io_uring: Fix premature return from loop and memory leak

Currently the -EINVAL error return path is leaking memory allocated
to data. Fix this by not returning immediately but instead setting
the error return variable to -EINVAL and breaking out of the loop.

Kudos to Pavel Begunkov for suggesting a correct fix.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20210429104602.62676-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 82117e6..a880edb 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8417,8 +8417,10 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
                ret = io_buffer_validate(&iov);
                if (ret)
                        break;
-               if (!iov.iov_base && tag)
-                       return -EINVAL;
+               if (!iov.iov_base && tag) {
+                       ret = -EINVAL;
+                       break;
+               }
 
                ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
                                             &last_hpage);
@@ -8468,8 +8470,10 @@ static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
                err = io_buffer_validate(&iov);
                if (err)
                        break;
-               if (!iov.iov_base && tag)
-                       return -EINVAL;
+               if (!iov.iov_base && tag) {
+                       err = -EINVAL;
+                       break;
+               }
                err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
                if (err)
                        break;