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Commit 5f402c67 authored by Park Ju Hyung's avatar Park Ju Hyung Committed by KakatkarAkshay
Browse files

exec: use bprm from the stack space 



struct linux_binprm isn't big and is safe to use from the stack space

Signed-off-by: default avatarPark Ju Hyung <qkrwngud825@gmail.com>
[@0ctobot: Adapted for 4.19]
Signed-off-by: default avatarAdam W. Willis <return.of.octobot@gmail.com>
Signed-off-by: default avatarLibXZR <xzr467706992@163.com>
parent fd641941

fs/exec.c

+27 −32
Original line number Diff line number Diff line
@@ -1428,7 +1428,6 @@ static void free_bprm(struct linux_binprm *bprm) 
	/* If a binfmt changed the interp, free it. */

	if (bprm->interp != bprm->filename)

		kfree(bprm->interp);

	kfree(bprm);

}



int bprm_change_interp(const char *interp, struct linux_binprm *bprm)
@@ -1716,7 +1715,7 @@ static int __do_execve_file(int fd, struct filename *filename, 
			    int flags, struct file *file)

{

	char *pathbuf = NULL;

	struct linux_binprm *bprm;

	struct linux_binprm bprm;

	struct files_struct *displaced;

	int retval;
@@ -1743,16 +1742,13 @@ static int __do_execve_file(int fd, struct filename *filename, 
	if (retval)

		goto out_ret;



	retval = -ENOMEM;

	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);

	if (!bprm)

		goto out_files;

	memset(&bprm, 0, sizeof(bprm));



	retval = prepare_bprm_creds(bprm);

	retval = prepare_bprm_creds(&bprm);

	if (retval)

		goto out_free;



	check_unsafe_exec(bprm);

	check_unsafe_exec(&bprm);

	current->in_execve = 1;



	if (!file)
@@ -1763,11 +1759,11 @@ static int __do_execve_file(int fd, struct filename *filename, 


	sched_exec();



	bprm->file = file;

	bprm.file = file;

	if (!filename) {

		bprm->filename = "none";

		bprm.filename = "none";

	} else if (fd == AT_FDCWD || filename->name[0] == '/') {

		bprm->filename = filename->name;

		bprm.filename = filename->name;

	} else {

		if (filename->name[0] == '\0')

			pathbuf = kasprintf(GFP_KERNEL, "/dev/fd/%d", fd);
@@ -1784,43 +1780,43 @@ static int __do_execve_file(int fd, struct filename *filename, 
		 * current->files (due to unshare_files above).

		 */

		if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt)))

			bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;

		bprm->filename = pathbuf;

			bprm.interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;

		bprm.filename = pathbuf;

	}

	bprm->interp = bprm->filename;

	bprm.interp = bprm.filename;



	retval = bprm_mm_init(bprm);

	retval = bprm_mm_init(&bprm);

	if (retval)

		goto out_unmark;



	bprm->argc = count(argv, MAX_ARG_STRINGS);

	if ((retval = bprm->argc) < 0)

	bprm.argc = count(argv, MAX_ARG_STRINGS);

	if ((retval = bprm.argc) < 0)

		goto out;



	bprm->envc = count(envp, MAX_ARG_STRINGS);

	if ((retval = bprm->envc) < 0)

	bprm.envc = count(envp, MAX_ARG_STRINGS);

	if ((retval = bprm.envc) < 0)

		goto out;



	retval = prepare_binprm(bprm);

	retval = prepare_binprm(&bprm);

	if (retval < 0)

		goto out;



	retval = copy_strings_kernel(1, &bprm->filename, bprm);

	retval = copy_strings_kernel(1, &bprm.filename, &bprm);

	if (retval < 0)

		goto out;



	bprm->exec = bprm->p;

	retval = copy_strings(bprm->envc, envp, bprm);

	bprm.exec = bprm.p;

	retval = copy_strings(bprm.envc, envp, &bprm);

	if (retval < 0)

		goto out;



	retval = copy_strings(bprm->argc, argv, bprm);

	retval = copy_strings(bprm.argc, argv, &bprm);

	if (retval < 0)

		goto out;



	would_dump(bprm, bprm->file);

	would_dump(&bprm, bprm.file);



	retval = exec_binprm(bprm);

	retval = exec_binprm(&bprm);

	if (retval < 0)

		goto out;
@@ -1831,7 +1827,7 @@ static int __do_execve_file(int fd, struct filename *filename, 
	rseq_execve(current);

	acct_update_integrals(current);

	task_numa_free(current, false);

	free_bprm(bprm);

	free_bprm(&bprm);

	kfree(pathbuf);

	if (filename)

		putname(filename);
@@ -1840,9 +1836,9 @@ static int __do_execve_file(int fd, struct filename *filename, 
	return retval;



out:

	if (bprm->mm) {

		acct_arg_size(bprm, 0);

		mmput(bprm->mm);

	if (bprm.mm) {

		acct_arg_size(&bprm, 0);

		mmput(bprm.mm);

	}



out_unmark:
@@ -1850,10 +1846,9 @@ static int __do_execve_file(int fd, struct filename *filename, 
	current->in_execve = 0;



out_free:

	free_bprm(bprm);

	free_bprm(&bprm);

	kfree(pathbuf);



out_files:

	if (displaced)

		reset_files_struct(displaced);

out_ret: