kexec: return -EFAULT on copy_to_user() failures

copy_to/from_user() returns the number of bytes remaining to be copied.
It never returns a negative value.  The correct return code is -EFAULT and
not -EIO.

All the callers check for non-zero returns so that's Ok, but the return
code is passed to the user so we should fix this.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Simon Kagstrom <simon.kagstrom@netinsight.net>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 131b1703936f6dbe71cf84c2ff572efef6c47e70..c0613f7d673064b7bbe1afcf7477dd569310989c 100644 (file)
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -151,8 +151,10 @@ static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
        image->nr_segments = nr_segments;
        segment_bytes = nr_segments * sizeof(*segments);
        result = copy_from_user(image->segment, segments, segment_bytes);
-       if (result)
+       if (result) {
+               result = -EFAULT;
                goto out;
+       }
 
        /*
         * Verify we have good destination addresses.  The caller is
@@ -827,7 +829,7 @@ static int kimage_load_normal_segment(struct kimage *image,
                result = copy_from_user(ptr, buf, uchunk);
                kunmap(page);
                if (result) {
-                       result = (result < 0) ? result : -EIO;
+                       result = -EFAULT;
                        goto out;
                }
                ubytes -= uchunk;
@@ -882,7 +884,7 @@ static int kimage_load_crash_segment(struct kimage *image,
                kexec_flush_icache_page(page);
                kunmap(page);
                if (result) {
-                       result = (result < 0) ? result : -EIO;
+                       result = -EFAULT;
                        goto out;
                }
                ubytes -= uchunk;