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-rw-r--r--arch/Kconfig7
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/include/asm/elf.h3
-rw-r--r--arch/x86/kernel/sys_x86_64.c23
-rw-r--r--arch/x86/mm/mmap.c47
-rw-r--r--include/linux/mm_types.h5
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;