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5287b07f6d
These routines are used in places outside of exec(2), so in preparation for refactoring them, move them into a separate source file, fs/kernel_read_file.c. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Scott Branden <scott.branden@broadcom.com> Link: https://lore.kernel.org/r/20201002173828.2099543-5-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
139 lines
2.6 KiB
C
139 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/fs.h>
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#include <linux/fs_struct.h>
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#include <linux/kernel_read_file.h>
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#include <linux/security.h>
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#include <linux/vmalloc.h>
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int kernel_read_file(struct file *file, void **buf, loff_t *size,
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loff_t max_size, enum kernel_read_file_id id)
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{
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loff_t i_size, pos;
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ssize_t bytes = 0;
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void *allocated = NULL;
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int ret;
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if (!S_ISREG(file_inode(file)->i_mode) || max_size < 0)
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return -EINVAL;
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ret = deny_write_access(file);
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if (ret)
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return ret;
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ret = security_kernel_read_file(file, id);
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if (ret)
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goto out;
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i_size = i_size_read(file_inode(file));
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if (i_size <= 0) {
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ret = -EINVAL;
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goto out;
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}
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if (i_size > SIZE_MAX || (max_size > 0 && i_size > max_size)) {
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ret = -EFBIG;
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goto out;
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}
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if (!*buf)
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*buf = allocated = vmalloc(i_size);
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if (!*buf) {
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ret = -ENOMEM;
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goto out;
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}
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pos = 0;
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while (pos < i_size) {
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bytes = kernel_read(file, *buf + pos, i_size - pos, &pos);
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if (bytes < 0) {
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ret = bytes;
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goto out_free;
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}
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if (bytes == 0)
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break;
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}
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if (pos != i_size) {
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ret = -EIO;
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goto out_free;
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}
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ret = security_kernel_post_read_file(file, *buf, i_size, id);
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if (!ret)
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*size = pos;
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out_free:
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if (ret < 0) {
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if (allocated) {
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vfree(*buf);
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*buf = NULL;
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}
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}
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out:
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allow_write_access(file);
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return ret;
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}
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EXPORT_SYMBOL_GPL(kernel_read_file);
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int kernel_read_file_from_path(const char *path, void **buf, loff_t *size,
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loff_t max_size, enum kernel_read_file_id id)
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{
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struct file *file;
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int ret;
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if (!path || !*path)
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return -EINVAL;
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file = filp_open(path, O_RDONLY, 0);
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if (IS_ERR(file))
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return PTR_ERR(file);
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ret = kernel_read_file(file, buf, size, max_size, id);
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fput(file);
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return ret;
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}
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EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
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int kernel_read_file_from_path_initns(const char *path, void **buf,
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loff_t *size, loff_t max_size,
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enum kernel_read_file_id id)
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{
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struct file *file;
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struct path root;
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int ret;
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if (!path || !*path)
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return -EINVAL;
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task_lock(&init_task);
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get_fs_root(init_task.fs, &root);
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task_unlock(&init_task);
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file = file_open_root(root.dentry, root.mnt, path, O_RDONLY, 0);
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path_put(&root);
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if (IS_ERR(file))
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return PTR_ERR(file);
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ret = kernel_read_file(file, buf, size, max_size, id);
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fput(file);
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return ret;
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}
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EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
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int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
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enum kernel_read_file_id id)
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{
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struct fd f = fdget(fd);
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int ret = -EBADF;
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if (!f.file)
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goto out;
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ret = kernel_read_file(f.file, buf, size, max_size, id);
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out:
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fdput(f);
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return ret;
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}
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EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
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