diff options
Diffstat (limited to 'include/linux/mman.h')
| -rw-r--r-- | include/linux/mman.h | 162 |
1 files changed, 147 insertions, 15 deletions
diff --git a/include/linux/mman.h b/include/linux/mman.h index 92dc257251e4..0ba8a7e8b90a 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -1,27 +1,81 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_MMAN_H #define _LINUX_MMAN_H +#include <linux/fs.h> #include <linux/mm.h> #include <linux/percpu_counter.h> #include <linux/atomic.h> #include <uapi/linux/mman.h> +/* + * Arrange for legacy / undefined architecture specific flags to be + * ignored by mmap handling code. + */ +#ifndef MAP_32BIT +#define MAP_32BIT 0 +#endif +#ifndef MAP_ABOVE4G +#define MAP_ABOVE4G 0 +#endif +#ifndef MAP_HUGE_2MB +#define MAP_HUGE_2MB 0 +#endif +#ifndef MAP_HUGE_1GB +#define MAP_HUGE_1GB 0 +#endif +#ifndef MAP_UNINITIALIZED +#define MAP_UNINITIALIZED 0 +#endif +#ifndef MAP_SYNC +#define MAP_SYNC 0 +#endif + +/* + * The historical set of flags that all mmap implementations implicitly + * support when a ->mmap_validate() op is not provided in file_operations. + * + * MAP_EXECUTABLE and MAP_DENYWRITE are completely ignored throughout the + * kernel. + */ +#define LEGACY_MAP_MASK (MAP_SHARED \ + | MAP_PRIVATE \ + | MAP_FIXED \ + | MAP_ANONYMOUS \ + | MAP_DENYWRITE \ + | MAP_EXECUTABLE \ + | MAP_UNINITIALIZED \ + | MAP_GROWSDOWN \ + | MAP_LOCKED \ + | MAP_NORESERVE \ + | MAP_POPULATE \ + | MAP_NONBLOCK \ + | MAP_STACK \ + | MAP_HUGETLB \ + | MAP_32BIT \ + | MAP_ABOVE4G \ + | MAP_HUGE_2MB \ + | MAP_HUGE_1GB) + extern int sysctl_overcommit_memory; -extern int sysctl_overcommit_ratio; extern struct percpu_counter vm_committed_as; #ifdef CONFIG_SMP extern s32 vm_committed_as_batch; +extern void mm_compute_batch(int overcommit_policy); #else #define vm_committed_as_batch 0 +static inline void mm_compute_batch(int overcommit_policy) +{ +} #endif unsigned long vm_memory_committed(void); static inline void vm_acct_memory(long pages) { - __percpu_counter_add(&vm_committed_as, pages, vm_committed_as_batch); + percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch); } static inline void vm_unacct_memory(long pages) @@ -30,15 +84,16 @@ static inline void vm_unacct_memory(long pages) } /* - * Allow architectures to handle additional protection bits + * Allow architectures to handle additional protection and flag bits. The + * overriding macros must be defined in the arch-specific asm/mman.h file. */ #ifndef arch_calc_vm_prot_bits -#define arch_calc_vm_prot_bits(prot) 0 +#define arch_calc_vm_prot_bits(prot, pkey) 0 #endif -#ifndef arch_vm_get_page_prot -#define arch_vm_get_page_prot(vm_flags) __pgprot(0) +#ifndef arch_calc_vm_flag_bits +#define arch_calc_vm_flag_bits(file, flags) 0 #endif #ifndef arch_validate_prot @@ -48,13 +103,26 @@ static inline void vm_unacct_memory(long pages) * * Returns true if the prot flags are valid */ -static inline int arch_validate_prot(unsigned long prot) +static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) { return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0; } #define arch_validate_prot arch_validate_prot #endif +#ifndef arch_validate_flags +/* + * This is called from mmap() and mprotect() with the updated vma->vm_flags. + * + * Returns true if the VM_* flags are valid. + */ +static inline bool arch_validate_flags(unsigned long flags) +{ + return true; +} +#define arch_validate_flags arch_validate_flags +#endif + /* * Optimisation macro. It is equivalent to: * (x & bit1) ? bit2 : 0 @@ -62,29 +130,93 @@ static inline int arch_validate_prot(unsigned long prot) * ("bit1" and "bit2" must be single bits) */ #define _calc_vm_trans(x, bit1, bit2) \ + ((!(bit1) || !(bit2)) ? 0 : \ ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \ - : ((x) & (bit1)) / ((bit1) / (bit2))) + : ((x) & (bit1)) / ((bit1) / (bit2)))) /* * Combine the mmap "prot" argument into "vm_flags" used internally. */ -static inline unsigned long -calc_vm_prot_bits(unsigned long prot) +static inline vm_flags_t +calc_vm_prot_bits(unsigned long prot, unsigned long pkey) { return _calc_vm_trans(prot, PROT_READ, VM_READ ) | _calc_vm_trans(prot, PROT_WRITE, VM_WRITE) | _calc_vm_trans(prot, PROT_EXEC, VM_EXEC) | - arch_calc_vm_prot_bits(prot); + arch_calc_vm_prot_bits(prot, pkey); } /* * Combine the mmap "flags" argument into "vm_flags" used internally. */ -static inline unsigned long -calc_vm_flag_bits(unsigned long flags) +static inline vm_flags_t +calc_vm_flag_bits(struct file *file, unsigned long flags) { return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | - _calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) | - _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ); + _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | + _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + _calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) | +#endif + arch_calc_vm_flag_bits(file, flags); } + +unsigned long vm_commit_limit(void); + +#ifndef arch_memory_deny_write_exec_supported +static inline bool arch_memory_deny_write_exec_supported(void) +{ + return true; +} +#define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported +#endif + +/* + * Denies creating a writable executable mapping or gaining executable permissions. + * + * This denies the following: + * + * a) mmap(PROT_WRITE | PROT_EXEC) + * + * b) mmap(PROT_WRITE) + * mprotect(PROT_EXEC) + * + * c) mmap(PROT_WRITE) + * mprotect(PROT_READ) + * mprotect(PROT_EXEC) + * + * But allows the following: + * + * d) mmap(PROT_READ | PROT_EXEC) + * mmap(PROT_READ | PROT_EXEC | PROT_BTI) + * + * This is only applicable if the user has set the Memory-Deny-Write-Execute + * (MDWE) protection mask for the current process. + * + * @old specifies the VMA flags the VMA originally possessed, and @new the ones + * we propose to set. + * + * Return: false if proposed change is OK, true if not ok and should be denied. + */ +static inline bool map_deny_write_exec(unsigned long old, unsigned long new) +{ + /* If MDWE is disabled, we have nothing to deny. */ + if (!mm_flags_test(MMF_HAS_MDWE, current->mm)) + return false; + + /* If the new VMA is not executable, we have nothing to deny. */ + if (!(new & VM_EXEC)) + return false; + + /* Under MDWE we do not accept newly writably executable VMAs... */ + if (new & VM_WRITE) + return true; + + /* ...nor previously non-executable VMAs becoming executable. */ + if (!(old & VM_EXEC)) + return true; + + return false; +} + #endif /* _LINUX_MMAN_H */ |