audit: Migrate to use SYSCALL_WORK flag

On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SYSCALL_AUDIT, use it in the generic entry code and
convert the code which uses the TIF specific helper functions to use the
new *_syscall_work() helpers which either resolve to the new mode for users
of the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-9-krisman@collabora.com

diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index ed94e5658d0c127c9a6a84dd08e9737cf6a58cd9..524218ae3825640497d76acec1dcec55dd6db296 100644 (file)
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -43,9 +43,9 @@ int syscall_get_nr(struct task_struct *task, struct pt_regs *regs);
  * @regs:      task_pt_regs() of @task
  *
  * It's only valid to call this when @task is stopped for system
- * call exit tracing (due to %SYSCALL_WORK_SYSCALL_TRACE or TIF_SYSCALL_AUDIT),
- * after tracehook_report_syscall_entry() returned nonzero to prevent
- * the system call from taking place.
+ * call exit tracing (due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT), after tracehook_report_syscall_entry()
+ * returned nonzero to prevent the system call from taking place.
  *
  * This rolls back the register state in @regs so it's as if the
  * system call instruction was a no-op.  The registers containing
@@ -63,7 +63,8 @@ void syscall_rollback(struct task_struct *task, struct pt_regs *regs);
  * Returns 0 if the system call succeeded, or -ERRORCODE if it failed.
  *
  * It's only valid to call this when @task is stopped for tracing on exit
- * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
+ * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT.
  */
 long syscall_get_error(struct task_struct *task, struct pt_regs *regs);
 
@@ -76,7 +77,8 @@ long syscall_get_error(struct task_struct *task, struct pt_regs *regs);
  * This value is meaningless if syscall_get_error() returned nonzero.
  *
  * It's only valid to call this when @task is stopped for tracing on exit
- * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
+ * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT.
  */
 long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs);
 
@@ -93,7 +95,8 @@ long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs);
  * code; the user sees a failed system call with this errno code.
  *
  * It's only valid to call this when @task is stopped for tracing on exit
- * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
+ * from a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT.
  */
 void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
                              int error, long val);
@@ -108,7 +111,8 @@ void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
 *  @args[0], and so on.
  *
  * It's only valid to call this when @task is stopped for tracing on
- * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
+ * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT.
  */
 void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
                           unsigned long *args);
@@ -123,7 +127,8 @@ void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
  * The first argument gets value @args[0], and so on.
  *
  * It's only valid to call this when @task is stopped for tracing on
- * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or %TIF_SYSCALL_AUDIT.
+ * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT.
  */
 void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
                           const unsigned long *args);
@@ -135,7 +140,7 @@ void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
  * Returns the AUDIT_ARCH_* based on the system call convention in use.
  *
  * It's only valid to call this when @task is stopped on entry to a system
- * call, due to %SYSCALL_WORK_SYSCALL_TRACE, %TIF_SYSCALL_AUDIT, or
+ * call, due to %SYSCALL_WORK_SYSCALL_TRACE, %SYSCALL_WORK_SYSCALL_AUDIT, or
  * %SYSCALL_WORK_SECCOMP.
  *
  * Architectures which permit CONFIG_HAVE_ARCH_SECCOMP_FILTER must

diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index b30f82bed92b09022180617ce59e855efb367283..d7b96f42817fb05edb54f50330b1d87511205c2a 100644 (file)
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -13,10 +13,6 @@
  * Define dummy _TIF work flags if not defined by the architecture or for
  * disabled functionality.
  */
-#ifndef _TIF_SYSCALL_AUDIT
-# define _TIF_SYSCALL_AUDIT            (0)
-#endif
-
 #ifndef _TIF_PATCH_PENDING
 # define _TIF_PATCH_PENDING            (0)
 #endif
@@ -36,9 +32,7 @@
 # define ARCH_SYSCALL_ENTER_WORK       (0)
 #endif
 
-#define SYSCALL_ENTER_WORK                                             \
-       (_TIF_SYSCALL_AUDIT  |                                          \
-        ARCH_SYSCALL_ENTER_WORK)
+#define SYSCALL_ENTER_WORK ARCH_SYSCALL_ENTER_WORK
 
 /*
  * TIF flags handled in syscall_exit_to_user_mode()
@@ -47,16 +41,16 @@
 # define ARCH_SYSCALL_EXIT_WORK                (0)
 #endif
 
-#define SYSCALL_EXIT_WORK                                              \
-       (_TIF_SYSCALL_AUDIT |                                           \
-        ARCH_SYSCALL_EXIT_WORK)
+#define SYSCALL_EXIT_WORK ARCH_SYSCALL_EXIT_WORK
 
 #define SYSCALL_WORK_ENTER     (SYSCALL_WORK_SECCOMP |                 \
                                 SYSCALL_WORK_SYSCALL_TRACEPOINT |      \
                                 SYSCALL_WORK_SYSCALL_TRACE |           \
-                                SYSCALL_WORK_SYSCALL_EMU)
+                                SYSCALL_WORK_SYSCALL_EMU |             \
+                                SYSCALL_WORK_SYSCALL_AUDIT)
 #define SYSCALL_WORK_EXIT      (SYSCALL_WORK_SYSCALL_TRACEPOINT |      \
-                                SYSCALL_WORK_SYSCALL_TRACE)
+                                SYSCALL_WORK_SYSCALL_TRACE |           \
+                                SYSCALL_WORK_SYSCALL_AUDIT)
 
 /*
  * TIF flags handled in exit_to_user_mode_loop()

diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 85b8a42161682d4904fae20edaef05f7b9080563..317363212ae96f819544c94c011c0ebe600e5c7e 100644 (file)
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -40,12 +40,14 @@ enum syscall_work_bit {
        SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT,
        SYSCALL_WORK_BIT_SYSCALL_TRACE,
        SYSCALL_WORK_BIT_SYSCALL_EMU,
+       SYSCALL_WORK_BIT_SYSCALL_AUDIT,
 };
 
 #define SYSCALL_WORK_SECCOMP           BIT(SYSCALL_WORK_BIT_SECCOMP)
 #define SYSCALL_WORK_SYSCALL_TRACEPOINT        BIT(SYSCALL_WORK_BIT_SYSCALL_TRACEPOINT)
 #define SYSCALL_WORK_SYSCALL_TRACE     BIT(SYSCALL_WORK_BIT_SYSCALL_TRACE)
 #define SYSCALL_WORK_SYSCALL_EMU       BIT(SYSCALL_WORK_BIT_SYSCALL_EMU)
+#define SYSCALL_WORK_SYSCALL_AUDIT     BIT(SYSCALL_WORK_BIT_SYSCALL_AUDIT)
 
 #include <asm/thread_info.h>
 

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 8dba8f0983b5c0485c54d9a12ba2b206cdc9ffe4..c00aa58379657589d39812ac7a9041571e192e4b 100644 (file)
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -952,7 +952,7 @@ int audit_alloc(struct task_struct *tsk)
 
        state = audit_filter_task(tsk, &key);
        if (state == AUDIT_DISABLED) {
-               clear_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
+               clear_task_syscall_work(tsk, SYSCALL_AUDIT);
                return 0;
        }
 
@@ -964,7 +964,7 @@ int audit_alloc(struct task_struct *tsk)
        context->filterkey = key;
 
        audit_set_context(tsk, context);
-       set_tsk_thread_flag(tsk, TIF_SYSCALL_AUDIT);
+       set_task_syscall_work(tsk, SYSCALL_AUDIT);
        return 0;
 }