[PATCH v2 1/2] iov_iter: mark truncated iters
From: Pavel Begunkov <asml.silence@gmail.com>
Date: 2021-08-12 20:41:31
Also in:
linux-fsdevel, lkml
Subsystem:
the rest, userspace copyin/copyout (uiovec) · Maintainers:
Linus Torvalds, Alexander Viro
Track if an iterator has ever been truncated. This will be used to mitigate revert-truncate problems. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> --- include/linux/uio.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 82c3c3e819e0..61b8d312d13a 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h@@ -30,6 +30,7 @@ enum iter_type { struct iov_iter { u8 iter_type; bool data_source; + bool truncated; size_t iov_offset; size_t count; union {
@@ -254,8 +255,10 @@ static inline void iov_iter_truncate(struct iov_iter *i, u64 count) * conversion in assignement is by definition greater than all * values of size_t, including old i->count. */ - if (i->count > count) + if (i->count > count) { i->count = count; + i->truncated = true; + } } /*
--
2.32.0