Hi all,
Today's linux-next merge of the tip tree got a conflict in
arch/x86/kernel/ptrace.c between commit 91397401bb50 ("ARCH: AUDIT:
audit_syscall_entry() should not require the arch") from the audit tree
and commit e0ffbaabc46d ("x86: Split syscall_trace_enter into two
phases") from the tip tree.
I fixed it up (see below - there is more cleanup possible since
do_audit_syscall_entry() no longer needs its "arch" argument) and can
carry the fix as necessary (no action is required).
--
Cheers,
Stephen Rothwell s...@canb.auug.org.au
diff --cc arch/x86/kernel/ptrace.c
index eb1c87f0b03b,29576c244699..000000000000
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@@ -1441,24 -1441,126 +1441,126 @@@ void send_sigtrap(struct task_struct *t
force_sig_info(SIGTRAP, &info, tsk);
}
-
- #ifdef CONFIG_X86_32
- # define IS_IA32 1
- #elif defined CONFIG_IA32_EMULATION
- # define IS_IA32 is_compat_task()
- #else
- # define IS_IA32 0
+ static void do_audit_syscall_entry(struct pt_regs *regs, u32 arch)
+ {
+ #ifdef CONFIG_X86_64
+ if (arch == AUDIT_ARCH_X86_64) {
- audit_syscall_entry(arch, regs->orig_ax, regs->di,
++ audit_syscall_entry(regs->orig_ax, regs->di,
+ regs->si, regs->dx, regs->r10);
+ } else
#endif
+ {
- audit_syscall_entry(arch, regs->orig_ax, regs->bx,
++ audit_syscall_entry(regs->orig_ax, regs->bx,
+ regs->cx, regs->dx, regs->si);
+ }
+ }
/*
- * We must return the syscall number to actually look up in the table.
- * This can be -1L to skip running any syscall at all.
+ * We can return 0 to resume the syscall or anything else to go to phase
+ * 2. If we resume the syscall, we need to put something appropriate in
+ * regs->orig_ax.
+ *
+ * NB: We don't have full pt_regs here, but regs->orig_ax and regs->ax
+ * are fully functional.
+ *
+ * For phase 2's benefit, our return value is:
+ * 0: resume the syscall
+ * 1: go to phase 2; no seccomp phase 2 needed
+ * anything else: go to phase 2; pass return value to seccomp
*/
- long syscall_trace_enter(struct pt_regs *regs)
+ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
+ {
+ unsigned long ret = 0;
+ u32 work;
+
+ BUG_ON(regs != task_pt_regs(current));
+
+ work = ACCESS_ONCE(current_thread_info()->flags) &
+ _TIF_WORK_SYSCALL_ENTRY;
+
+ /*
+ * If TIF_NOHZ is set, we are required to call user_exit() before
+ * doing anything that could touch RCU.
+ */
+ if (work & _TIF_NOHZ) {
+ user_exit();
+ work &= ~TIF_NOHZ;
+ }
+
+ #ifdef CONFIG_SECCOMP
+ /*
+ * Do seccomp first -- it should minimize exposure of other
+ * code, and keeping seccomp fast is probably more valuable
+ * than the rest of this.
+ */
+ if (work & _TIF_SECCOMP) {
+ struct seccomp_data sd;
+
+ sd.arch = arch;
+ sd.nr = regs->orig_ax;
+ sd.instruction_pointer = regs->ip;
+ #ifdef CONFIG_X86_64
+ if (arch == AUDIT_ARCH_X86_64) {
+ sd.args[0] = regs->di;
+ sd.args[1] = regs->si;
+ sd.args[2] = regs->dx;
+ sd.args[3] = regs->r10;
+ sd.args[4] = regs->r8;
+ sd.args[5] = regs->r9;
+ } else
+ #endif
+ {
+ sd.args[0] = regs->bx;
+ sd.args[1] = regs->cx;
+ sd.args[2] = regs->dx;
+ sd.args[3] = regs->si;
+ sd.args[4] = regs->di;
+ sd.args[5] = regs->bp;
+ }
+
+ BUILD_BUG_ON(SECCOMP_PHASE1_OK != 0);
+ BUILD_BUG_ON(SECCOMP_PHASE1_SKIP != 1);
+
+ ret = seccomp_phase1(&sd);
+ if (ret == SECCOMP_PHASE1_SKIP) {
+ regs->orig_ax = -1;
+ ret = 0;
+ } else if (ret != SECCOMP_PHASE1_OK) {
+ return ret; /* Go directly to phase 2 */
+ }
+
+ work &= ~_TIF_SECCOMP;
+ }
+ #endif
+
+ /* Do our best to finish without phase 2. */
+ if (work == 0)
+ return ret; /* seccomp and/or nohz only (ret == 0 here) */
+
+ #ifdef CONFIG_AUDITSYSCALL
+ if (work == _TIF_SYSCALL_AUDIT) {
+ /*
+ * If there is no more work to be done except auditing,
+ * then audit in phase 1. Phase 2 always audits, so, if
+ * we audit here, then we can't go on to phase 2.
+ */
+ do_audit_syscall_entry(regs, arch);
+ return 0;
+ }
+ #endif
+
+ return 1; /* Something is enabled that we can't handle in phase 1 */
+ }
+
+ /* Returns the syscall nr to run (which should match regs->orig_ax). */
+ long syscall_trace_enter_phase2(struct pt_regs *regs, u32 arch,
+ unsigned long phase1_result)
{
long ret = 0;
+ u32 work = ACCESS_ONCE(current_thread_info()->flags) &
+ _TIF_WORK_SYSCALL_ENTRY;
- user_exit();
+ BUG_ON(regs != task_pt_regs(current));
/*
* If we stepped into a sysenter/syscall insn, it trapped in
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