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Diffstat (limited to 'mm/mprotect.c')
-rw-r--r--mm/mprotect.c90
1 files changed, 85 insertions, 5 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index ec91dfd3f900..bcdbe62f3e6d 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -23,11 +23,13 @@
#include <linux/mmu_notifier.h>
#include <linux/migrate.h>
#include <linux/perf_event.h>
+#include <linux/pkeys.h>
#include <linux/ksm.h>
#include <linux/pkeys.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include "internal.h"
@@ -353,8 +355,11 @@ fail:
return error;
}
-SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
- unsigned long, prot)
+/*
+ * pkey==-1 when doing a legacy mprotect()
+ */
+static int do_mprotect_pkey(unsigned long start, size_t len,
+ unsigned long prot, int pkey)
{
unsigned long nstart, end, tmp, reqprot;
struct vm_area_struct *vma, *prev;
@@ -383,6 +388,14 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
if (down_write_killable(&current->mm->mmap_sem))
return -EINTR;
+ /*
+ * If userspace did not allocate the pkey, do not let
+ * them use it here.
+ */
+ error = -EINVAL;
+ if ((pkey != -1) && !mm_pkey_is_allocated(current->mm, pkey))
+ goto out;
+
vma = find_vma(current->mm, start);
error = -ENOMEM;
if (!vma)
@@ -409,8 +422,9 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
prev = vma;
for (nstart = start ; ; ) {
+ unsigned long mask_off_old_flags;
unsigned long newflags;
- int pkey = arch_override_mprotect_pkey(vma, prot, -1);
+ int new_vma_pkey;
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
@@ -418,8 +432,17 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
if (rier && (vma->vm_flags & VM_MAYEXEC))
prot |= PROT_EXEC;
- newflags = calc_vm_prot_bits(prot, pkey);
- newflags |= (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
+ /*
+ * Each mprotect() call explicitly passes r/w/x permissions.
+ * If a permission is not passed to mprotect(), it must be
+ * cleared from the VMA.
+ */
+ mask_off_old_flags = VM_READ | VM_WRITE | VM_EXEC |
+ ARCH_VM_PKEY_FLAGS;
+
+ new_vma_pkey = arch_override_mprotect_pkey(vma, prot, pkey);
+ newflags = calc_vm_prot_bits(prot, new_vma_pkey);
+ newflags |= (vma->vm_flags & ~mask_off_old_flags);
/* newflags >> 4 shift VM_MAY% in place of VM_% */
if ((newflags & ~(newflags >> 4)) & (VM_READ | VM_WRITE | VM_EXEC)) {
@@ -455,3 +478,60 @@ out:
up_write(&current->mm->mmap_sem);
return error;
}
+
+SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
+ unsigned long, prot)
+{
+ return do_mprotect_pkey(start, len, prot, -1);
+}
+
+SYSCALL_DEFINE4(pkey_mprotect, unsigned long, start, size_t, len,
+ unsigned long, prot, int, pkey)
+{
+ return do_mprotect_pkey(start, len, prot, pkey);
+}
+
+SYSCALL_DEFINE2(pkey_alloc, unsigned long, flags, unsigned long, init_val)
+{
+ int pkey;
+ int ret;
+
+ /* No flags supported yet. */
+ if (flags)
+ return -EINVAL;
+ /* check for unsupported init values */
+ if (init_val & ~PKEY_ACCESS_MASK)
+ return -EINVAL;
+
+ down_write(&current->mm->mmap_sem);
+ pkey = mm_pkey_alloc(current->mm);
+
+ ret = -ENOSPC;
+ if (pkey == -1)
+ goto out;
+
+ ret = arch_set_user_pkey_access(current, pkey, init_val);
+ if (ret) {
+ mm_pkey_free(current->mm, pkey);
+ goto out;
+ }
+ ret = pkey;
+out:
+ up_write(&current->mm->mmap_sem);
+ return ret;
+}
+
+SYSCALL_DEFINE1(pkey_free, int, pkey)
+{
+ int ret;
+
+ down_write(&current->mm->mmap_sem);
+ ret = mm_pkey_free(current->mm, pkey);
+ up_write(&current->mm->mmap_sem);
+
+ /*
+ * We could provie warnings or errors if any VMA still
+ * has the pkey set here.
+ */
+ return ret;
+}