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-rw-r--r--fs/cifs/file.c37
1 files changed, 34 insertions, 3 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 290b4966004f..18758bcd4dab 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2389,7 +2389,7 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
unsigned long nr_segs, loff_t *poffset)
{
unsigned long nr_pages, i;
- size_t copied, len, cur_len;
+ size_t bytes, copied, len, cur_len;
ssize_t total_written = 0;
loff_t offset;
struct iov_iter it;
@@ -2444,14 +2444,45 @@ cifs_iovec_write(struct file *file, const struct iovec *iov,
save_len = cur_len;
for (i = 0; i < nr_pages; i++) {
- copied = min_t(const size_t, cur_len, PAGE_SIZE);
+ bytes = min_t(const size_t, cur_len, PAGE_SIZE);
copied = iov_iter_copy_from_user(wdata->pages[i], &it,
- 0, copied);
+ 0, bytes);
cur_len -= copied;
iov_iter_advance(&it, copied);
+ /*
+ * If we didn't copy as much as we expected, then that
+ * may mean we trod into an unmapped area. Stop copying
+ * at that point. On the next pass through the big
+ * loop, we'll likely end up getting a zero-length
+ * write and bailing out of it.
+ */
+ if (copied < bytes)
+ break;
}
cur_len = save_len - cur_len;
+ /*
+ * If we have no data to send, then that probably means that
+ * the copy above failed altogether. That's most likely because
+ * the address in the iovec was bogus. Set the rc to -EFAULT,
+ * free anything we allocated and bail out.
+ */
+ if (!cur_len) {
+ for (i = 0; i < nr_pages; i++)
+ put_page(wdata->pages[i]);
+ kfree(wdata);
+ rc = -EFAULT;
+ break;
+ }
+
+ /*
+ * i + 1 now represents the number of pages we actually used in
+ * the copy phase above. Bring nr_pages down to that, and free
+ * any pages that we didn't use.
+ */
+ for ( ; nr_pages > i + 1; nr_pages--)
+ put_page(wdata->pages[nr_pages - 1]);
+
wdata->sync_mode = WB_SYNC_ALL;
wdata->nr_pages = nr_pages;
wdata->offset = (__u64)offset;