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([2001:41d0:303:db6b::]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a35a55e9aasm229425455e9.5.2026.10.26.16.09.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Oct 2026 16:09:12 -0700 (PDT) From: Tristan Madani X-Google-Original-From: Tristan Madani To: Marius Cristea , Jonathan Cameron Cc: David Lechner , Nuno Sa , Andy Shevchenko , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, tristan@talencesecurity.com Subject: [PATCH] iio: adc: pac1934: validate ACPI _DSM return type and bounds Date: Mon, 26 Oct 2026 23:09:10 +0000 Message-ID: <20261026230910.2569782-1-tristan@talencesecurity.com> X-Mailer: git-send-email 2.47.3 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit pac1934_acpi_parse_channel_config() calls acpi_evaluate_dsm() four times to read channel configuration but does not validate the returned object type or array bounds: 1. No check that the returned object is ACPI_TYPE_PACKAGE. If firmware returns a different type, accessing rez->package.count and rez->package.elements on a non-package object produces unpredictable values. 2. The loop bounds use rez->package.count directly without capping to PAC1934_MAX_NUM_CHANNELS (4). A package with more elements than expected causes writes past the fixed-size labels[], shunts[], and active_channels[] arrays. 3. The bipolar and sample rate DSM calls access elements[0] without verifying package.count >= 1. Add ACPI_TYPE_PACKAGE validation after each acpi_evaluate_dsm() call, cap loop iterations to PAC1934_MAX_NUM_CHANNELS, and verify package count >= 1 before accessing elements[0]. Fixes: 0fb528c8255b ("iio: adc: adding support for PAC193x") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani --- drivers/iio/adc/pac1934.c | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/pac1934.c b/drivers/iio/adc/pac1934.c index de59dc27c4405..43c4705c27be7 100644 --- a/drivers/iio/adc/pac1934.c +++ b/drivers/iio/adc/pac1934.c @@ -1101,8 +1101,13 @@ static int pac1934_acpi_parse_channel_config(struct i2c_client *client, rez = acpi_evaluate_dsm(handle, &guid, 0, PAC1934_ACPI_GET_NAMES_AND_MOHMS_VALS, NULL); if (!rez) return -EINVAL; + if (rez->type != ACPI_TYPE_PACKAGE) { + ACPI_FREE(rez); + return -EINVAL; + } - for (i = 0; i < rez->package.count; i += 2) { + for (i = 0; i + 1 < rez->package.count && + i / 2 < PAC1934_MAX_NUM_CHANNELS; i += 2) { idx = i / 2; info->labels[idx] = devm_kmemdup(dev, rez->package.elements[i].string.pointer, @@ -1130,7 +1135,13 @@ static int pac1934_acpi_parse_channel_config(struct i2c_client *client, return 0; } - for (i = 0; i < rez->package.count; i++) { + if (rez->type != ACPI_TYPE_PACKAGE) { + ACPI_FREE(rez); + return -EINVAL; + } + + for (i = 0; i < rez->package.count && + i < PAC1934_MAX_NUM_CHANNELS; i++) { idx = i; info->shunts[idx] = rez->package.elements[i].integer.value; info->active_channels[idx] = (info->shunts[idx] != 0); @@ -1141,6 +1152,10 @@ static int pac1934_acpi_parse_channel_config(struct i2c_client *client, rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1934_ACPI_GET_BIPOLAR_SETTINGS, NULL); if (!rez) return -EINVAL; + if (rez->type != ACPI_TYPE_PACKAGE || rez->package.count < 1) { + ACPI_FREE(rez); + return -EINVAL; + } bi_dir_mask = rez->package.elements[0].integer.value; info->bi_dir[0] = ((bi_dir_mask & (1 << 3)) | (bi_dir_mask & (1 << 7))) != 0; @@ -1153,6 +1168,10 @@ static int pac1934_acpi_parse_channel_config(struct i2c_client *client, rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1934_ACPI_GET_SAMP, NULL); if (!rez) return -EINVAL; + if (rez->type != ACPI_TYPE_PACKAGE || rez->package.count < 1) { + ACPI_FREE(rez); + return -EINVAL; + } info->sample_rate_value = rez->package.elements[0].integer.value; -- 2.47.3