eCryptfs: Report errors in writes to /dev/ecryptfs

Errors in writes to /dev/ecryptfs were being incorrectly reported by
returning 0 or the value of the original write count.

This patch clears up the return code assignment in error paths.

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

1 files changed, 13 insertions, 11 deletions

diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
index 0dc5a3d554a..1145c58103e 100644
--- a/fs/ecryptfs/miscdev.c
+++ b/fs/ecryptfs/miscdev.c
@@ -406,14 +406,13 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf,
         __be32 counter_nbo;
         u32 seq;
         size_t packet_size, packet_size_length, i;
-        ssize_t sz = 0;
         char *data;
         uid_t euid = current_euid();
         unsigned char packet_size_peek[3];
-        int rc;
+        ssize_t rc;
 
         if (count == 0) {
-                goto out;
+                return 0;
         } else if (count == (1 + 4)) {
                 /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
                 goto memdup;
@@ -439,7 +438,7 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf,
                                           &packet_size_length);
         if (rc) {
                 printk(KERN_WARNING "%s: Error parsing packet length; "
-                       "rc = [%d]\n", __func__, rc);
+                       "rc = [%zd]\n", __func__, rc);
                 return rc;
         }
 
@@ -454,9 +453,8 @@ memdup:
         if (IS_ERR(data)) {
                 printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
                        __func__, PTR_ERR(data));
-                goto out;
+                return PTR_ERR(data);
         }
-        sz = count;
         i = 0;
         switch (data[i++]) {
         case ECRYPTFS_MSG_RESPONSE:
@@ -467,6 +465,7 @@ memdup:
                                __func__,
                                (1 + 4 + 1 + sizeof(struct ecryptfs_message)),
                                count);
+                        rc = -EINVAL;
                         goto out_free;
                 }
                 memcpy(&counter_nbo, &data[i], 4);
@@ -475,10 +474,12 @@ memdup:
                 rc = ecryptfs_miscdev_response(&data[i], packet_size,
                                                euid, current_user_ns(),
                                                task_pid(current), seq);
-                if (rc)
+                if (rc) {
                         printk(KERN_WARNING "%s: Failed to deliver miscdev "
-                               "response to requesting operation; rc = [%d]\n",
+                               "response to requesting operation; rc = [%zd]\n",
                                __func__, rc);
+                        goto out_free;
+                }
                 break;
         case ECRYPTFS_MSG_HELO:
         case ECRYPTFS_MSG_QUIT:
@@ -487,12 +488,13 @@ memdup:
                 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
                                 "message of unrecognized type [%d]\n",
                                 data[0]);
-                break;
+                rc = -EINVAL;
+                goto out_free;
         }
+        rc = count;
 out_free:
         kfree(data);
-out:
-        return sz;
+        return rc;
 }