xfs: check for obviously bad level values in the bmbt root

[mirror_ubuntu-zesty-kernel.git] / fs / read_write.c

diff --git a/fs/read_write.c b/fs/read_write.c
index da6de12b5c46d4a56e15e892f527153682ff6e30..f9f8bb137806b20a44019073f3ecd0380449a9f3 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -20,7 +20,7 @@
 #include <linux/fs.h>
 #include "internal.h"
 
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 #include <asm/unistd.h>
 
 typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
@@ -515,6 +515,30 @@ ssize_t __vfs_write(struct file *file, const char __user *p, size_t count,
 }
 EXPORT_SYMBOL(__vfs_write);
 
+vfs_readf_t vfs_readf(struct file *file)
+{
+       const struct file_operations *fop = file->f_op;
+
+       if (fop->read)
+               return fop->read;
+       if (fop->read_iter)
+               return new_sync_read;
+       return ERR_PTR(-ENOSYS);
+}
+EXPORT_SYMBOL_GPL(vfs_readf);
+
+vfs_writef_t vfs_writef(struct file *file)
+{
+       const struct file_operations *fop = file->f_op;
+
+       if (fop->write)
+               return fop->write;
+       if (fop->write_iter)
+               return new_sync_write;
+       return ERR_PTR(-ENOSYS);
+}
+EXPORT_SYMBOL_GPL(vfs_writef);
+
 ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
 {
        mm_segment_t old_fs;
@@ -1669,6 +1693,9 @@ static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write)
  * Check that the two inodes are eligible for cloning, the ranges make
  * sense, and then flush all dirty data.  Caller must ensure that the
  * inodes have been locked against any other modifications.
+ *
+ * Returns: 0 for "nothing to clone", 1 for "something to clone", or
+ * the usual negative error code.
  */
 int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
                               struct inode *inode_out, loff_t pos_out,
@@ -1695,17 +1722,15 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
 
        /* Are we going all the way to the end? */
        isize = i_size_read(inode_in);
-       if (isize == 0) {
-               *len = 0;
+       if (isize == 0)
                return 0;
-       }
 
        /* Zero length dedupe exits immediately; reflink goes to EOF. */
        if (*len == 0) {
-               if (is_dedupe) {
-                       *len = 0;
+               if (is_dedupe || pos_in == isize)
                        return 0;
-               }
+               if (pos_in > isize)
+                       return -EINVAL;
                *len = isize - pos_in;
        }
 
@@ -1769,7 +1794,7 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,
                        return -EBADE;
        }
 
-       return 0;
+       return 1;
 }
 EXPORT_SYMBOL(vfs_clone_file_prep_inodes);
 
@@ -1955,6 +1980,9 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
                goto out;
        ret = 0;
 
+       if (off + len > i_size_read(src))
+               return -EINVAL;
+
        /* pre-format output fields to sane values */
        for (i = 0; i < count; i++) {
                same->info[i].bytes_deduped = 0ULL;