Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754007Ab2FSCSU (ORCPT ); Mon, 18 Jun 2012 22:18:20 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:50286 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752512Ab2FSCSQ (ORCPT ); Mon, 18 Jun 2012 22:18:16 -0400 From: Anton Vorontsov To: Greg Kroah-Hartman , Kees Cook , Colin Cross , Tony Luck Cc: Arnd Bergmann , John Stultz , Shuah Khan , arve@android.com, Rebecca Schultz Zavin , Jesper Juhl , Randy Dunlap , Stephen Boyd , Thomas Meyer , Andrew Morton , Marco Stornelli , WANG Cong , linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com Subject: [PATCH 4/7] pstore/ram_core: Better ECC size checking Date: Mon, 18 Jun 2012 19:15:53 -0700 Message-Id: <1340072156-6225-4-git-send-email-anton.vorontsov@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <20120619021050.GA19387@lizard> References: <20120619021050.GA19387@lizard> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2372 Lines: 71 - Instead of exploiting unsigned overflows (which doesn't work for all sizes), use straightforward checking for ECC total size not exceeding initial buffer size; - Printing overflowed buffer_size is not informative. Instead, print ecc_size and buffer_size; - No need for buffer_size argument in persistent_ram_init_ecc(), we can address prz->buffer_size directly. Signed-off-by: Anton Vorontsov --- fs/pstore/ram_core.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index f62ebf2..a5a7b13 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -171,12 +171,12 @@ static void persistent_ram_ecc_old(struct persistent_ram_zone *prz) } } -static int persistent_ram_init_ecc(struct persistent_ram_zone *prz, - size_t buffer_size) +static int persistent_ram_init_ecc(struct persistent_ram_zone *prz) { int numerr; struct persistent_ram_buffer *buffer = prz->buffer; int ecc_blocks; + size_t ecc_total; if (!prz->ecc) return 0; @@ -187,14 +187,14 @@ static int persistent_ram_init_ecc(struct persistent_ram_zone *prz, prz->ecc_poly = 0x11d; ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size); - prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size; - - if (prz->buffer_size > buffer_size) { - pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n", - buffer_size, prz->buffer_size); + ecc_total = (ecc_blocks + 1) * prz->ecc_size; + if (ecc_total >= prz->buffer_size) { + pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n", + __func__, prz->ecc_size, ecc_total, prz->buffer_size); return -EINVAL; } + prz->buffer_size -= ecc_total; prz->par_buffer = buffer->data + prz->buffer_size; prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size; @@ -397,7 +397,7 @@ static int __devinit persistent_ram_post_init(struct persistent_ram_zone *prz, prz->ecc = ecc; - ret = persistent_ram_init_ecc(prz, prz->buffer_size); + ret = persistent_ram_init_ecc(prz); if (ret) return ret; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/