ++-- > arch/arm64/kernel/head.S | 2 +- > 2 files changed, 3 insertions(+), 3 deletions(-) So this should be added to 5.15.y, 5.18.y, and 5.19.y? Or some subset? thanks, greg k-h
On Mon, Aug 08, 2022 at 03:23:55PM +0200, Greg KH wrote: > On Mon, Aug 08, 2022 at 01:53:21PM +0100, Will Deacon wrote: > > From: Peter Collingbourne <pcc@google.com> > > > > [ This issue was fixed upstream by accident in c3cee924bd85 ("arm64: > > head: cover entire kernel image in initial ID map") as part of a > > large refactoring of the arm64 boot flow. This simple fix is therefore > > preferred for -stable backporting ] > > > > On a system that implements FEAT_EPAN, read/write access to the idmap > > is denied because UXN is not set on the swapper PTEs. As a result, > > idmap_kpti_install_ng_mappings panics the kernel when accessing > > __idmap_kpti_flag. Fix it by setting UXN on these PTEs. > > > > Fixes: 18107f8a2df6 ("arm64: Support execute-only permissions with Enhanced PAN") > > Cc: <stable@vger.kernel.org> # 5.15 > > Link: https://linux-review.googlesource.com/id/Ic452fa4b4f74753e54f71e61027e7222a0fae1b1 > > Signed-off-by: Peter Collingbourne <pcc@google.com> > > Acked-by: Will Deacon <will@kernel.org> > > Cc: Ard Biesheuvel <ardb@kernel.org> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Link: https://lore.kernel.org/r/20220719234909.1398992-1-pcc@google.com > > Signed-off-by: Will Deacon <will@kernel.org> > > --- > > arch/arm64/include/asm/kernel-pgtable.h | 4 ++-- > > arch/arm64/kernel/head.S | 2 +- > > 2 files changed, 3 insertions(+), 3 deletions(-) > > So this should be added to 5.15.y, 5.18.y, and 5.19.y? Or some subset? Yes, all of them. Basically anything still being updated which is >= 5.15 and <= 5.19. Thanks, Will
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index 96dc0f7da258..a971d462f531 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -103,8 +103,8 @@ /* * Initial memory map attributes. */ -#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED) -#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S) +#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED | PTE_UXN) +#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S | PMD_SECT_UXN) #if ARM64_KERNEL_USES_PMD_MAPS #define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 6a98f1a38c29..8a93a0a7489b 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -285,7 +285,7 @@ SYM_FUNC_START_LOCAL(__create_page_tables) subs x1, x1, #64 b.ne 1b - mov x7, SWAPPER_MM_MMUFLAGS + mov_q x7, SWAPPER_MM_MMUFLAGS /* * Create the identity mapping.