kexec: return error if file bytes are less then file size

If number of bytes read from file are not same as file size, return error.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 32fd3d48bc8c..99558a3cb08d 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -331,7 +331,7 @@ out_free_image:
 static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
 {
 	struct fd f = fdget(fd);
-	int ret = 0;
+	int ret;
 	struct kstat stat;
 	loff_t pos;
 	ssize_t bytes = 0;
@@ -375,6 +375,12 @@ static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
 		pos += bytes;
 	}
 
+	if (pos != stat.size) {
+		ret = -EBADF;
+		vfree(*buf);
+		goto out;
+	}
+
 	*buf_len = pos;
 out:
 	fdput(f);