linux-kernel - [PATCH 5.4 152/232] io_uring: honor original task RLIMIT

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Message-Id: <20200416131334.008677152@linuxfoundation.org>
Date:   Thu, 16 Apr 2020 15:24:06 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jens Axboe <axboe@...nel.dk>
Subject: [PATCH 5.4 152/232] io_uring: honor original task RLIMIT_FSIZE

From: Jens Axboe <axboe@...nel.dk>

commit 4ed734b0d0913e566a9d871e15d24eb240f269f7 upstream.

With the previous fixes for number of files open checking, I added some
debug code to see if we had other spots where we're checking rlimit()
against the async io-wq workers. The only one I found was file size
checking, which we should also honor.

During write and fallocate prep, store the max file size and override
that for the current ask if we're in io-wq worker context.

Cc: stable@...r.kernel.org # 5.1+
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>


---
 fs/io_uring.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -331,6 +331,7 @@ struct io_kiocb {
 #define REQ_F_ISREG		2048	/* regular file */
 #define REQ_F_MUST_PUNT		4096	/* must be punted even for NONBLOCK */
 #define REQ_F_TIMEOUT_NOSEQ	8192	/* no timeout sequence */
+	unsigned long		fsize;
 	u64			user_data;
 	u32			result;
 	u32			sequence;
@@ -1085,6 +1086,9 @@ static int io_prep_rw(struct io_kiocb *r
 	if (S_ISREG(file_inode(req->file)->i_mode))
 		req->flags |= REQ_F_ISREG;
 
+	if (force_nonblock)
+		req->fsize = rlimit(RLIMIT_FSIZE);
+
 	/*
 	 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
 	 * we know to async punt it even if it was opened O_NONBLOCK
@@ -1504,10 +1508,17 @@ static int io_write(struct io_kiocb *req
 		}
 		kiocb->ki_flags |= IOCB_WRITE;
 
+		if (!force_nonblock)
+			current->signal->rlim[RLIMIT_FSIZE].rlim_cur = req->fsize;
+
 		if (file->f_op->write_iter)
 			ret2 = call_write_iter(file, kiocb, &iter);
 		else
 			ret2 = loop_rw_iter(WRITE, file, kiocb, &iter);
+
+		if (!force_nonblock)
+			current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
+
 		if (!force_nonblock || ret2 != -EAGAIN) {
 			io_rw_done(kiocb, ret2);
 		} else {