From: Thomas Gleixner Date: Wed, 19 Aug 2020 19:44:39 +0000 (+0200) Subject: core/entry: Respect syscall number rewrites X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d88d59b64ca35abae208e2781fdb45e69cbed56c;p=linux.git core/entry: Respect syscall number rewrites The transcript of the x86 entry code to the generic version failed to reload the syscall number from ptregs after ptrace and seccomp have run, which both can modify the syscall number in ptregs. It returns the original syscall number instead which is obviously not the right thing to do. Reload the syscall number to fix that. Fixes: 142781e108b1 ("entry: Provide generic syscall entry functionality") Reported-by: Kyle Huey Signed-off-by: Thomas Gleixner Tested-by: Kyle Huey Tested-by: Kees Cook Acked-by: Kees Cook Link: https://lore.kernel.org/r/87blj6ifo8.fsf@nanos.tec.linutronix.de --- diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 9852e0d62d95c..fcae019158cad 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -65,7 +65,8 @@ static long syscall_trace_enter(struct pt_regs *regs, long syscall, syscall_enter_audit(regs, syscall); - return ret ? : syscall; + /* The above might have changed the syscall number */ + return ret ? : syscall_get_nr(current, regs); } noinstr long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)