From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE1875172F5; Wed, 30 Sep 2026 18:25:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790792711; cv=none; b=StDiR52YlvcqVf2puq0p3LI8ojTFI899TLlu+SoLkbUqj8DqdSD8je1oKYNZuj0OiSsAHYHxeTK/LOyIwjnRgobyzJtkW+LtlbwFSDtvg9lI6bCQVSidstUXULu0pB3VsFa3LjpeO6OwJZp+5/sVVNHr83UY356bJjsO4QOgnTo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790792711; c=relaxed/simple; bh=cShzxRHcOBV0haL3fPYAJcgqwm2ImjuNxQ2Jw6ydxdI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PMVJpEqnSGhqacTPz08OS15b4ptnge/jO+9HTrXLDZbPHVgdOPbvi5/kpHfsCBjhfPqBSJprWSZbdVdzywgZ58rVZ5o+siOUNr9guKjsMYYEJZaa5y2qEzdwtePBWTVWXNbvpzTjU2RVg10I9GUUvwHKas/W1rA3H8iZl2iE62E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LTp0J6za; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LTp0J6za" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E49A1F0089A; Wed, 30 Sep 2026 18:25:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790792709; bh=8Cf37mxC1gGuNmpClDyNGnXvr41PXfm0w/TIKPWfUTk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=LTp0J6zaVg2Yz/vf4p56MTjrBRNNSNZOTi0RPiKt02Zk1PQ5c0zAaXzr6JNSGf0wu F/G41DA7NBbYpiCYrtKkS2iez0+GQzGDVZbZu1CpOK+u9GDFkEcQItbne7T2nJ4Blb h9UhnKaf0jz3meXxKN56KP5GRHu2Sqg9aCWC7u00= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dongliang Qin , Allison Henderson , Paolo Abeni Subject: [PATCH 5.15 707/752] rds: ib: Clear the sg list when mapping an MR fails Date: Wed, 30 Sep 2026 17:29:37 +0200 Message-ID: <20260930152413.529298290@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dongliang Qin commit 58eb1b3325edac42dc6df72c80962bd53a3c8ca7 upstream. rds_ib_map_frmr() stores the caller's scatterlist in the MR before DMA mapping and registration can fail. On failure, __rds_rdma_map() unpins the pages and frees the scatterlist, but rds_ib_free_frmr() can still return the MR to the pool with the stale pointer set. This leaves the pool with a dangling scatterlist and can lead to local privilege escalation. KASAN detects the resulting use-after-free when the MR is later torn down: BUG: KASAN: slab-use-after-free in __rds_ib_teardown_mr Read of size 8 Call Trace: __rds_ib_teardown_mr rds_ib_unreg_frmr rds_ib_flush_mr_pool rds_ib_flush_mrs rds_free_mr rds_setsockopt Store the scatterlist in the MR only after DMA mapping succeeds. If DMA mapping fails, return directly while the MR fields remain clear; the caller keeps ownership of the scatterlist and its pinned pages. If a later registration step fails, unmap the scatterlist and clear the MR fields before returning. Fixes: 1659185fb4d0 ("RDS: IB: Support Fastreg MR (FRMR) memory registration mode") Cc: stable@vger.kernel.org Signed-off-by: Dongliang Qin Reviewed-by: Allison Henderson Link: https://patch.msgid.link/20260922031546.3874605-1-cccccccccccc777777@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/rds/ib_frmr.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) --- a/net/rds/ib_frmr.c +++ b/net/rds/ib_frmr.c @@ -204,19 +204,16 @@ static int rds_ib_map_frmr(struct rds_ib */ rds_ib_teardown_mr(ibmr); - ibmr->sg = sg; - ibmr->sg_len = sg_len; - ibmr->sg_dma_len = 0; frmr->sg_byte_len = 0; - WARN_ON(ibmr->sg_dma_len); - ibmr->sg_dma_len = ib_dma_map_sg(dev, ibmr->sg, ibmr->sg_len, + ibmr->sg_dma_len = ib_dma_map_sg(dev, sg, sg_len, DMA_BIDIRECTIONAL); if (unlikely(!ibmr->sg_dma_len)) { pr_warn("RDS/IB: %s failed!\n", __func__); return -EBUSY; } - frmr->sg_byte_len = 0; + ibmr->sg = sg; + ibmr->sg_len = sg_len; frmr->dma_npages = 0; len = 0; @@ -264,6 +261,8 @@ out_unmap: ib_dma_unmap_sg(rds_ibdev->dev, ibmr->sg, ibmr->sg_len, DMA_BIDIRECTIONAL); ibmr->sg_dma_len = 0; + ibmr->sg = NULL; + ibmr->sg_len = 0; return ret; }