Add initial support for the ambient set.

The ambient set is some strangeness associated with trying to revive
naive inheritance. While personally not a fan of this feature, I
recognize it is in the kernel so libcap now supports it with
three new functions:

  int cap_get_ambient(cap_value_t cap)
  int cap_set_ambient(cap_value_t cap, cap_flag_value_t set)
  int cap_reset_ambient(void)

Signed-off-by: Andrew G. Morgan <morgan@kernel.org>

2 files changed, 53 insertions, 1 deletions

diff --git a/libcap/include/sys/capability.h b/libcap/include/sys/capability.h
index dddc75b..0976fa7 100644
--- a/libcap/include/sys/capability.h
+++ b/libcap/include/sys/capability.h
@@ -92,9 +92,13 @@ extern int     cap_set_proc(cap_t);
 
 extern int     cap_get_bound(cap_value_t);
 extern int     cap_drop_bound(cap_value_t);
-
 #define CAP_IS_SUPPORTED(cap)  (cap_get_bound(cap) >= 0)
 
+extern int     cap_get_ambient(cap_value_t);
+extern int     cap_set_ambient(cap_value_t, cap_flag_value_t);
+extern int     cap_reset_ambient(void);
+#define CAP_AMBIENT_SUPPORTED() (cap_get_ambient(CAP_CHOWN) >= 0)
+
 /* libcap/cap_extint.c */
 extern ssize_t cap_size(cap_t);
 extern ssize_t cap_copy_ext(void *, cap_t, ssize_t);
diff --git a/libcap/include/uapi/linux/prctl.h b/libcap/include/uapi/linux/prctl.h
index 289760f..a8d0759 100644
--- a/libcap/include/uapi/linux/prctl.h
+++ b/libcap/include/uapi/linux/prctl.h
@@ -1,6 +1,8 @@
 #ifndef _LINUX_PRCTL_H
 #define _LINUX_PRCTL_H
 
+#include <linux/types.h>
+
 /* Values to pass as first argument to prctl() */
 
 #define PR_SET_PDEATHSIG  1  /* Second arg is a signal */
@@ -119,6 +121,31 @@
 # define PR_SET_MM_ENV_END		11
 # define PR_SET_MM_AUXV			12
 # define PR_SET_MM_EXE_FILE		13
+# define PR_SET_MM_MAP			14
+# define PR_SET_MM_MAP_SIZE		15
+
+/*
+ * This structure provides new memory descriptor
+ * map which mostly modifies /proc/pid/stat[m]
+ * output for a task. This mostly done in a
+ * sake of checkpoint/restore functionality.
+ */
+struct prctl_mm_map {
+	__u64	start_code;		/* code section bounds */
+	__u64	end_code;
+	__u64	start_data;		/* data section bounds */
+	__u64	end_data;
+	__u64	start_brk;		/* heap for brk() syscall */
+	__u64	brk;
+	__u64	start_stack;		/* stack starts at */
+	__u64	arg_start;		/* command line arguments bounds */
+	__u64	arg_end;
+	__u64	env_start;		/* environment variables bounds */
+	__u64	env_end;
+	__u64	*auxv;			/* auxiliary vector */
+	__u32	auxv_size;		/* vector size */
+	__u32	exe_fd;			/* /proc/$pid/exe link file */
+};
 
 /*
  * Set specific pid that is allowed to ptrace the current task.
@@ -149,4 +176,25 @@
 
 #define PR_GET_TID_ADDRESS	40
 
+#define PR_SET_THP_DISABLE	41
+#define PR_GET_THP_DISABLE	42
+
+/*
+ * Tell the kernel to start/stop helping userspace manage bounds tables.
+ */
+#define PR_MPX_ENABLE_MANAGEMENT  43
+#define PR_MPX_DISABLE_MANAGEMENT 44
+
+#define PR_SET_FP_MODE		45
+#define PR_GET_FP_MODE		46
+# define PR_FP_MODE_FR		(1 << 0)	/* 64b FP registers */
+# define PR_FP_MODE_FRE		(1 << 1)	/* 32b compatibility */
+
+/* Control the ambient capability set */
+#define PR_CAP_AMBIENT			47
+# define PR_CAP_AMBIENT_IS_SET		1
+# define PR_CAP_AMBIENT_RAISE		2
+# define PR_CAP_AMBIENT_LOWER		3
+# define PR_CAP_AMBIENT_CLEAR_ALL	4
+
 #endif /* _LINUX_PRCTL_H */