From patchwork Wed Mar 11 07:43:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 11430993 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 403E21800 for ; Wed, 11 Mar 2020 07:43:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 29F7A2146E for ; Wed, 11 Mar 2020 07:43:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728378AbgCKHn3 (ORCPT ); Wed, 11 Mar 2020 03:43:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:48200 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728126AbgCKHn3 (ORCPT ); Wed, 11 Mar 2020 03:43:29 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id DA698AEAC; Wed, 11 Mar 2020 07:43:27 +0000 (UTC) From: Takashi Iwai To: Jonathan Cameron , linux-iio@vger.kernel.org Subject: [PATCH 1/2] iio: core: Use scnprintf() for avoiding potential buffer overflow Date: Wed, 11 Mar 2020 08:43:24 +0100 Message-Id: <20200311074325.7922-2-tiwai@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200311074325.7922-1-tiwai@suse.de> References: <20200311074325.7922-1-tiwai@suse.de> Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Since snprintf() returns the would-be-output size instead of the actual output size, the succeeding calls may go beyond the given buffer limit. Fix it by replacing with scnprintf(). Signed-off-by: Takashi Iwai --- drivers/iio/industrialio-core.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index 65ff0d067018..197006b5d5c2 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -559,46 +559,46 @@ static ssize_t __iio_format_value(char *buf, size_t len, unsigned int type, switch (type) { case IIO_VAL_INT: - return snprintf(buf, len, "%d", vals[0]); + return scnprintf(buf, len, "%d", vals[0]); case IIO_VAL_INT_PLUS_MICRO_DB: scale_db = true; /* fall through */ case IIO_VAL_INT_PLUS_MICRO: if (vals[1] < 0) - return snprintf(buf, len, "-%d.%06u%s", abs(vals[0]), + return scnprintf(buf, len, "-%d.%06u%s", abs(vals[0]), -vals[1], scale_db ? " dB" : ""); else - return snprintf(buf, len, "%d.%06u%s", vals[0], vals[1], + return scnprintf(buf, len, "%d.%06u%s", vals[0], vals[1], scale_db ? " dB" : ""); case IIO_VAL_INT_PLUS_NANO: if (vals[1] < 0) - return snprintf(buf, len, "-%d.%09u", abs(vals[0]), + return scnprintf(buf, len, "-%d.%09u", abs(vals[0]), -vals[1]); else - return snprintf(buf, len, "%d.%09u", vals[0], vals[1]); + return scnprintf(buf, len, "%d.%09u", vals[0], vals[1]); case IIO_VAL_FRACTIONAL: tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]); tmp1 = vals[1]; tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1); - return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); + return scnprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); case IIO_VAL_FRACTIONAL_LOG2: tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]); tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1); - return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); + return scnprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); case IIO_VAL_INT_MULTIPLE: { int i; int l = 0; for (i = 0; i < size; ++i) { - l += snprintf(&buf[l], len - l, "%d ", vals[i]); + l += scnprintf(&buf[l], len - l, "%d ", vals[i]); if (l >= len) break; } return l; } case IIO_VAL_CHAR: - return snprintf(buf, len, "%c", (char)vals[0]); + return scnprintf(buf, len, "%c", (char)vals[0]); default: return 0; } @@ -669,10 +669,10 @@ static ssize_t iio_format_avail_list(char *buf, const int *vals, if (len >= PAGE_SIZE) return -EFBIG; if (i < length - 1) - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, " "); else - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, "\n"); if (len >= PAGE_SIZE) return -EFBIG; @@ -685,10 +685,10 @@ static ssize_t iio_format_avail_list(char *buf, const int *vals, if (len >= PAGE_SIZE) return -EFBIG; if (i < length / 2 - 1) - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, " "); else - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, "\n"); if (len >= PAGE_SIZE) return -EFBIG; @@ -712,10 +712,10 @@ static ssize_t iio_format_avail_range(char *buf, const int *vals, int type) if (len >= PAGE_SIZE) return -EFBIG; if (i < 2) - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, " "); else - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, "]\n"); if (len >= PAGE_SIZE) return -EFBIG; @@ -728,10 +728,10 @@ static ssize_t iio_format_avail_range(char *buf, const int *vals, int type) if (len >= PAGE_SIZE) return -EFBIG; if (i < 2) - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, " "); else - len += snprintf(buf + len, PAGE_SIZE - len, + len += scnprintf(buf + len, PAGE_SIZE - len, "]\n"); if (len >= PAGE_SIZE) return -EFBIG;