From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f48.google.com (mail-ej1-f48.google.com [209.85.218.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9794A217723 for ; Sun, 23 Aug 2026 04:52:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787460737; cv=none; b=d/S0LudzUThiMwHlFP/uIdNG3AlfKfdcWSUghVSdLm4J/a1dM4+zVarRwYJlFXw9W/1/gdyl7e0WY3hejwgDji/C0JcGJLcEfqeSIeY+VrplKwz+pCuaKg7Sejv0Rt2ZdYx/BbEGDkhkqFf8NJOm7MXAE9hxwpdptXN6qeYN0+g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787460737; c=relaxed/simple; bh=CRoIahk0zUJFCd/Gr3T4No9Q6gsYfuKWWIpbMSivG44=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=QSRAq0zrq2izJP0lXwa/Qvtba7vd1EMWruNHG7pg6KCL9sKabXnUtD+rK9Cr2ff/+u6xx0Olq4ipiyXceeaUscc/RW9FuSLHlzGsUE02zlUFUbOsUvd+q4WrmboemMJjANReOCAVfknJSo68g9YVEVn6DDGxKjrPrV8qLbjRi8A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Gqfy6nqu; arc=none smtp.client-ip=209.85.218.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Gqfy6nqu" Received: by mail-ej1-f48.google.com with SMTP id a640c23a62f3a-c160420289bso349671966b.0 for ; Sat, 22 Aug 2026 21:52:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787460734; x=1788065534; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=I0Bzy6U0wqPie5F2fLgX6BpcIVEHFkLwygimH93TRcA=; b=Gqfy6nquqrKu4qBHE+Twy+f5JsusKVpN6+jwkPRg2lVFVD/SsFG9jbMKu9VPK4CoYl wdC+xO8SXS7qiXSwSDzMAJMRh3ghIXPgNBJLpvZn27maFpm3LxWZyMHavHNDxYX+Sc0k Bmxn0gckGoyi+tmhxSRSY4V89wt9oXs8tcOI2UEZEVRZ6ERPntP5M00uYPaWkjwE8Xgk vCmUPY7ybIvwcRgUKAULAstHVC5nWRlVLPqmHX8IBJvwTYZ13bV96JdtnjU29xS4Vz4G FKVgEsPaIj21hx9gMSuiikqkGWEtwaJYfzCPzuXc2QC613SjY5YJoofRVX2QPuWOi0OD lTcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787460734; x=1788065534; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=I0Bzy6U0wqPie5F2fLgX6BpcIVEHFkLwygimH93TRcA=; b=gqPQyyqCiUMyCj5YWTrDmVwuAnl1H0i0t+qkK918/DuJn4dt6Rx3IapLDVicIgW042 JDK8HIvWDZWYlFro9IdEJ4DJ5URGY2fQbNX15IcPREBWI3iUUyubtpHBSOTwFFqvDq+Y tbayuxhM/3u0SyUw74vttP2Dn+S2Bk8i0IymfgAfqnXYND3xcUt3rRLD7T0K+iDXExOO 9vfNdoKbZxmczmVv+zwYGEK4/qqIfm5yo1CJ8YkqLmnX4GmZ0gBdb3jHxYn43pb8i0L7 noNj6+01xjJ6mjhlX/+wEG+Fn9rIoGStb8+hzD4cPZOxUYcc7bfaQ//McI9KM9AV8X+n Y22Q== X-Forwarded-Encrypted: i=1; AHgh+Rq7Gt9py7W6Z2gtdigr0mhL8iTzCiE2Q80fXvOV/jl5lxvxDj3xMeFWqGezUVVON7jHHH1+AsRi1/csab0=@vger.kernel.org X-Gm-Message-State: AFuF++m38N42r5S0DA5MqI6vDaLzXNlHAImiynh0K/l9A4ng9gNYqAhf dYYM13pEmzDXX0Zxo7qCn0zzGuqArq8jr4yOa36BOkaM7mC95fPcKKvg X-Gm-Gg: AR+sD10cL5EARDRmZ6eSujhp5R+YW7ZxquetPtgqpEm74gbCTUclblEY7tzuwe6TwQD Coe9EanfSjGPAwb977x2QQPZdJK4d9UuHRUWs+7SSVFlUHylBKLRW7HtR5LY8zXr5dHvkKhbzuB 9RXaR8NlpgqZbS6V4XelnuxyGHly09/XgEMeTp5gm28J/KzKAbe6PL0UdR2Qt4TozjrF6ej+OSC gljaEv6/KgqFRRJnTIj5nio1iMNYyDNojYg4iwYMBhNG8tiYjdnM8OSy4YGtBYFtqbROj7gDdQs bjs/APdr5m/y+eTzeghSRNiyA1CaCk5+ivL1vIy+u+iPHZMWJiR90NNyuIQxvhkQlWeuYovq/10 qcSHUbNEMK+IIaBaqOHcAr5d5zVcdSJ9hDvL+Q/QILIaDy3VCQrfOFRByduXv+7e0oAdafA0chD SoeG8AgxugaffWzswg/1BuY47P2zq7gsN0k0Rc4G6eSIkq+yWT6vq77hijAgmJ5MTqrXe2n0Mse Co= X-Received: by 2002:a17:907:1c1f:b0:c20:31d1:a899 with SMTP id a640c23a62f3a-c246a4ad97emr2015393366b.4.1787460733587; Sat, 22 Aug 2026 21:52:13 -0700 (PDT) Received: from localhost.localdomain ([196.235.129.19]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c24962a3c13sm652368866b.26.2026.08.22.21.52.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 Aug 2026 21:52:12 -0700 (PDT) From: Salah Triki To: Michael Hennerich , =?UTF-8?q?Nuno=20S=C3=A1?= , Jonathan Cameron , David Lechner , Andy Shevchenko , linux-iio@vger.kernel.org, linux@analog.com, linux-kernel@vger.kernel.org Cc: Salah Triki Subject: [PATCH v2] iio: adc: ad4030: fix invalid oversampling_ratio validation Date: Sun, 23 Aug 2026 05:52:05 +0100 Message-ID: <20260823045205.25554-1-salah.triki@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ad4030_set_avg_frame_len() computes avg_log2 = ilog2(avg_val) before validating avg_val, and the subsequent range check only rejects negative values or values above the maximum supported OSR. It does not reject avg_val == 0, nor values that are not exact powers of 2. - avg_val == 0 passes the check (0 is not < 0 and not > max), so ilog2(0) is called with an undefined/garbage result. - Non-power-of-2 values (e.g. avg_val == 3) also pass the check and silently get rounded down by ilog2() to the nearest lower power of 2, so userspace can write a value to the oversampling_ratio sysfs attribute that does not match what actually gets programmed into hardware, without any error being reported. Only powers of 2 in [1, 65536] are valid OSR values, as listed in ad4030_average_modes[]. Validate avg_val fully before computing its log2, using is_power_of_2() and requiring avg_val > 0. This issue was identified with assistance from Claude AI and manually verified against the code. Fixes: 949abd1ca5a4 ("iio: adc: ad4030: add averaging support") Signed-off-by: Salah Triki --- Changes since v1: - Added note stating the issue was identified with assistance from Claude AI and verified manually. - Removed initialization of avg_log2 at declaration. drivers/iio/adc/ad4030.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/iio/adc/ad4030.c b/drivers/iio/adc/ad4030.c index 9c5f19321e3b..20911cc55873 100644 --- a/drivers/iio/adc/ad4030.c +++ b/drivers/iio/adc/ad4030.c @@ -746,14 +746,16 @@ static int ad4030_set_chan_calibbias(struct iio_dev *indio_dev, static int ad4030_set_avg_frame_len(struct iio_dev *dev, int avg_val) { struct ad4030_state *st = iio_priv(dev); - unsigned int avg_log2 = ilog2(avg_val); + unsigned int avg_log2; unsigned int last_avg_idx = ARRAY_SIZE(ad4030_average_modes) - 1; int freq_hz; int ret; - if (avg_val < 0 || avg_val > ad4030_average_modes[last_avg_idx]) + if (avg_val <= 0 || avg_val > ad4030_average_modes[last_avg_idx] || !is_power_of_2(avg_val)) return -EINVAL; + avg_log2 = ilog2(avg_val); + if (st->offload_trigger) { /* * The sample averaging and sampling frequency configurations -- 2.43.0