[tip: core/entry] audit: Migrate to use SYSCALL_WORK flag

tip-bot2 for Gabriel Krisman Bertazi
2020-11-16T21:12:00Z

The following commit has been merged into the core/entry branch of tip:

Commit-ID: 785dc4eb7fd74e3b7f4eac468457b633117e1aea
Gitweb: https://git.kernel.org/tip/785dc4eb7fd74e3b7f4eac468457b633117e1aea
Author: Gabriel Krisman Bertazi <krisman@collabora.com>
AuthorDate: Mon, 16 Nov 2020 12:42:04 -05:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 16 Nov 2020 21:53:16 +01:00

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
---
include/asm-generic/syscall.h | 23 ++++++++++++++---------
include/linux/entry-common.h | 18 ++++++------------
include/linux/thread_info.h | 2 ++
kernel/auditsc.c | 4 ++--
4 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index ed94e56..524218a 100644
--- 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 b30f82b..d7b96f4 100644
--- 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 85b8a42..3173632 100644
--- 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 8dba8f0..c00aa58 100644
--- 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;
}