From patchwork Wed Jun 14 21:56:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thadeu Lima de Souza Cascardo X-Patchwork-Id: 1795109 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=canonical.com header.i=@canonical.com header.a=rsa-sha256 header.s=20210705 header.b=OMgCmqbN; dkim-atps=neutral Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4QhK775Vcpz20X4 for ; Thu, 15 Jun 2023 07:58:27 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1q9YVS-0002GG-Hc; Wed, 14 Jun 2023 21:58:22 +0000 Received: from smtp-relay-canonical-1.internal ([10.131.114.174] helo=smtp-relay-canonical-1.canonical.com) by huckleberry.canonical.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1q9YVP-0002Ft-O9 for kernel-team@lists.ubuntu.com; Wed, 14 Jun 2023 21:58:19 +0000 Received: from localhost.localdomain (1.general.cascardo.us.vpn [10.172.70.58]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id B0BD53F178 for ; Wed, 14 Jun 2023 21:58:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1686779899; bh=dLmvOusppucEEh7lujo5sNID4r10vSZoYZyf+QTSaZc=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=OMgCmqbN0w86JWaknIKOdjyqbv/k4B5VsrEL9st7MkLFkWwRy0sbOHztwqtFl7WCC b7qGh0T7qZupGfEtIpV/8ILuod6yyBh5D77E+agIkAFErlECCgX7yJT+1T/af20bnf 4fsZOP/ndRtxaMR+x3DW6fkgOAfeqSU+jfJSKK5kQVSNqEEghgKSjiK1HljuRxv+pY 1ZJi74dnFDV9raL7m5yknl5ay1pbFxih5PRx7OEoITmXOIXX+uzf/rKx3H30IeU37M PVSaM/VWDBPsjHdOGlah6fOuyKTGicjw79X4kIwo8ytQ0dtCE8QqiIfQQb8ARGjmyO lHM3aDmX1hCnw== From: Thadeu Lima de Souza Cascardo To: kernel-team@lists.ubuntu.com Subject: [SRU OEM-6.0 1/4] io_uring: get rid of double locking Date: Wed, 14 Jun 2023 18:56:04 -0300 Message-Id: <20230614215607.2177733-2-cascardo@canonical.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230614215607.2177733-1-cascardo@canonical.com> References: <20230614215607.2177733-1-cascardo@canonical.com> MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Pavel Begunkov We don't need to take both uring_locks at once, msg_ring can be split in two parts, first getting a file from the filetable of the first ring and then installing it into the second one. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/a80ecc2bc99c3b3f2cf20015d618b7c51419a797.1670384893.git.asml.silence@gmail.com Signed-off-by: Jens Axboe (cherry picked from commit 11373026f2960390d5e330df4e92735c4265c440) CVE-2023-2430 Signed-off-by: Thadeu Lima de Souza Cascardo --- io_uring/msg_ring.c | 85 ++++++++++++++++++++++++++------------------- io_uring/msg_ring.h | 1 + io_uring/opdef.c | 1 + 3 files changed, 51 insertions(+), 36 deletions(-) diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c index 90d2fc6fd80e..e575237e8a97 100644 --- a/io_uring/msg_ring.c +++ b/io_uring/msg_ring.c @@ -15,6 +15,7 @@ struct io_msg { struct file *file; + struct file *src_file; u64 user_data; u32 len; u32 cmd; @@ -23,6 +24,17 @@ struct io_msg { u32 flags; }; +void io_msg_ring_cleanup(struct io_kiocb *req) +{ + struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); + + if (WARN_ON_ONCE(!msg->src_file)) + return; + + fput(msg->src_file); + msg->src_file = NULL; +} + static int io_msg_ring_data(struct io_kiocb *req) { struct io_ring_ctx *target_ctx = req->file->private_data; @@ -37,17 +49,13 @@ static int io_msg_ring_data(struct io_kiocb *req) return -EOVERFLOW; } -static void io_double_unlock_ctx(struct io_ring_ctx *ctx, - struct io_ring_ctx *octx, +static void io_double_unlock_ctx(struct io_ring_ctx *octx, unsigned int issue_flags) { - if (issue_flags & IO_URING_F_UNLOCKED) - mutex_unlock(&ctx->uring_lock); mutex_unlock(&octx->uring_lock); } -static int io_double_lock_ctx(struct io_ring_ctx *ctx, - struct io_ring_ctx *octx, +static int io_double_lock_ctx(struct io_ring_ctx *octx, unsigned int issue_flags) { /* @@ -60,17 +68,28 @@ static int io_double_lock_ctx(struct io_ring_ctx *ctx, return -EAGAIN; return 0; } + mutex_lock(&octx->uring_lock); + return 0; +} - /* Always grab smallest value ctx first. We know ctx != octx. */ - if (ctx < octx) { - mutex_lock(&ctx->uring_lock); - mutex_lock(&octx->uring_lock); - } else { - mutex_lock(&octx->uring_lock); - mutex_lock(&ctx->uring_lock); +static struct file *io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); + struct io_ring_ctx *ctx = req->ctx; + struct file *file = NULL; + unsigned long file_ptr; + int idx = msg->src_fd; + + io_ring_submit_lock(ctx, issue_flags); + if (likely(idx < ctx->nr_user_files)) { + idx = array_index_nospec(idx, ctx->nr_user_files); + file_ptr = io_fixed_file_slot(&ctx->file_table, idx)->file_ptr; + file = (struct file *) (file_ptr & FFS_MASK); + if (file) + get_file(file); } - - return 0; + io_ring_submit_unlock(ctx, issue_flags); + return file; } static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) @@ -78,34 +97,27 @@ static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) struct io_ring_ctx *target_ctx = req->file->private_data; struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg); struct io_ring_ctx *ctx = req->ctx; - unsigned long file_ptr; - struct file *src_file; + struct file *src_file = msg->src_file; int ret; if (target_ctx == ctx) return -EINVAL; + if (!src_file) { + src_file = io_msg_grab_file(req, issue_flags); + if (!src_file) + return -EBADF; + msg->src_file = src_file; + req->flags |= REQ_F_NEED_CLEANUP; + } - ret = io_double_lock_ctx(ctx, target_ctx, issue_flags); - if (unlikely(ret)) - return ret; - - ret = -EBADF; - if (unlikely(msg->src_fd >= ctx->nr_user_files)) - goto out_unlock; - - msg->src_fd = array_index_nospec(msg->src_fd, ctx->nr_user_files); - file_ptr = io_fixed_file_slot(&ctx->file_table, msg->src_fd)->file_ptr; - if (!file_ptr) - goto out_unlock; - - src_file = (struct file *) (file_ptr & FFS_MASK); - get_file(src_file); + if (unlikely(io_double_lock_ctx(target_ctx, issue_flags))) + return -EAGAIN; ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd); - if (ret < 0) { - fput(src_file); + if (ret < 0) goto out_unlock; - } + msg->src_file = NULL; + req->flags &= ~REQ_F_NEED_CLEANUP; if (msg->flags & IORING_MSG_RING_CQE_SKIP) goto out_unlock; @@ -119,7 +131,7 @@ static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags) if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0, true)) ret = -EOVERFLOW; out_unlock: - io_double_unlock_ctx(ctx, target_ctx, issue_flags); + io_double_unlock_ctx(target_ctx, issue_flags); return ret; } @@ -130,6 +142,7 @@ int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) if (unlikely(sqe->buf_index || sqe->personality)) return -EINVAL; + msg->src_file = NULL; msg->user_data = READ_ONCE(sqe->off); msg->len = READ_ONCE(sqe->len); msg->cmd = READ_ONCE(sqe->addr); diff --git a/io_uring/msg_ring.h b/io_uring/msg_ring.h index fb9601f202d0..3987ee6c0e5f 100644 --- a/io_uring/msg_ring.h +++ b/io_uring/msg_ring.h @@ -2,3 +2,4 @@ int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags); +void io_msg_ring_cleanup(struct io_kiocb *req); diff --git a/io_uring/opdef.c b/io_uring/opdef.c index 3b15cdb6dbbc..34528331392f 100644 --- a/io_uring/opdef.c +++ b/io_uring/opdef.c @@ -434,6 +434,7 @@ const struct io_op_def io_op_defs[] = { .name = "MSG_RING", .prep = io_msg_ring_prep, .issue = io_msg_ring, + .cleanup = io_msg_ring_cleanup, }, [IORING_OP_FSETXATTR] = { .needs_file = 1,