From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
The kernel doesn't have direct visibility to the ELF contents of shared
libraries. Add some prctl() interfaces which allow glibc to tell the
kernel where to find .sframe sections.
[
This adds an interface for prctl() for testing loading of sframes for
libraries. But this interface should really be a system call. This patch
is for testing purposes only and should not be applied to mainline.
]
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
include/uapi/linux/prctl.h | 6 +++++-
kernel/sys.c | 9 +++++++++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 43dec6eed559..c575cf7151b1 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -351,7 +351,7 @@ struct prctl_mm_map {
* configuration. All bits may be locked via this call, including
* undefined bits.
*/
-#define PR_LOCK_SHADOW_STACK_STATUS 76
+#define PR_LOCK_SHADOW_STACK_STATUS 76
/*
* Controls the mode of timer_create() for CRIU restore operations.
@@ -371,4 +371,8 @@ struct prctl_mm_map {
# define PR_FUTEX_HASH_GET_SLOTS 2
# define PR_FUTEX_HASH_GET_IMMUTABLE 3
+/* SFRAME management */
+#define PR_ADD_SFRAME 79
+#define PR_REMOVE_SFRAME 80
+
#endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index adc0de0aa364..cf788e66dc86 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -65,6 +65,7 @@
#include <linux/rcupdate.h>
#include <linux/uidgid.h>
#include <linux/cred.h>
+#include <linux/sframe.h>
#include <linux/nospec.h>
@@ -2824,6 +2825,14 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
case PR_FUTEX_HASH:
error = futex_hash_prctl(arg2, arg3, arg4);
break;
+ case PR_ADD_SFRAME:
+ error = sframe_add_section(arg2, arg3, arg4, arg5);
+ break;
+ case PR_REMOVE_SFRAME:
+ if (arg3 || arg4 || arg5)
+ return -EINVAL;
+ error = sframe_remove_section(arg2);
+ break;
default:
trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5);
error = -EINVAL;
--
2.47.2
