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-rw-r--r--arch/x86/kernel/entry_64.S48
-rw-r--r--kernel/auditsc.c3
2 files changed, 50 insertions, 1 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index a169225..db7d34a 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -53,6 +53,12 @@
#include <asm/paravirt.h>
#include <asm/ftrace.h>
+/* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */
+#include <linux/elf-em.h>
+#define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
+#define __AUDIT_ARCH_64BIT 0x80000000
+#define __AUDIT_ARCH_LE 0x40000000
+
.code64
#ifdef CONFIG_FTRACE
@@ -351,6 +357,7 @@ ENTRY(system_call_after_swapgs)
GET_THREAD_INFO(%rcx)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx)
jnz tracesys
+system_call_fastpath:
cmpq $__NR_syscall_max,%rax
ja badsys
movq %r10,%rcx
@@ -402,6 +409,10 @@ sysret_careful:
sysret_signal:
TRACE_IRQS_ON
ENABLE_INTERRUPTS(CLBR_NONE)
+#ifdef CONFIG_AUDITSYSCALL
+ bt $TIF_SYSCALL_AUDIT,%edx
+ jc sysret_audit
+#endif
/* edx: work flags (arg3) */
leaq do_notify_resume(%rip),%rax
leaq -ARGOFFSET(%rsp),%rdi # &pt_regs -> arg1
@@ -418,8 +429,45 @@ badsys:
movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
jmp ret_from_sys_call
+#ifdef CONFIG_AUDITSYSCALL
+ /*
+ * Fast path for syscall audit without full syscall trace.
+ * We just call audit_syscall_entry() directly, and then
+ * jump back to the normal fast path.
+ */
+auditsys:
+ movq %r10,%r9 /* 6th arg: 4th syscall arg */
+ movq %rdx,%r8 /* 5th arg: 3rd syscall arg */
+ movq %rsi,%rcx /* 4th arg: 2nd syscall arg */
+ movq %rdi,%rdx /* 3rd arg: 1st syscall arg */
+ movq %rax,%rsi /* 2nd arg: syscall number */
+ movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */
+ call audit_syscall_entry
+ LOAD_ARGS 0 /* reload call-clobbered registers */
+ jmp system_call_fastpath
+
+ /*
+ * Return fast path for syscall audit. Call audit_syscall_exit()
+ * directly and then jump back to the fast path with TIF_SYSCALL_AUDIT
+ * masked off.
+ */
+sysret_audit:
+ movq %rax,%rsi /* second arg, syscall return value */
+ cmpq $0,%rax /* is it < 0? */
+ setl %al /* 1 if so, 0 if not */
+ movzbl %al,%edi /* zero-extend that into %edi */
+ inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */
+ call audit_syscall_exit
+ movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
+ jmp sysret_check
+#endif /* CONFIG_AUDITSYSCALL */
+
/* Do syscall tracing */
tracesys:
+#ifdef CONFIG_AUDITSYSCALL
+ testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%rcx)
+ jz auditsys
+#endif
SAVE_REST
movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
FIXUP_TOP_OF_STACK %rdi
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index c10e7aa..4699950 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1476,7 +1476,8 @@ void audit_syscall_entry(int arch, int major,
struct audit_context *context = tsk->audit_context;
enum audit_state state;
- BUG_ON(!context);
+ if (unlikely(!context))
+ return;
/*
* This happens only on certain architectures that make system
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