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 5CEE633CE for ; Mon, 30 Jan 2023 14:20:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9EB7C433EF; Mon, 30 Jan 2023 14:20:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675088415; bh=oe1vOrC3J2wIMZvCNfvW0PTVXGscd+F91npwP/L0YFk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oxiNA6lXDgaL0VCf0TKnkofJ8KxtdBWUzmveelDTayBmUasiSHSMY290oiEyITN9P LOQEFIeAYmubegdaT9uQyJEQCwGQE51xey/QlfA054gntDA+CFKWXLdUjO/IsdXqmq btWbTLRXp83Fpw0sb/YiX5ev6plvusXFouiq3nOM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Cristian Marussi , Sudeep Holla , Sasha Levin Subject: [PATCH 5.10 012/143] firmware: arm_scmi: Harden shared memory access in fetch_response Date: Mon, 30 Jan 2023 14:51:09 +0100 Message-Id: <20230130134307.393121517@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134306.862721518@linuxfoundation.org> References: <20230130134306.862721518@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Cristian Marussi [ Upstream commit ad78b81a1077f7d956952cd8bdfe1e61504e3eb8 ] A misbheaving SCMI platform firmware could reply with out-of-spec messages, shorter than the mimimum size comprising a header and a status field. Harden shmem_fetch_response to properly truncate such a bad messages. Fixes: 5c8a47a5a91d ("firmware: arm_scmi: Make scmi core independent of the transport type") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221222183823.518856-3-cristian.marussi@arm.com Signed-off-by: Sudeep Holla Signed-off-by: Sasha Levin --- drivers/firmware/arm_scmi/shmem.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c index 0e3eaea5d852..415ef7df8fc3 100644 --- a/drivers/firmware/arm_scmi/shmem.c +++ b/drivers/firmware/arm_scmi/shmem.c @@ -58,10 +58,11 @@ u32 shmem_read_header(struct scmi_shared_mem __iomem *shmem) void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem, struct scmi_xfer *xfer) { + size_t len = ioread32(&shmem->length); + xfer->hdr.status = ioread32(shmem->msg_payload); /* Skip the length of header and status in shmem area i.e 8 bytes */ - xfer->rx.len = min_t(size_t, xfer->rx.len, - ioread32(&shmem->length) - 8); + xfer->rx.len = min_t(size_t, xfer->rx.len, len > 8 ? len - 8 : 0); /* Take a copy to the rx buffer.. */ memcpy_fromio(xfer->rx.buf, shmem->msg_payload + 4, xfer->rx.len); -- 2.39.0