From: Greg Kroah-Hartman gregkh@linuxfoundation.org
From: Andy Lutomirski luto@kernel.org
commit 5d5675df792ff67e74a500c4c94db0f99e6a10ef upstream.
On a 32-bit fast syscall that fails to read its arguments from user memory, the kernel currently does syscall exit work but not syscall entry work. This confuses audit and ptrace. For example:
$ ./tools/testing/selftests/x86/syscall_arg_fault_32 ... strace: pid 264258: entering, ptrace_syscall_info.op == 2 ...
This is a minimal fix intended for ease of backporting. A more complete cleanup is coming.
Fixes: 0b085e68f407 ("x86/entry: Consolidate 32/64 bit syscall entry") Signed-off-by: Andy Lutomirski luto@kernel.org Signed-off-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Borislav Petkov bp@suse.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/8c82296ddf803b91f8d1e5eac89e5803ba54ab0e.161488467... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/entry/common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -128,7 +128,8 @@ static noinstr bool __do_fast_syscall_32 regs->ax = -EFAULT;
instrumentation_end(); - syscall_exit_to_user_mode(regs); + local_irq_disable(); + irqentry_exit_to_user_mode(regs); return false; }