On Fri, Jan 17, 2025 at 6:10 AM Oleg Nesterov oleg@redhat.com wrote:
On 01/17, Masami Hiramatsu wrote:
On Fri, 17 Jan 2025 02:39:28 +0100 Oleg Nesterov oleg@redhat.com wrote:
A note for the seccomp maintainers...
I don't know what do you think, but I agree in advance that the very fact this patch adds "#ifdef CONFIG_X86_64" into __secure_computing() doesn't look nice.
Indeed. in_ia32_syscall() depends arch/x86 too. We can add an inline function like;
static inline bool is_uprobe_syscall(int syscall) {We can, and this is what I tried to suggest from the very beginning. But I agree with Eyal who decided to send the most trivial fix for -stable, we can add the helper later.
I don't think it should live in uprobes.h and I'd prefer something like arch_seccomp_ignored(int) but I won't insist.
yep, I think this is the way, keeping it as a general category. Should we also put rt_sigreturn there explicitly as well? Also, wouldn't it be better to have it as a non-arch-specific function for something like rt_sigreturn where defining it per each arch is cumbersome, and have the default implementation also call into an arch-specific function?
// arch_is_uprobe_syscall check can be replaced by Kconfig, // something like CONFIG_ARCH_URETPROBE_SYSCALL.Or sysctl or both. This is another issue.
#define arch_is_uprobe_syscall(syscall) \ (IS_ENABLED(CONFIG_X86_64) && syscall == __NR_uretprobe && !in_ia32_syscall())This won't compile if IS_ENABLED(CONFIG_X86_64) == false, __NR_uretprobe will be undefined.
The problem is that we need a simple patch for -stable which fixes the real problem. We can cleanup this logic later, I think.
Hmm, at least we should make it is_uprobe_syscall() in uprobes.h so that do not pollute the seccomp subsystem with #ifdef.
See above. But I won't insist.
Oleg.