Update Linux to v5.4.148
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz
Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 8eb7193..026ce06 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -241,10 +241,11 @@
void __user **fpstate)
{
/* Default to using normal stack */
+ bool nested_altstack = on_sig_stack(regs->sp);
+ bool entering_altstack = false;
unsigned long math_size = 0;
unsigned long sp = regs->sp;
unsigned long buf_fx = 0;
- int onsigstack = on_sig_stack(sp);
int ret;
/* redzone */
@@ -253,15 +254,23 @@
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
- if (sas_ss_flags(sp) == 0)
+ /*
+ * This checks nested_altstack via sas_ss_flags(). Sensible
+ * programs use SS_AUTODISARM, which disables that check, and
+ * programs that don't use SS_AUTODISARM get compatible.
+ */
+ if (sas_ss_flags(sp) == 0) {
sp = current->sas_ss_sp + current->sas_ss_size;
+ entering_altstack = true;
+ }
} else if (IS_ENABLED(CONFIG_X86_32) &&
- !onsigstack &&
+ !nested_altstack &&
regs->ss != __USER_DS &&
!(ka->sa.sa_flags & SA_RESTORER) &&
ka->sa.sa_restorer) {
/* This is the legacy signal stack switching. */
sp = (unsigned long) ka->sa.sa_restorer;
+ entering_altstack = true;
}
sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
@@ -274,8 +283,15 @@
* If we are on the alternate signal stack and would overflow it, don't.
* Return an always-bogus address instead so we will die with SIGSEGV.
*/
- if (onsigstack && !likely(on_sig_stack(sp)))
+ if (unlikely((nested_altstack || entering_altstack) &&
+ !__on_sig_stack(sp))) {
+
+ if (show_unhandled_signals && printk_ratelimit())
+ pr_info("%s[%d] overflowed sigaltstack\n",
+ current->comm, task_pid_nr(current));
+
return (void __user *)-1L;
+ }
/* save i387 and extended state */
ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size);
@@ -770,30 +786,8 @@
static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs)
{
- /*
- * This function is fundamentally broken as currently
- * implemented.
- *
- * The idea is that we want to trigger a call to the
- * restart_block() syscall and that we want in_ia32_syscall(),
- * in_x32_syscall(), etc. to match whatever they were in the
- * syscall being restarted. We assume that the syscall
- * instruction at (regs->ip - 2) matches whatever syscall
- * instruction we used to enter in the first place.
- *
- * The problem is that we can get here when ptrace pokes
- * syscall-like values into regs even if we're not in a syscall
- * at all.
- *
- * For now, we maintain historical behavior and guess based on
- * stored state. We could do better by saving the actual
- * syscall arch in restart_block or (with caveats on x32) by
- * checking if regs->ip points to 'int $0x80'. The current
- * behavior is incorrect if a tracer has a different bitness
- * than the tracee.
- */
#ifdef CONFIG_IA32_EMULATION
- if (current_thread_info()->status & (TS_COMPAT|TS_I386_REGS_POKED))
+ if (current_thread_info()->status & TS_COMPAT_RESTART)
return __NR_ia32_restart_syscall;
#endif
#ifdef CONFIG_X86_X32_ABI