On Fri, Jan 17, 2025 at 12:02 AM Masami Hiramatsu mhiramat@kernel.org wrote:
On Fri, 17 Jan 2025 02:39:28 +0100 Oleg Nesterov oleg@redhat.com wrote:
On 01/16, Eyal Birger wrote:
Fixes: ff474a78cef5 ("uprobe: Add uretprobe syscall to speed up return probe") Reported-by: Rafael Buchbinder rafi@rbk.io Link: https://lore.kernel.org/lkml/CAHsH6Gs3Eh8DFU0wq58c_LF8A4_+o6z456J7BidmcVY2Aq... Cc: stable@vger.kernel.org
...
@@ -1359,6 +1359,11 @@ int __secure_computing(const struct seccomp_data *sd) this_syscall = sd ? sd->nr : syscall_get_nr(current, current_pt_regs());
+#ifdef CONFIG_X86_64
- if (unlikely(this_syscall == __NR_uretprobe) && !in_ia32_syscall())
return 0;+#endif
Acked-by: Oleg Nesterov oleg@redhat.com
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) { // arch_is_uprobe_syscall check can be replaced by Kconfig, // something like CONFIG_ARCH_URETPROBE_SYSCALL. #ifdef arch_is_uprobe_syscall return arch_is_uprobe_syscall(syscall) #else return false; #endif }and
#define arch_is_uprobe_syscall(syscall) \ (IS_ENABLED(CONFIG_X86_64) && syscall == __NR_uretprobe && !in_ia32_syscall())
Notice it'll need to be enclosed in ifdef CONFIG_X86_64 as __NR_uretprobe isn't defined otherwise so the IS_ENABLED isn't needed.
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.
I like this approach.
Notice it does add a couple of includes that weren't there before: - arch/x86/include/asm/uprobes.h would include asm/unistd.h - seccomp.c would include linux/uprobes.h
So it's a less "trivial" patch... If that's ok I can repost with these changes.
Eyal.