| Message ID | 20200226155714.43937-6-broonie@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v7,01/11] ELF: UAPI and Kconfig additions for ELF program properties | expand |
On Wed, Feb 26, 2020 at 03:57:08PM +0000, Mark Brown wrote: > From: Dave Martin <Dave.Martin@arm.com> > > For BTI protection to be as comprehensive as possible, it is > desirable to have BTI enabled from process startup. If this is not > done, the process must use mprotect() to enable BTI for each of its > executable mappings, but this is painful to do in the libc startup > code. It's simpler and more sound to have the kernel do it > instead. > > To this end, detect BTI support in the executable (or ELF > interpreter, as appropriate), via the > NT_GNU_PROGRAM_PROPERTY_TYPE_0 note, and tweak the initial prot > flags for the process' executable pages to include PROT_BTI as > appropriate. > > Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Kees Cook <keescook@chromium.org> -Kees > Signed-off-by: Mark Brown <broonie@kernel.org> > --- > arch/arm64/Kconfig | 3 +++ > arch/arm64/include/asm/elf.h | 51 ++++++++++++++++++++++++++++++++++++ > arch/arm64/kernel/process.c | 19 ++++++++++++++ > include/uapi/linux/elf.h | 6 +++++ > 4 files changed, 79 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index e37f4f07b990..d65d226a77ec 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -9,6 +9,7 @@ config ARM64 > select ACPI_MCFG if (ACPI && PCI) > select ACPI_SPCR_TABLE if ACPI > select ACPI_PPTT if ACPI > + select ARCH_BINFMT_ELF_STATE > select ARCH_CLOCKSOURCE_DATA > select ARCH_HAS_DEBUG_VIRTUAL > select ARCH_HAS_DEVMEM_IS_ALLOWED > @@ -33,6 +34,7 @@ config ARM64 > select ARCH_HAS_SYSCALL_WRAPPER > select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > + select ARCH_HAVE_ELF_PROT > select ARCH_HAVE_NMI_SAFE_CMPXCHG > select ARCH_INLINE_READ_LOCK if !PREEMPTION > select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION > @@ -62,6 +64,7 @@ config ARM64 > select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION > select ARCH_KEEP_MEMBLOCK > select ARCH_USE_CMPXCHG_LOCKREF > + select ARCH_USE_GNU_PROPERTY if BINFMT_ELF > select ARCH_USE_QUEUED_RWLOCKS > select ARCH_USE_QUEUED_SPINLOCKS > select ARCH_SUPPORTS_MEMORY_FAILURE > diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h > index b618017205a3..c72e381fa86d 100644 > --- a/arch/arm64/include/asm/elf.h > +++ b/arch/arm64/include/asm/elf.h > @@ -114,7 +114,11 @@ > > #ifndef __ASSEMBLY__ > > +#include <uapi/linux/elf.h> > #include <linux/bug.h> > +#include <linux/errno.h> > +#include <linux/fs.h> > +#include <linux/types.h> > #include <asm/processor.h> /* for signal_minsigstksz, used by ARCH_DLINFO */ > > typedef unsigned long elf_greg_t; > @@ -224,6 +228,53 @@ extern int aarch32_setup_additional_pages(struct linux_binprm *bprm, > > #endif /* CONFIG_COMPAT */ > > +struct arch_elf_state { > + int flags; > +}; > + > +#define ARM64_ELF_BTI (1 << 0) > + > +#define INIT_ARCH_ELF_STATE { \ > + .flags = 0, \ > +} > + > +static inline int arch_parse_elf_property(u32 type, const void *data, > + size_t datasz, bool compat, > + struct arch_elf_state *arch) > +{ > + /* No known properties for AArch32 yet */ > + if (IS_ENABLED(CONFIG_COMPAT) && compat) > + return 0; > + > + if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) { > + const u32 *p = data; > + > + if (datasz != sizeof(*p)) > + return -ENOEXEC; > + > + if (IS_ENABLED(CONFIG_ARM64_BTI) && > + system_supports_bti() && > + (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) > + arch->flags |= ARM64_ELF_BTI; > + } > + > + return 0; > +} > + > +static inline int arch_elf_pt_proc(void *ehdr, void *phdr, > + struct file *f, bool is_interp, > + struct arch_elf_state *state) > +{ > + return 0; > +} > + > +static inline int arch_check_elf(void *ehdr, bool has_interp, > + void *interp_ehdr, > + struct arch_elf_state *state) > +{ > + return 0; > +} > + > #endif /* !__ASSEMBLY__ */ > > #endif > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 00626057a384..b8e3faa8d406 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -11,6 +11,7 @@ > > #include <linux/compat.h> > #include <linux/efi.h> > +#include <linux/elf.h> > #include <linux/export.h> > #include <linux/sched.h> > #include <linux/sched/debug.h> > @@ -18,6 +19,7 @@ > #include <linux/sched/task_stack.h> > #include <linux/kernel.h> > #include <linux/lockdep.h> > +#include <linux/mman.h> > #include <linux/mm.h> > #include <linux/stddef.h> > #include <linux/sysctl.h> > @@ -654,3 +656,20 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void) > if (system_capabilities_finalized()) > preempt_schedule_irq(); > } > + > +#ifdef CONFIG_BINFMT_ELF > +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, > + bool has_interp, bool is_interp) > +{ > + if (is_interp != has_interp) > + return prot; > + > + if (!(state->flags & ARM64_ELF_BTI)) > + return prot; > + > + if (prot & PROT_EXEC) > + prot |= PROT_BTI; > + > + return prot; > +} > +#endif > diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h > index 20900f4496b7..c6dd0215482e 100644 > --- a/include/uapi/linux/elf.h > +++ b/include/uapi/linux/elf.h > @@ -448,4 +448,10 @@ typedef struct elf64_note { > Elf64_Word n_type; /* Content type */ > } Elf64_Nhdr; > > +/* .note.gnu.property types for EM_AARCH64: */ > +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 > + > +/* Bits for GNU_PROPERTY_AARCH64_FEATURE_1_BTI */ > +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) > + > #endif /* _UAPI_LINUX_ELF_H */ > -- > 2.20.1 >
Hi Mark, On 2/26/20 9:27 PM, Mark Brown wrote: > From: Dave Martin <Dave.Martin@arm.com> > > For BTI protection to be as comprehensive as possible, it is > desirable to have BTI enabled from process startup. If this is not > done, the process must use mprotect() to enable BTI for each of its > executable mappings, but this is painful to do in the libc startup > code. It's simpler and more sound to have the kernel do it > instead. > > To this end, detect BTI support in the executable (or ELF > interpreter, as appropriate), via the > NT_GNU_PROGRAM_PROPERTY_TYPE_0 note, and tweak the initial prot > flags for the process' executable pages to include PROT_BTI as > appropriate. > > Signed-off-by: Dave Martin <Dave.Martin@arm.com> > Signed-off-by: Mark Brown <broonie@kernel.org> > --- > arch/arm64/Kconfig | 3 +++ > arch/arm64/include/asm/elf.h | 51 ++++++++++++++++++++++++++++++++++++ > arch/arm64/kernel/process.c | 19 ++++++++++++++ > include/uapi/linux/elf.h | 6 +++++ > 4 files changed, 79 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index e37f4f07b990..d65d226a77ec 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -9,6 +9,7 @@ config ARM64 > select ACPI_MCFG if (ACPI && PCI) > select ACPI_SPCR_TABLE if ACPI > select ACPI_PPTT if ACPI > + select ARCH_BINFMT_ELF_STATE > select ARCH_CLOCKSOURCE_DATA > select ARCH_HAS_DEBUG_VIRTUAL > select ARCH_HAS_DEVMEM_IS_ALLOWED > @@ -33,6 +34,7 @@ config ARM64 > select ARCH_HAS_SYSCALL_WRAPPER > select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > + select ARCH_HAVE_ELF_PROT > select ARCH_HAVE_NMI_SAFE_CMPXCHG > select ARCH_INLINE_READ_LOCK if !PREEMPTION > select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION > @@ -62,6 +64,7 @@ config ARM64 > select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION > select ARCH_KEEP_MEMBLOCK > select ARCH_USE_CMPXCHG_LOCKREF > + select ARCH_USE_GNU_PROPERTY if BINFMT_ELF > select ARCH_USE_QUEUED_RWLOCKS > select ARCH_USE_QUEUED_SPINLOCKS > select ARCH_SUPPORTS_MEMORY_FAILURE > diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h > index b618017205a3..c72e381fa86d 100644 > --- a/arch/arm64/include/asm/elf.h > +++ b/arch/arm64/include/asm/elf.h > @@ -114,7 +114,11 @@ > > #ifndef __ASSEMBLY__ > > +#include <uapi/linux/elf.h> > #include <linux/bug.h> > +#include <linux/errno.h> > +#include <linux/fs.h> > +#include <linux/types.h> > #include <asm/processor.h> /* for signal_minsigstksz, used by ARCH_DLINFO */ > > typedef unsigned long elf_greg_t; > @@ -224,6 +228,53 @@ extern int aarch32_setup_additional_pages(struct linux_binprm *bprm, > > #endif /* CONFIG_COMPAT */ > > +struct arch_elf_state { > + int flags; > +}; > + > +#define ARM64_ELF_BTI (1 << 0) > + > +#define INIT_ARCH_ELF_STATE { \ > + .flags = 0, \ > +} > + > +static inline int arch_parse_elf_property(u32 type, const void *data, > + size_t datasz, bool compat, > + struct arch_elf_state *arch) > +{ > + /* No known properties for AArch32 yet */ > + if (IS_ENABLED(CONFIG_COMPAT) && compat) > + return 0; > + > + if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) { > + const u32 *p = data; > + > + if (datasz != sizeof(*p)) > + return -ENOEXEC; > + > + if (IS_ENABLED(CONFIG_ARM64_BTI) && > + system_supports_bti() && system_supports_bti() has inbuilt CONFIG_ARM64_BTI config check. For all the patch in the series. Reviewed-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Cheers, Amit > + (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) > + arch->flags |= ARM64_ELF_BTI; > + } > + > + return 0; > +} > + > +static inline int arch_elf_pt_proc(void *ehdr, void *phdr, > + struct file *f, bool is_interp, > + struct arch_elf_state *state) > +{ > + return 0; > +} > + > +static inline int arch_check_elf(void *ehdr, bool has_interp, > + void *interp_ehdr, > + struct arch_elf_state *state) > +{ > + return 0; > +} > + > #endif /* !__ASSEMBLY__ */ > > #endif > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 00626057a384..b8e3faa8d406 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -11,6 +11,7 @@ > > #include <linux/compat.h> > #include <linux/efi.h> > +#include <linux/elf.h> > #include <linux/export.h> > #include <linux/sched.h> > #include <linux/sched/debug.h> > @@ -18,6 +19,7 @@ > #include <linux/sched/task_stack.h> > #include <linux/kernel.h> > #include <linux/lockdep.h> > +#include <linux/mman.h> > #include <linux/mm.h> > #include <linux/stddef.h> > #include <linux/sysctl.h> > @@ -654,3 +656,20 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void) > if (system_capabilities_finalized()) > preempt_schedule_irq(); > } > + > +#ifdef CONFIG_BINFMT_ELF > +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, > + bool has_interp, bool is_interp) > +{ > + if (is_interp != has_interp) > + return prot; > + > + if (!(state->flags & ARM64_ELF_BTI)) > + return prot; > + > + if (prot & PROT_EXEC) > + prot |= PROT_BTI; > + > + return prot; > +} > +#endif > diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h > index 20900f4496b7..c6dd0215482e 100644 > --- a/include/uapi/linux/elf.h > +++ b/include/uapi/linux/elf.h > @@ -448,4 +448,10 @@ typedef struct elf64_note { > Elf64_Word n_type; /* Content type */ > } Elf64_Nhdr; > > +/* .note.gnu.property types for EM_AARCH64: */ > +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 > + > +/* Bits for GNU_PROPERTY_AARCH64_FEATURE_1_BTI */ > +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) > + > #endif /* _UAPI_LINUX_ELF_H */ >
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index e37f4f07b990..d65d226a77ec 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -9,6 +9,7 @@ config ARM64 select ACPI_MCFG if (ACPI && PCI) select ACPI_SPCR_TABLE if ACPI select ACPI_PPTT if ACPI + select ARCH_BINFMT_ELF_STATE select ARCH_CLOCKSOURCE_DATA select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEVMEM_IS_ALLOWED @@ -33,6 +34,7 @@ config ARM64 select ARCH_HAS_SYSCALL_WRAPPER select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST + select ARCH_HAVE_ELF_PROT select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_INLINE_READ_LOCK if !PREEMPTION select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION @@ -62,6 +64,7 @@ config ARM64 select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION select ARCH_KEEP_MEMBLOCK select ARCH_USE_CMPXCHG_LOCKREF + select ARCH_USE_GNU_PROPERTY if BINFMT_ELF select ARCH_USE_QUEUED_RWLOCKS select ARCH_USE_QUEUED_SPINLOCKS select ARCH_SUPPORTS_MEMORY_FAILURE diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index b618017205a3..c72e381fa86d 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -114,7 +114,11 @@ #ifndef __ASSEMBLY__ +#include <uapi/linux/elf.h> #include <linux/bug.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/types.h> #include <asm/processor.h> /* for signal_minsigstksz, used by ARCH_DLINFO */ typedef unsigned long elf_greg_t; @@ -224,6 +228,53 @@ extern int aarch32_setup_additional_pages(struct linux_binprm *bprm, #endif /* CONFIG_COMPAT */ +struct arch_elf_state { + int flags; +}; + +#define ARM64_ELF_BTI (1 << 0) + +#define INIT_ARCH_ELF_STATE { \ + .flags = 0, \ +} + +static inline int arch_parse_elf_property(u32 type, const void *data, + size_t datasz, bool compat, + struct arch_elf_state *arch) +{ + /* No known properties for AArch32 yet */ + if (IS_ENABLED(CONFIG_COMPAT) && compat) + return 0; + + if (type == GNU_PROPERTY_AARCH64_FEATURE_1_AND) { + const u32 *p = data; + + if (datasz != sizeof(*p)) + return -ENOEXEC; + + if (IS_ENABLED(CONFIG_ARM64_BTI) && + system_supports_bti() && + (*p & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) + arch->flags |= ARM64_ELF_BTI; + } + + return 0; +} + +static inline int arch_elf_pt_proc(void *ehdr, void *phdr, + struct file *f, bool is_interp, + struct arch_elf_state *state) +{ + return 0; +} + +static inline int arch_check_elf(void *ehdr, bool has_interp, + void *interp_ehdr, + struct arch_elf_state *state) +{ + return 0; +} + #endif /* !__ASSEMBLY__ */ #endif diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 00626057a384..b8e3faa8d406 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -11,6 +11,7 @@ #include <linux/compat.h> #include <linux/efi.h> +#include <linux/elf.h> #include <linux/export.h> #include <linux/sched.h> #include <linux/sched/debug.h> @@ -18,6 +19,7 @@ #include <linux/sched/task_stack.h> #include <linux/kernel.h> #include <linux/lockdep.h> +#include <linux/mman.h> #include <linux/mm.h> #include <linux/stddef.h> #include <linux/sysctl.h> @@ -654,3 +656,20 @@ asmlinkage void __sched arm64_preempt_schedule_irq(void) if (system_capabilities_finalized()) preempt_schedule_irq(); } + +#ifdef CONFIG_BINFMT_ELF +int arch_elf_adjust_prot(int prot, const struct arch_elf_state *state, + bool has_interp, bool is_interp) +{ + if (is_interp != has_interp) + return prot; + + if (!(state->flags & ARM64_ELF_BTI)) + return prot; + + if (prot & PROT_EXEC) + prot |= PROT_BTI; + + return prot; +} +#endif diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h index 20900f4496b7..c6dd0215482e 100644 --- a/include/uapi/linux/elf.h +++ b/include/uapi/linux/elf.h @@ -448,4 +448,10 @@ typedef struct elf64_note { Elf64_Word n_type; /* Content type */ } Elf64_Nhdr; +/* .note.gnu.property types for EM_AARCH64: */ +#define GNU_PROPERTY_AARCH64_FEATURE_1_AND 0xc0000000 + +/* Bits for GNU_PROPERTY_AARCH64_FEATURE_1_BTI */ +#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI (1U << 0) + #endif /* _UAPI_LINUX_ELF_H */