aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/mm
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/mm')
-rw-r--r--arch/x86/mm/extable.c24
-rw-r--r--arch/x86/mm/fault.c47
-rw-r--r--arch/x86/mm/mem_encrypt.c2
-rw-r--r--arch/x86/mm/pkeys.c3
-rw-r--r--arch/x86/mm/tlb.c2
5 files changed, 52 insertions, 26 deletions
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index c076f710de4c..c3521e2be396 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -2,6 +2,7 @@
#include <linux/uaccess.h>
#include <linux/sched/debug.h>
+#include <asm/fpu/internal.h>
#include <asm/traps.h>
#include <asm/kdebug.h>
@@ -78,6 +79,29 @@ bool ex_handler_refcount(const struct exception_table_entry *fixup,
}
EXPORT_SYMBOL_GPL(ex_handler_refcount);
+/*
+ * Handler for when we fail to restore a task's FPU state. We should never get
+ * here because the FPU state of a task using the FPU (task->thread.fpu.state)
+ * should always be valid. However, past bugs have allowed userspace to set
+ * reserved bits in the XSAVE area using PTRACE_SETREGSET or sys_rt_sigreturn().
+ * These caused XRSTOR to fail when switching to the task, leaking the FPU
+ * registers of the task previously executing on the CPU. Mitigate this class
+ * of vulnerability by restoring from the initial state (essentially, zeroing
+ * out all the FPU registers) if we can't restore from the task's FPU state.
+ */
+bool ex_handler_fprestore(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, int trapnr)
+{
+ regs->ip = ex_fixup_addr(fixup);
+
+ WARN_ONCE(1, "Bad FPU state detected at %pB, reinitializing FPU registers.",
+ (void *)instruction_pointer(regs));
+
+ __copy_kernel_to_fpregs(&init_fpstate, -1);
+ return true;
+}
+EXPORT_SYMBOL_GPL(ex_handler_fprestore);
+
bool ex_handler_ext(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 39567b5c33da..e2baeaa053a5 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -192,8 +192,7 @@ is_prefetch(struct pt_regs *regs, unsigned long error_code, unsigned long addr)
* 6. T1 : reaches here, sees vma_pkey(vma)=5, when we really
* faulted on a pte with its pkey=4.
*/
-static void fill_sig_info_pkey(int si_code, siginfo_t *info,
- struct vm_area_struct *vma)
+static void fill_sig_info_pkey(int si_code, siginfo_t *info, u32 *pkey)
{
/* This is effectively an #ifdef */
if (!boot_cpu_has(X86_FEATURE_OSPKE))
@@ -209,7 +208,7 @@ static void fill_sig_info_pkey(int si_code, siginfo_t *info,
* valid VMA, so we should never reach this without a
* valid VMA.
*/
- if (!vma) {
+ if (!pkey) {
WARN_ONCE(1, "PKU fault with no VMA passed in");
info->si_pkey = 0;
return;
@@ -219,13 +218,12 @@ static void fill_sig_info_pkey(int si_code, siginfo_t *info,
* absolutely guranteed to be 100% accurate because of
* the race explained above.
*/
- info->si_pkey = vma_pkey(vma);
+ info->si_pkey = *pkey;
}
static void
force_sig_info_fault(int si_signo, int si_code, unsigned long address,
- struct task_struct *tsk, struct vm_area_struct *vma,
- int fault)
+ struct task_struct *tsk, u32 *pkey, int fault)
{
unsigned lsb = 0;
siginfo_t info;
@@ -240,7 +238,7 @@ force_sig_info_fault(int si_signo, int si_code, unsigned long address,
lsb = PAGE_SHIFT;
info.si_addr_lsb = lsb;
- fill_sig_info_pkey(si_code, &info, vma);
+ fill_sig_info_pkey(si_code, &info, pkey);
force_sig_info(si_signo, &info, tsk);
}
@@ -762,8 +760,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
struct task_struct *tsk = current;
unsigned long flags;
int sig;
- /* No context means no VMA to pass down */
- struct vm_area_struct *vma = NULL;
/* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs, X86_TRAP_PF)) {
@@ -788,7 +784,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
/* XXX: hwpoison faults will set the wrong code. */
force_sig_info_fault(signal, si_code, address,
- tsk, vma, 0);
+ tsk, NULL, 0);
}
/*
@@ -896,8 +892,7 @@ show_signal_msg(struct pt_regs *regs, unsigned long error_code,
static void
__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma,
- int si_code)
+ unsigned long address, u32 *pkey, int si_code)
{
struct task_struct *tsk = current;
@@ -945,7 +940,7 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = X86_TRAP_PF;
- force_sig_info_fault(SIGSEGV, si_code, address, tsk, vma, 0);
+ force_sig_info_fault(SIGSEGV, si_code, address, tsk, pkey, 0);
return;
}
@@ -958,9 +953,9 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
static noinline void
bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma)
+ unsigned long address, u32 *pkey)
{
- __bad_area_nosemaphore(regs, error_code, address, vma, SEGV_MAPERR);
+ __bad_area_nosemaphore(regs, error_code, address, pkey, SEGV_MAPERR);
}
static void
@@ -968,6 +963,10 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
unsigned long address, struct vm_area_struct *vma, int si_code)
{
struct mm_struct *mm = current->mm;
+ u32 pkey;
+
+ if (vma)
+ pkey = vma_pkey(vma);
/*
* Something tried to access memory that isn't in our memory map..
@@ -975,7 +974,8 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
*/
up_read(&mm->mmap_sem);
- __bad_area_nosemaphore(regs, error_code, address, vma, si_code);
+ __bad_area_nosemaphore(regs, error_code, address,
+ (vma) ? &pkey : NULL, si_code);
}
static noinline void
@@ -1018,7 +1018,7 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
static void
do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
- struct vm_area_struct *vma, unsigned int fault)
+ u32 *pkey, unsigned int fault)
{
struct task_struct *tsk = current;
int code = BUS_ADRERR;
@@ -1045,13 +1045,12 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
code = BUS_MCEERR_AR;
}
#endif
- force_sig_info_fault(SIGBUS, code, address, tsk, vma, fault);
+ force_sig_info_fault(SIGBUS, code, address, tsk, pkey, fault);
}
static noinline void
mm_fault_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma,
- unsigned int fault)
+ unsigned long address, u32 *pkey, unsigned int fault)
{
if (fatal_signal_pending(current) && !(error_code & PF_USER)) {
no_context(regs, error_code, address, 0, 0);
@@ -1075,9 +1074,9 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
} else {
if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
VM_FAULT_HWPOISON_LARGE))
- do_sigbus(regs, error_code, address, vma, fault);
+ do_sigbus(regs, error_code, address, pkey, fault);
else if (fault & VM_FAULT_SIGSEGV)
- bad_area_nosemaphore(regs, error_code, address, vma);
+ bad_area_nosemaphore(regs, error_code, address, pkey);
else
BUG();
}
@@ -1267,6 +1266,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
struct mm_struct *mm;
int fault, major = 0;
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+ u32 pkey;
tsk = current;
mm = tsk->mm;
@@ -1467,9 +1467,10 @@ good_area:
return;
}
+ pkey = vma_pkey(vma);
up_read(&mm->mmap_sem);
if (unlikely(fault & VM_FAULT_ERROR)) {
- mm_fault_error(regs, error_code, address, vma, fault);
+ mm_fault_error(regs, error_code, address, &pkey, fault);
return;
}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 3fcc8e01683b..16c5f37933a2 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -10,6 +10,8 @@
* published by the Free Software Foundation.
*/
+#define DISABLE_BRANCH_PROFILING
+
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/mm.h>
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 2dab69a706ec..d7bc0eea20a5 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -18,7 +18,6 @@
#include <asm/cpufeature.h> /* boot_cpu_has, ... */
#include <asm/mmu_context.h> /* vma_pkey() */
-#include <asm/fpu/internal.h> /* fpregs_active() */
int __execute_only_pkey(struct mm_struct *mm)
{
@@ -45,7 +44,7 @@ int __execute_only_pkey(struct mm_struct *mm)
*/
preempt_disable();
if (!need_to_set_mm_pkey &&
- fpregs_active() &&
+ current->thread.fpu.initialized &&
!__pkru_allows_read(read_pkru(), execute_only_pkey)) {
preempt_enable();
return execute_only_pkey;
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 93fe97cce581..49d9778376d7 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -191,7 +191,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next,
* mapped in the new pgd, we'll double-fault. Forcibly
* map it.
*/
- unsigned int index = pgd_index(current_stack_pointer());
+ unsigned int index = pgd_index(current_stack_pointer);
pgd_t *pgd = next->pgd + index;
if (unlikely(pgd_none(*pgd)))
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.