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 D89FD3D3D03; Wed, 8 Apr 2026 14:34:06 +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=1775658846; cv=none; b=kg1L1XlhV8k7rUHPCYKN288wSADOcpk//42wZJRyNkc1wkUkdgJBrYexR+4EoTIEsWIFoxpOJ+RhyO7y722KNV/X6kJHFR3JXaFoa+Ln7E/tJ/j+9fOnyZ4Cu6bAegyno5xLGD8VrFmICeuRpcIw3YBLaEgyqCBu/Zr2fr0XoLQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775658846; c=relaxed/simple; bh=eqeiAcPNJoTSStYt75yr4ts6fdSk7s1G6BqcIV2sk3A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CChm55ealw3fWp4xUv16KOfsiDwaW4FRb9wf/uFTygOP1JNBQ6B0+TMXa9vTNaXM0KcZVAYR8c+2OBv3R0lXowHvix2pdKruYoNTCxdW9C4ErsH7By3ONiazXWD81CSB5Mz93pJRoVgvPn/YEZmqQzPnvCbc15CgbUh7aR2AZ+8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=p+09DSAs; 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="p+09DSAs" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52616C2BC87; Wed, 8 Apr 2026 14:34:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775658846; bh=eqeiAcPNJoTSStYt75yr4ts6fdSk7s1G6BqcIV2sk3A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p+09DSAsZv+juc5pNeg+j9ihUj/dDi0Hrufvk3YCYrzYs2aJzJ21EKC85zfI5wXL3 DN7NP9D6R+cOIEMrRkeTyF9gT7cmFBwaLtABrQkC+v7Rqz5J1tqZlaETtb4jtkdzc5 GHYQNPACKEUdqY42xF3FuVD/9blljao8uwxa0SfNbRAfP4U5L50A1uGGgltloirsNB 7SujRG52zbKb1KkaJd/ah5Ga58sKU5YJ8ABbmF9BkAH4tgFYFyl1ZvyBlUleqZNbKW OqW7vXCi5VOybUgyQ/Qh8XyoEzCloiyjnPn2Lr0g3kcyH9QOQjFndTo/MHKgZbJ2nj DY+ykkLl3Yj9g== From: Tycho Andersen To: Tom Lendacky , John Allen , Herbert Xu , "David S. Miller" , Ashish Kalra Cc: "Borislav Petkov (AMD)" , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Brijesh Singh , Michael Roth , Alexey Kardashevskiy , Dan Williams , "Tycho Andersen (AMD)" Subject: [PATCH v1 2/4] crypto/ccp: Fix snp_filter_reserved_mem_regions() off-by-one Date: Wed, 8 Apr 2026 08:32:57 -0600 Message-ID: <20260408143259.602767-3-tycho@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260408143259.602767-1-tycho@kernel.org> References: <20260408143259.602767-1-tycho@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Tycho Andersen (AMD)" Sashiko notes: > regarding the bounds check in snp_filter_reserved_mem_regions() > called via walk_iomem_res_desc(): does the check > if ((range_list->num_elements * 16 + 8) > PAGE_SIZE) > allow an off-by-one heap buffer overflow? > > If range_list->num_elements is 255, 255 * 16 + 8 = 4088, which is <= 4096. > Writing range->base (8 bytes) fills 4088-4095, but writing range->page_count > (4 bytes) would write to 4096-4099, overflowing the kzalloc-allocated > PAGE_SIZE buffer. Fix this by accounting for the entry about to be written to, in addition to the entries that are already allocated. Fixes: 1ca5614b84ee ("crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP") Reported-by: Sashiko Assisted-by: Gemini:gemini-3.1-pro-preview Link: https://sashiko.dev/#/patchset/20260324161301.1353976-1-tycho%40kernel.org Signed-off-by: Tycho Andersen (AMD) --- drivers/crypto/ccp/sev-dev.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index 939fa8aa155c..e87efcff8df2 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -1328,10 +1328,11 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg) size_t size; /* - * Ensure the list of HV_FIXED pages that will be passed to firmware - * do not exceed the page-sized argument buffer. + * Ensure the list of HV_FIXED pages passed to the firmware including + * the one about to be written to do not exceed the page-sized argument + * buffer. */ - if ((range_list->num_elements * sizeof(struct sev_data_range) + + if (((range_list->num_elements + 1) * sizeof(struct sev_data_range) + sizeof(struct sev_data_range_list)) > PAGE_SIZE) return -E2BIG; -- 2.53.0