kexec: replace call to copy_file_from_fd() with kernel version

Replace copy_file_from_fd() with kernel_read_file_from_fd().

Two new identifiers named READING_KEXEC_IMAGE and READING_KEXEC_INITRAMFS
are defined for measuring, appraising or auditing the kexec image and
initramfs.

Changelog v3:
- return -EBADF, not -ENOEXEC
- identifier change
- split patch, moving copy_file_from_fd() to a separate patch
- split patch, moving IMA changes to a separate patch
v0:
- use kstat file size type loff_t, not size_t
- Calculate the file hash from the in memory buffer - Dave Young

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Acked-by: Dave Young <dyoung@redhat.com>

diff --git a/include/linux/fs.h b/include/linux/fs.h
index fb08b66..5256725 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2579,6 +2579,8 @@ extern int do_pipe_flags(int *, int);
 enum kernel_read_file_id {
        READING_FIRMWARE = 1,
        READING_MODULE,
+       READING_KEXEC_IMAGE,
+       READING_KEXEC_INITRAMFS,
        READING_MAX_ID
 };
 

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 007b791..b696c3f 100644 (file)
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -18,6 +18,7 @@
 #include <linux/kexec.h>
 #include <linux/mutex.h>
 #include <linux/list.h>
+#include <linux/fs.h>
 #include <crypto/hash.h>
 #include <crypto/sha.h>
 #include <linux/syscalls.h>
@@ -33,65 +34,6 @@ size_t __weak kexec_purgatory_size = 0;
 
 static int kexec_calculate_store_digests(struct kimage *image);
 
-static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
-{
-       struct fd f = fdget(fd);
-       int ret;
-       struct kstat stat;
-       loff_t pos;
-       ssize_t bytes = 0;
-
-       if (!f.file)
-               return -EBADF;
-
-       ret = vfs_getattr(&f.file->f_path, &stat);
-       if (ret)
-               goto out;
-
-       if (stat.size > INT_MAX) {
-               ret = -EFBIG;
-               goto out;
-       }
-
-       /* Don't hand 0 to vmalloc, it whines. */
-       if (stat.size == 0) {
-               ret = -EINVAL;
-               goto out;
-       }
-
-       *buf = vmalloc(stat.size);
-       if (!*buf) {
-               ret = -ENOMEM;
-               goto out;
-       }
-
-       pos = 0;
-       while (pos < stat.size) {
-               bytes = kernel_read(f.file, pos, (char *)(*buf) + pos,
-                                   stat.size - pos);
-               if (bytes < 0) {
-                       vfree(*buf);
-                       ret = bytes;
-                       goto out;
-               }
-
-               if (bytes == 0)
-                       break;
-               pos += bytes;
-       }
-
-       if (pos != stat.size) {
-               ret = -EBADF;
-               vfree(*buf);
-               goto out;
-       }
-
-       *buf_len = pos;
-out:
-       fdput(f);
-       return ret;
-}
-
 /* Architectures can provide this probe function */
 int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
                                         unsigned long buf_len)
@@ -182,16 +124,17 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 {
        int ret = 0;
        void *ldata;
+       loff_t size;
 
-       ret = copy_file_from_fd(kernel_fd, &image->kernel_buf,
-                               &image->kernel_buf_len);
+       ret = kernel_read_file_from_fd(kernel_fd, &image->kernel_buf,
+                                      &size, INT_MAX, READING_KEXEC_IMAGE);
        if (ret)
                return ret;
+       image->kernel_buf_len = size;
 
        /* Call arch image probe handlers */
        ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
                                            image->kernel_buf_len);
-
        if (ret)
                goto out;
 
@@ -206,10 +149,12 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 #endif
        /* It is possible that there no initramfs is being loaded */
        if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
-               ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
-                                       &image->initrd_buf_len);
+               ret = kernel_read_file_from_fd(initrd_fd, &image->initrd_buf,
+                                              &size, INT_MAX,
+                                              READING_KEXEC_INITRAMFS);
                if (ret)
                        goto out;
+               image->initrd_buf_len = size;
        }
 
        if (cmdline_len) {