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 C4EC728EB for ; Mon, 30 Jan 2023 13:54:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 29071C4339B; Mon, 30 Jan 2023 13:54:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675086884; bh=YJh0KEvg139heAIAZmWjn3YqiW+d/l96WNQNoNX/zVs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NWGzJSB/gb05088ruwNgwxRBdCKdmZ6iyBFpWcxgYfMVjb2xqYAq2I1z3HLrF1FL9 ZGi8UM/V9noyzi0HC1Ak4lbGk8QfrVlFoP6Ml7feUsT9biLFpphWV9zczpTn5B9WYP Zp46CwCbTa0fJUChMC+NfIkaLF3dppUj5yH5BpvE= 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 6.1 028/313] firmware: arm_scmi: Harden shared memory access in fetch_notification Date: Mon, 30 Jan 2023 14:47:43 +0100 Message-Id: <20230130134337.982240592@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230130134336.532886729@linuxfoundation.org> References: <20230130134336.532886729@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 9bae076cd4e3e3c3dc185cae829d80b2dddec86e ] A misbheaving SCMI platform firmware could reply with out-of-spec notifications, shorter than the mimimum size comprising a header. Fixes: d5141f37c42e ("firmware: arm_scmi: Add notifications support in transport layer") Signed-off-by: Cristian Marussi Link: https://lore.kernel.org/r/20221222183823.518856-4-cristian.marussi@arm.com Signed-off-by: Sudeep Holla Signed-off-by: Sasha Levin --- drivers/firmware/arm_scmi/shmem.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scmi/shmem.c b/drivers/firmware/arm_scmi/shmem.c index 135f8718000f..87b4f4d35f06 100644 --- a/drivers/firmware/arm_scmi/shmem.c +++ b/drivers/firmware/arm_scmi/shmem.c @@ -94,8 +94,10 @@ void shmem_fetch_response(struct scmi_shared_mem __iomem *shmem, void shmem_fetch_notification(struct scmi_shared_mem __iomem *shmem, size_t max_len, struct scmi_xfer *xfer) { + size_t len = ioread32(&shmem->length); + /* Skip only the length of header in shmem area i.e 4 bytes */ - xfer->rx.len = min_t(size_t, max_len, ioread32(&shmem->length) - 4); + xfer->rx.len = min_t(size_t, max_len, len > 4 ? len - 4 : 0); /* Take a copy to the rx buffer.. */ memcpy_fromio(xfer->rx.buf, shmem->msg_payload, xfer->rx.len); -- 2.39.0