From d876836204897b6d7d911f942084f69a1e9d5c4d Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 27 Feb 2020 14:17:49 -0700
Subject: [PATCH] io_uring: fix 32-bit compatability with sendmsg/recvmsg
We must set MSG_CMSG_COMPAT if we're in compatability mode, otherwise
the iovec import for these commands will not do the right thing and fail
the command with -EINVAL.
Found by running the test suite compiled as 32-bit.
Cc: stable@vger.kernel.org
Fixes: aa1fa28fc73e ("io_uring: add support for recvmsg()")
Fixes: 0fa03c624d8f ("io_uring: add support for sendmsg()")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 05eea06f5421b..6a595c13e108c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3001,6 +3001,11 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
+#ifdef CONFIG_COMPAT
+ if (req->ctx->compat)
+ sr->msg_flags |= MSG_CMSG_COMPAT;
+#endif
+
if (!io || req->opcode == IORING_OP_SEND)
return 0;
/* iovec is already imported */
@@ -3153,6 +3158,11 @@ static int io_recvmsg_prep(struct io_kiocb *req,
sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
+#ifdef CONFIG_COMPAT
+ if (req->ctx->compat)
+ sr->msg_flags |= MSG_CMSG_COMPAT;
+#endif
+
if (!io || req->opcode == IORING_OP_RECV)
return 0;
/* iovec is already imported */
--
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