From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 543233AEB2D; Wed, 13 May 2026 18:51:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778698280; cv=none; b=u+495YtpaxgtdAUxFNRR4nIgwvhk4c1GE/8YpW7FhsIY97vXCfTDB4SG4bVFnpiZ1QXFwPiPR2GsQhrr22bo6BRUhl5lh1mLrDT7kGpsxWRI6qhDIepsAtP8RiFOYEF4Lm5lvjwVCXzAcbVkcoPW9nhWnxIB6Dr9OGAgeaamsZc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778698280; c=relaxed/simple; bh=lhT7NJBZvan2O6Wc05lY2i0l2fScOUH585qfonxfZak=; h=From:To:Cc:In-Reply-To:References:Subject:Message-Id:Date: MIME-Version:Content-Type; b=oZMo5yxCT2/gKRw4D0nX8DpZB2ijzVBd2n3y3wb5/Ls60iRO3eCM5nZ8JaVUaHDv8ItC5YfUvthgVGUqfWnPz8qGIt4fqbsUYs5clYz/8qXrpTJw6HwHIqQ4hr6vq7zFM/hplnciPFZwiUlZdsMCaF+f1R3J5wfB6/4SGg8mes4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R5Zs+AKh; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R5Zs+AKh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5CF44C2BCB7; Wed, 13 May 2026 18:51:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778698280; bh=lhT7NJBZvan2O6Wc05lY2i0l2fScOUH585qfonxfZak=; h=From:To:Cc:In-Reply-To:References:Subject:Date:From; b=R5Zs+AKhMrUXeT4vGc/9h8QGsVEodu9ZK5NVq7RgxgdFwUFyFME6LzIxRC93H5gad wFinXc/J5y9nFxa3OUPRdLKJUWh5or9CiT8A7T3HHea7HhVoAPnR9cr2lskw7MRFAd NagSeua/cnqLR1gLpgW/qV/eTJAHxSRjM7QuuduzVk7NWfZyKMORAaZ2SeAEhVa7FK ElkA+kgDFa1ihFYertbg/eKu0IuYVQBYHEQB8BhD3HZjMlwpJqH3ribAOkt/96sl98 aTn/7zDozPNXp3Fi9F4uTtSLNvlUBY/D/uOiIiyjVZYbXMOx/tn7EeJyzHRgIJ7+qE ZYdyj2sAM2YFg== From: Leon Romanovsky To: security@kernel.org, pomzm67@gmail.com Cc: selvin.xavier@broadcom.com, kalesh-anakkur.purayil@broadcom.com, jgg@ziepe.ca, eddie.wai@broadcom.com, somnath.kotur@broadcom.com, sriharsha.basavapatna@broadcom.com, devesh.sharma@broadcom.com, dledford@redhat.com, gregkh@linuxfoundation.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, Lord Ulf Henrik Holmberg In-Reply-To: <20260509084011.11971-1-pomzm67@gmail.com> References: <20260509084011.11971-1-pomzm67@gmail.com> Subject: Re: [PATCH] RDMA/bnxt_re: zero shared page before exposing to userspace Message-Id: <177869827695.2371282.12223364694168712496.b4-ty@kernel.org> Date: Wed, 13 May 2026 14:51:16 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailer: b4 0.15-dev-18f8f On Sat, 09 May 2026 10:40:11 +0200, pomzm67@gmail.com wrote: > bnxt_re_alloc_ucontext() allocates uctx->shpg via > __get_free_page(GFP_KERNEL). The buddy allocator does not zero pages > without __GFP_ZERO, so the page contains stale kernel data from > whatever object most recently freed it. > > The page is then mapped into userspace via vm_insert_page() under > BNXT_RE_MMAP_SH_PAGE in bnxt_re_mmap(). The driver only ever writes > 4 bytes (a u32 AVID) at offset BNXT_RE_AVID_OFFT (0x10) inside > bnxt_re_create_ah(); the remaining 4092 bytes of the page are exposed > to userspace unsanitised, leaking kernel memory contents. > > [...] Applied, thanks! [1/1] RDMA/bnxt_re: zero shared page before exposing to userspace (no commit info) Best regards, -- Leon Romanovsky