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>

diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
index 0dc5a3d..1145c58 100644 (file)
--- 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;
 }