2 files changed, 16 insertions, 8 deletions
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 0afcdeb8995b..3c63ce19e3bf 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -19,13 +19,11 @@
 #include <um_malloc.h>
 #include "internal.h"
 
-#define PGD_BOUND (4 * 1024 * 1024)
 #define STACKSIZE (8 * 1024 * 1024)
-#define THREAD_NAME_LEN (256)
 
 long elf_aux_hwcap;
 
-static void set_stklim(void)
+static void __init set_stklim(void)
 {
 	struct rlimit lim;
 
@@ -48,7 +46,7 @@ static void last_ditch_exit(int sig)
 	exit(1);
 }
 
-static void install_fatal_handler(int sig)
+static void __init install_fatal_handler(int sig)
 {
 	struct sigaction action;
 
@@ -73,7 +71,7 @@ static void install_fatal_handler(int sig)
 
 #define UML_LIB_PATH	":" OS_LIB_PATH "/uml"
 
-static void setup_env_path(void)
+static void __init setup_env_path(void)
 {
 	char *new_path = NULL;
 	char *old_path = NULL;
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index f683cfc9e51a..e2f8f156402f 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -181,6 +181,10 @@ extern char __syscall_stub_start[];
 
 static int stub_exe_fd;
 
+#ifndef CLOSE_RANGE_CLOEXEC
+#define CLOSE_RANGE_CLOEXEC	(1U << 2)
+#endif
+
 static int userspace_tramp(void *stack)
 {
 	char *const argv[] = { "uml-userspace", NULL };
@@ -202,8 +206,12 @@ static int userspace_tramp(void *stack)
 	init_data.stub_data_fd = phys_mapping(uml_to_phys(stack), &offset);
 	init_data.stub_data_offset = MMAP_OFFSET(offset);
 
-	/* Set CLOEXEC on all FDs and then unset on all memory related FDs */
-	close_range(0, ~0U, CLOSE_RANGE_CLOEXEC);
+	/*
+	 * Avoid leaking unneeded FDs to the stub by setting CLOEXEC on all FDs
+	 * and then unsetting it on all memory related FDs.
+	 * This is not strictly necessary from a safety perspective.
+	 */
+	syscall(__NR_close_range, 0, ~0U, CLOSE_RANGE_CLOEXEC);
 
 	fcntl(init_data.stub_data_fd, F_SETFD, 0);
 	for (iomem = iomem_regions; iomem; iomem = iomem->next)
@@ -224,7 +232,9 @@ static int userspace_tramp(void *stack)
 	if (ret != sizeof(init_data))
 		exit(4);
 
-	execveat(stub_exe_fd, "", argv, NULL, AT_EMPTY_PATH);
+	/* Raw execveat for compatibility with older libc versions */
+	syscall(__NR_execveat, stub_exe_fd, (unsigned long)"",
+		(unsigned long)argv, NULL, AT_EMPTY_PATH);
 
 	exit(5);
 }