Depending on CONFIG_HAVE_ARCH_SECCOMP_FILTER, __secure_computing(NULL)
will crash or not. This is not consistent/safe, especially considering
that after the previous change __secure_computing(sd) is always called
with sd == NULL.
Fortunately, if CONFIG_HAVE_ARCH_SECCOMP_FILTER=n, __secure_computing()
has no callers, these architectures use secure_computing_strict(). Yet
it make sense make __secure_computing(NULL) safe in this case.
Note also that with this change we can unexport secure_computing_strict()
and change the current callers to use __secure_computing(NULL).
Fixes: 8cf8dfceebda ("seccomp: Stub for !HAVE_ARCH_SECCOMP_FILTER")
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
---
include/linux/seccomp.h | 8 ++------
kernel/seccomp.c | 14 ++++++++++----
2 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h
index e45531455d3b..d55949071c30 100644
--- a/include/linux/seccomp.h
+++ b/include/linux/seccomp.h
@@ -22,8 +22,9 @@
#include <linux/atomic.h>
#include <asm/seccomp.h>
-#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
extern int __secure_computing(const struct seccomp_data *sd);
+
+#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
static inline int secure_computing(void)
{
if (unlikely(test_syscall_work(SECCOMP)))
@@ -32,11 +33,6 @@ static inline int secure_computing(void)
}
#else
extern void secure_computing_strict(int this_syscall);
-static inline int __secure_computing(const struct seccomp_data *sd)
-{
- secure_computing_strict(sd->nr);
- return 0;
-}
#endif
extern long prctl_get_seccomp(void);
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 385d48293a5f..327b7b486f1c 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -29,13 +29,11 @@
#include <linux/syscalls.h>
#include <linux/sysctl.h>
+#include <asm/syscall.h>
+
/* Not exposed in headers: strictly internal use only. */
#define SECCOMP_MODE_DEAD (SECCOMP_MODE_FILTER + 1)
-#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
-#include <asm/syscall.h>
-#endif
-
#ifdef CONFIG_SECCOMP_FILTER
#include <linux/file.h>
#include <linux/filter.h>
@@ -1062,6 +1060,14 @@ void secure_computing_strict(int this_syscall)
else
BUG();
}
+int __secure_computing(const struct seccomp_data *sd)
+{
+ int this_syscall = sd ? sd->nr :
+ syscall_get_nr(current, current_pt_regs());
+
+ secure_computing_strict(this_syscall);
+ return 0;
+}
#else
#ifdef CONFIG_SECCOMP_FILTER
--
2.25.1.362.g51ebf55
