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[for-next,2/4] io_uring: support 0 length iov in buffer select in compat

Message ID 20220708181838.1495428-3-dylany@fb.com (mailing list archive)
State New
Headers show
Series io_uring: multishot recv cleanups | expand

Commit Message

Dylan Yudaken July 8, 2022, 6:18 p.m. UTC
Match up work done in "io_uring: allow iov_len = 0 for recvmsg and buffer
select", but for compat code path.

Fixes: a68caad69ce5 ("io_uring: allow iov_len = 0 for recvmsg and buffer select")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
---
 io_uring/net.c | 23 ++++++++++++++---------
 1 file changed, 14 insertions(+), 9 deletions(-)
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Patch

diff --git a/io_uring/net.c b/io_uring/net.c
index 188edbed1eb7..997c17512694 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -384,16 +384,21 @@  static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
 	if (req->flags & REQ_F_BUFFER_SELECT) {
 		compat_ssize_t clen;
 
-		if (len > 1)
-			return -EINVAL;
-		if (!access_ok(uiov, sizeof(*uiov)))
-			return -EFAULT;
-		if (__get_user(clen, &uiov->iov_len))
-			return -EFAULT;
-		if (clen < 0)
+		if (len == 0) {
+			sr->len = 0;
+			iomsg->free_iov = NULL;
+		} else if (len > 1) {
 			return -EINVAL;
-		sr->len = clen;
-		iomsg->free_iov = NULL;
+		} else {
+			if (!access_ok(uiov, sizeof(*uiov)))
+				return -EFAULT;
+			if (__get_user(clen, &uiov->iov_len))
+				return -EFAULT;
+			if (clen < 0)
+				return -EINVAL;
+			sr->len = clen;
+			iomsg->free_iov = NULL;
+		}
 	} else {
 		iomsg->free_iov = iomsg->fast_iov;
 		ret = __import_iovec(READ, (struct iovec __user *)uiov, len,