diff options
Diffstat (limited to 'arch/arm64/include/asm')
-rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 8 | ||||
-rw-r--r-- | arch/arm64/include/asm/mman.h | 36 | ||||
-rw-r--r-- | arch/arm64/include/asm/mmu_context.h | 30 |
3 files changed, 73 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index a8f97690ce1f..ee33b7e52da7 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -18,6 +18,7 @@ #define ARM64_SW_FEATURE_OVERRIDE_NOKASLR 0 #define ARM64_SW_FEATURE_OVERRIDE_HVHE 4 #define ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF 8 +#define ARM64_SW_FEATURE_OVERRIDE_NOWXN 12 #ifndef __ASSEMBLY__ @@ -962,6 +963,13 @@ static inline bool kaslr_disabled_cmdline(void) return arm64_test_sw_feature_override(ARM64_SW_FEATURE_OVERRIDE_NOKASLR); } +static inline bool arm64_wxn_enabled(void) +{ + if (!IS_ENABLED(CONFIG_ARM64_WXN)) + return false; + return !arm64_test_sw_feature_override(ARM64_SW_FEATURE_OVERRIDE_NOWXN); +} + u32 get_kvm_ipa_limit(void); void dump_cpu_features(void); diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index 5966ee4a6154..6d4940342ba7 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -35,11 +35,40 @@ static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) } #define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags) +static inline bool arm64_check_wx_prot(unsigned long prot, + struct task_struct *tsk) +{ + /* + * When we are running with SCTLR_ELx.WXN==1, writable mappings are + * implicitly non-executable. This means we should reject such mappings + * when user space attempts to create them using mmap() or mprotect(). + */ + if (arm64_wxn_enabled() && + ((prot & (PROT_WRITE | PROT_EXEC)) == (PROT_WRITE | PROT_EXEC))) { + /* + * User space libraries such as libffi carry elaborate + * heuristics to decide whether it is worth it to even attempt + * to create writable executable mappings, as PaX or selinux + * enabled systems will outright reject it. They will usually + * fall back to something else (e.g., two separate shared + * mmap()s of a temporary file) on failure. + */ + pr_info_ratelimited( + "process %s (%d) attempted to create PROT_WRITE+PROT_EXEC mapping\n", + tsk->comm, tsk->pid); + return false; + } + return true; +} + static inline bool arch_validate_prot(unsigned long prot, unsigned long addr __always_unused) { unsigned long supported = PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM; + if (!arm64_check_wx_prot(prot, current)) + return false; + if (system_supports_bti()) supported |= PROT_BTI; @@ -50,6 +79,13 @@ static inline bool arch_validate_prot(unsigned long prot, } #define arch_validate_prot(prot, addr) arch_validate_prot(prot, addr) +static inline bool arch_validate_mmap_prot(unsigned long prot, + unsigned long addr) +{ + return arm64_check_wx_prot(prot, current); +} +#define arch_validate_mmap_prot arch_validate_mmap_prot + static inline bool arch_validate_flags(unsigned long vm_flags) { if (!system_supports_mte()) diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h index c768d16b81a4..f0fe2d09d139 100644 --- a/arch/arm64/include/asm/mmu_context.h +++ b/arch/arm64/include/asm/mmu_context.h @@ -20,13 +20,41 @@ #include <asm/cpufeature.h> #include <asm/daifflags.h> #include <asm/proc-fns.h> -#include <asm-generic/mm_hooks.h> #include <asm/cputype.h> #include <asm/sysreg.h> #include <asm/tlbflush.h> extern bool rodata_full; +static inline int arch_dup_mmap(struct mm_struct *oldmm, + struct mm_struct *mm) +{ + return 0; +} + +static inline void arch_exit_mmap(struct mm_struct *mm) +{ +} + +static inline void arch_unmap(struct mm_struct *mm, + unsigned long start, unsigned long end) +{ +} + +static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, + bool write, bool execute, bool foreign) +{ + if (IS_ENABLED(CONFIG_ARM64_WXN) && execute && + (vma->vm_flags & (VM_WRITE | VM_EXEC)) == (VM_WRITE | VM_EXEC)) { + pr_warn_ratelimited( + "process %s (%d) attempted to execute from writable memory\n", + current->comm, current->pid); + /* disallow unless the nowxn override is set */ + return !arm64_wxn_enabled(); + } + return true; +} + static inline void contextidr_thread_switch(struct task_struct *next) { if (!IS_ENABLED(CONFIG_PID_IN_CONTEXTIDR)) |