Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[sfrench/cifs-2.6.git] / fs / read_write.c

diff --git a/fs/read_write.c b/fs/read_write.c
index 603794b207ebad39946e96bcbfff73332fc9a0a0..5a2ee488c5d2a3b35cb8cb941c652215cb96f7da 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1407,7 +1407,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
                goto fput_in;
        if (!(out.file->f_mode & FMODE_WRITE))
                goto fput_out;
-       retval = -EINVAL;
        in_inode = file_inode(in.file);
        out_inode = file_inode(out.file);
        out_pos = out.file->f_pos;
@@ -1977,6 +1976,20 @@ out_error:
 }
 EXPORT_SYMBOL(vfs_dedupe_file_range_compare);
 
+/* Check whether we are allowed to dedupe the destination file */
+static bool allow_file_dedupe(struct file *file)
+{
+       if (capable(CAP_SYS_ADMIN))
+               return true;
+       if (file->f_mode & FMODE_WRITE)
+               return true;
+       if (uid_eq(current_fsuid(), file_inode(file)->i_uid))
+               return true;
+       if (!inode_permission(file_inode(file), MAY_WRITE))
+               return true;
+       return false;
+}
+
 int vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
                              struct file *dst_file, loff_t dst_pos, u64 len)
 {
@@ -1990,8 +2003,8 @@ int vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
        if (ret < 0)
                goto out_drop_write;
 
-       ret = -EINVAL;
-       if (!(capable(CAP_SYS_ADMIN) || (dst_file->f_mode & FMODE_WRITE)))
+       ret = -EPERM;
+       if (!allow_file_dedupe(dst_file))
                goto out_drop_write;
 
        ret = -EXDEV;