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-rw-r--r--arch/x86/include/asm/mmu_context.h21
-rw-r--r--arch/x86/kernel/ldt.c18
-rw-r--r--tools/testing/selftests/x86/ldt_gdt.c9
3 files changed, 22 insertions, 26 deletions
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 4fdbe5efe535..5e25423bf9bb 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -57,11 +57,17 @@ struct ldt_struct {
/*
* Used for LDT copy/destruction.
*/
-int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm);
+static inline void init_new_context_ldt(struct mm_struct *mm)
+{
+ mm->context.ldt = NULL;
+ init_rwsem(&mm->context.ldt_usr_sem);
+}
+int ldt_dup_context(struct mm_struct *oldmm, struct mm_struct *mm);
void destroy_context_ldt(struct mm_struct *mm);
#else /* CONFIG_MODIFY_LDT_SYSCALL */
-static inline int init_new_context_ldt(struct task_struct *tsk,
- struct mm_struct *mm)
+static inline void init_new_context_ldt(struct mm_struct *mm) { }
+static inline int ldt_dup_context(struct mm_struct *oldmm,
+ struct mm_struct *mm)
{
return 0;
}
@@ -137,15 +143,16 @@ static inline int init_new_context(struct task_struct *tsk,
mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id);
atomic64_set(&mm->context.tlb_gen, 0);
- #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
if (cpu_feature_enabled(X86_FEATURE_OSPKE)) {
/* pkey 0 is the default and always allocated */
mm->context.pkey_allocation_map = 0x1;
/* -1 means unallocated or invalid */
mm->context.execute_only_pkey = -1;
}
- #endif
- return init_new_context_ldt(tsk, mm);
+#endif
+ init_new_context_ldt(mm);
+ return 0;
}
static inline void destroy_context(struct mm_struct *mm)
{
@@ -181,7 +188,7 @@ do { \
static inline int arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
{
paravirt_arch_dup_mmap(oldmm, mm);
- return 0;
+ return ldt_dup_context(oldmm, mm);
}
static inline void arch_exit_mmap(struct mm_struct *mm)
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 1600aebc1ec7..a6b5d62f45a7 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -131,28 +131,20 @@ static void free_ldt_struct(struct ldt_struct *ldt)
}
/*
- * we do not have to muck with descriptors here, that is
- * done in switch_mm() as needed.
+ * Called on fork from arch_dup_mmap(). Just copy the current LDT state,
+ * the new task is not running, so nothing can be installed.
*/
-int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm)
+int ldt_dup_context(struct mm_struct *old_mm, struct mm_struct *mm)
{
struct ldt_struct *new_ldt;
- struct mm_struct *old_mm;
int retval = 0;
- init_rwsem(&mm->context.ldt_usr_sem);
-
- old_mm = current->mm;
- if (!old_mm) {
- mm->context.ldt = NULL;
+ if (!old_mm)
return 0;
- }
mutex_lock(&old_mm->context.lock);
- if (!old_mm->context.ldt) {
- mm->context.ldt = NULL;
+ if (!old_mm->context.ldt)
goto out_unlock;
- }
new_ldt = alloc_ldt_struct(old_mm->context.ldt->nr_entries);
if (!new_ldt) {
diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c
index 66e5ce5b91f0..0304ffb714f2 100644
--- a/tools/testing/selftests/x86/ldt_gdt.c
+++ b/tools/testing/selftests/x86/ldt_gdt.c
@@ -627,13 +627,10 @@ static void do_multicpu_tests(void)
static int finish_exec_test(void)
{
/*
- * In a sensible world, this would be check_invalid_segment(0, 1);
- * For better or for worse, though, the LDT is inherited across exec.
- * We can probably change this safely, but for now we test it.
+ * Older kernel versions did inherit the LDT on exec() which is
+ * wrong because exec() starts from a clean state.
*/
- check_valid_segment(0, 1,
- AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB,
- 42, true);
+ check_invalid_segment(0, 1);
return nerrs ? 1 : 0;
}