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authorJan Kara <jack@suse.cz>2019-11-21 16:14:38 -0800
committerDarrick J. Wong <darrick.wong@oracle.com>2019-11-22 08:36:02 -0800
commit419e9c38aa075ed0cd3c13d47e15954b686bcdb6 (patch)
tree2856c172882cafbb709ed9c358dc621a55b8a767
parent6334b91e502ca1ec10157f2a3a2c74eea6b5e279 (diff)
downloadlinux-419e9c38aa075ed0cd3c13d47e15954b686bcdb6.tar.bz2
iomap: Fix pipe page leakage during splicing
When splicing using iomap_dio_rw() to a pipe, we may leak pipe pages because bio_iov_iter_get_pages() records that the pipe will have full extent worth of data however if file size is not block size aligned iomap_dio_rw() returns less than what bio_iov_iter_get_pages() set up and splice code gets confused leaking a pipe page with the file tail. Handle the situation similarly to the old direct IO implementation and revert iter to actually returned read amount which makes iter consistent with value returned from iomap_dio_rw() and thus the splice code is happy. Fixes: ff6a9292e6f6 ("iomap: implement direct I/O") CC: stable@vger.kernel.org Reported-by: syzbot+991400e8eba7e00a26e1@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
-rw-r--r--fs/iomap/direct-io.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index b77ec2acb066..420c0c82f0ac 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -502,8 +502,15 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
}
pos += ret;
- if (iov_iter_rw(iter) == READ && pos >= dio->i_size)
+ if (iov_iter_rw(iter) == READ && pos >= dio->i_size) {
+ /*
+ * We only report that we've read data up to i_size.
+ * Revert iter to a state corresponding to that as
+ * some callers (such as splice code) rely on it.
+ */
+ iov_iter_revert(iter, pos - dio->i_size);
break;
+ }
} while ((count = iov_iter_count(iter)) > 0);
blk_finish_plug(&plug);