[PATCH v6 02/11] exec: add dirfd parameter to kernel_execve()

["Thomas Weißschuh" <thomas.weissschuh@linutronix.de>]

Allow callers to specify the directory against which to resolve the
program filename. Enables running executables from private mounts.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
 fs/exec.c               | 4 ++--
 include/linux/binfmts.h | 2 +-
 init/main.c             | 2 +-
 kernel/umh.c            | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index ba12b4c466f6..affae4b4f6f6 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1846,7 +1846,7 @@ static int do_execveat_common(int fd, struct filename *filename,
 	return bprm_execve(bprm);
 }
 
-int kernel_execve(const char *kernel_filename,
+int kernel_execve(int dirfd, const char *kernel_filename,
 		  const char *const *argv, const char *const *envp)
 {
 	int retval;
@@ -1856,7 +1856,7 @@ int kernel_execve(const char *kernel_filename,
 		return -EINVAL;
 
 	CLASS(filename_kernel, filename)(kernel_filename);
-	CLASS(bprm, bprm)(AT_FDCWD, filename, 0);
+	CLASS(bprm, bprm)(dirfd, filename, 0);
 	if (IS_ERR(bprm))
 		return PTR_ERR(bprm);
 
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index 65abd5ab8836..04e2b7a85b2b 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -144,7 +144,7 @@ int copy_string_kernel(const char *arg, struct linux_binprm *bprm);
 extern void set_binfmt(struct linux_binfmt *new);
 extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);
 
-int kernel_execve(const char *filename,
+int kernel_execve(int dirfd, const char *filename,
 		  const char *const *argv, const char *const *envp);
 
 #endif /* _LINUX_BINFMTS_H */
diff --git a/init/main.c b/init/main.c
index 96f93bb06c49..551d03681234 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1511,7 +1511,7 @@ static int run_init_process(const char *init_filename)
 	pr_debug("  with environment:\n");
 	for (p = envp_init; *p; p++)
 		pr_debug("    %s\n", *p);
-	return kernel_execve(init_filename, argv_init, envp_init);
+	return kernel_execve(AT_FDCWD, init_filename, argv_init, envp_init);
 }
 
 static int try_to_run_init_process(const char *init_filename)
diff --git a/kernel/umh.c b/kernel/umh.c
index cffda97d961c..bab134fa8c36 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -106,7 +106,7 @@ static int call_usermodehelper_exec_async(void *data)
 	commit_creds(new);
 
 	wait_for_initramfs();
-	retval = kernel_execve(sub_info->path,
+	retval = kernel_execve(AT_FDCWD, sub_info->path,
 			       (const char *const *)sub_info->argv,
 			       (const char *const *)sub_info->envp);
 out:

-- 
2.53.0