diff options
| -rw-r--r-- | arch/Kconfig | 7 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/elf.h | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/sys_x86_64.c | 23 | ||||
| -rw-r--r-- | arch/x86/mm/mmap.c | 47 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 5 |
6 files changed, 69 insertions, 17 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index cd211a14a88f..c4d6833aacd9 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -700,6 +700,13 @@ config ARCH_MMAP_RND_COMPAT_BITS This value can be changed after boot using the /proc/sys/vm/mmap_rnd_compat_bits tunable +config HAVE_ARCH_COMPAT_MMAP_BASES + bool + help + This allows 64bit applications to invoke 32-bit mmap() syscall + and vice-versa 32-bit applications to call 64-bit mmap(). + Required for applications doing different bitness syscalls. + config HAVE_COPY_THREAD_TLS bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index cc98d5a294ee..2bab9d093b51 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -106,6 +106,7 @@ config X86 select HAVE_ARCH_KMEMCHECK select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT + select HAVE_ARCH_COMPAT_MMAP_BASES if MMU && COMPAT select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_ARCH_TRANSPARENT_HUGEPAGE diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index b908141cf0c4..ac5be5ba8527 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -303,6 +303,9 @@ static inline int mmap_is_ia32(void) test_thread_flag(TIF_ADDR32)); } +extern unsigned long tasksize_32bit(void); +extern unsigned long tasksize_64bit(void); + #ifdef CONFIG_X86_32 #define __STACK_RND_MASK(is32bit) (0x7ff) diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index 50215a4b9347..c54817baabc7 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -17,6 +17,8 @@ #include <linux/uaccess.h> #include <linux/elf.h> +#include <asm/elf.h> +#include <asm/compat.h> #include <asm/ia32.h> #include <asm/syscalls.h> @@ -98,6 +100,18 @@ out: return error; } +static unsigned long get_mmap_base(int is_legacy) +{ + struct mm_struct *mm = current->mm; + +#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES + if (in_compat_syscall()) + return is_legacy ? mm->mmap_compat_legacy_base + : mm->mmap_compat_base; +#endif + return is_legacy ? mm->mmap_legacy_base : mm->mmap_base; +} + static void find_start_end(unsigned long flags, unsigned long *begin, unsigned long *end) { @@ -114,10 +128,11 @@ static void find_start_end(unsigned long flags, unsigned long *begin, if (current->flags & PF_RANDOMIZE) { *begin = randomize_page(*begin, 0x02000000); } - } else { - *begin = current->mm->mmap_legacy_base; - *end = TASK_SIZE; + return; } + + *begin = get_mmap_base(1); + *end = in_compat_syscall() ? tasksize_32bit() : tasksize_64bit(); } unsigned long @@ -191,7 +206,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, info.flags = VM_UNMAPPED_AREA_TOPDOWN; info.length = len; info.low_limit = PAGE_SIZE; - info.high_limit = mm->mmap_base; + info.high_limit = get_mmap_base(0); info.align_mask = 0; info.align_offset = pgoff << PAGE_SHIFT; if (filp) { diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index 1e9cb945dca1..529ab79800af 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -36,11 +36,16 @@ struct va_alignment __read_mostly va_align = { .flags = -1, }; -static inline unsigned long tasksize_32bit(void) +unsigned long tasksize_32bit(void) { return IA32_PAGE_OFFSET; } +unsigned long tasksize_64bit(void) +{ + return TASK_SIZE_MAX; +} + static unsigned long stack_maxrandom_size(unsigned long task_size) { unsigned long max = 0; @@ -81,6 +86,8 @@ static unsigned long arch_rnd(unsigned int rndbits) unsigned long arch_mmap_rnd(void) { + if (!(current->flags & PF_RANDOMIZE)) + return 0; return arch_rnd(mmap_is_ia32() ? mmap32_rnd_bits : mmap64_rnd_bits); } @@ -114,22 +121,36 @@ static unsigned long mmap_legacy_base(unsigned long rnd, * This function, called very early during the creation of a new * process VM image, sets up which VM layout function to use: */ -void arch_pick_mmap_layout(struct mm_struct *mm) +static void arch_pick_mmap_base(unsigned long *base, unsigned long *legacy_base, + unsigned long random_factor, unsigned long task_size) { - unsigned long random_factor = 0UL; - - if (current->flags & PF_RANDOMIZE) - random_factor = arch_mmap_rnd(); - - mm->mmap_legacy_base = mmap_legacy_base(random_factor, TASK_SIZE); + *legacy_base = mmap_legacy_base(random_factor, task_size); + if (mmap_is_legacy()) + *base = *legacy_base; + else + *base = mmap_base(random_factor, task_size); +} - if (mmap_is_legacy()) { - mm->mmap_base = mm->mmap_legacy_base; +void arch_pick_mmap_layout(struct mm_struct *mm) +{ + if (mmap_is_legacy()) mm->get_unmapped_area = arch_get_unmapped_area; - } else { - mm->mmap_base = mmap_base(random_factor, TASK_SIZE); + else mm->get_unmapped_area = arch_get_unmapped_area_topdown; - } + + arch_pick_mmap_base(&mm->mmap_base, &mm->mmap_legacy_base, + arch_rnd(mmap64_rnd_bits), tasksize_64bit()); + +#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES + /* + * The mmap syscall mapping base decision depends solely on the + * syscall type (64-bit or compat). This applies for 64bit + * applications and 32bit applications. The 64bit syscall uses + * mmap_base, the compat syscall uses mmap_compat_base. + */ + arch_pick_mmap_base(&mm->mmap_compat_base, &mm->mmap_compat_legacy_base, + arch_rnd(mmap32_rnd_bits), tasksize_32bit()); +#endif } const char *arch_vma_name(struct vm_area_struct *vma) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index f60f45fe226f..45cdb27791a3 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -367,6 +367,11 @@ struct mm_struct { #endif unsigned long mmap_base; /* base of mmap area */ unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */ +#ifdef CONFIG_HAVE_ARCH_COMPAT_MMAP_BASES + /* Base adresses for compatible mmap() */ + unsigned long mmap_compat_base; + unsigned long mmap_compat_legacy_base; +#endif unsigned long task_size; /* size of task vm space */ unsigned long highest_vm_end; /* highest vma end address */ pgd_t * pgd; |