From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (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 C73232C11E6 for ; Wed, 7 Oct 2026 19:48:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791402519; cv=none; b=Efcq7WVLRMWJInK1Xdwxnrz9Rr2mNNc3WyJacJrTbe784m5tIviBk/x3O/uuoqouetKBojoEU2sO5bVgzdTVVv3YNEJBDniRggBASMfsfFFp7xcYtG4tBduB/RksdguTjIT1fQODhj6cpBb1F+dofOFeQnPGXcrebl0ON9Si49I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791402519; c=relaxed/simple; bh=O5vrvk62RFNzvWg39pokce9j52N15tZ95rRkY8miVfo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=lRhurEbekpbAbVcnvK+o47yGqTTKQZGTt8i3Wi1wxR2I3hSY3ZZD2vrc7GaTm00RDLs4riJmf0OFdm/WYIbbLIqssW++yPZiMgnnpWcQkHYdbRtrgvUkm4y0zUNsck66maGPp4TTLVslSXgD8UuVhtmJuhYPdQN1QbrOp/ZdO0k= 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=cFG49HVi; arc=none smtp.client-ip=209.85.214.172 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="cFG49HVi" Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-2db710396ffso13172455ad.1 for ; Wed, 07 Oct 2026 12:48:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1791402518; x=1792007318; 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=pbKYcyGwwt5OH5lSkH465y98UeyGwofmWr2r/6Q02/Q=; b=cFG49HViZAjq5+czgH+i8zMO6OeYFtlvLPr1TC60B6Rz3s36lxsVlsk2cKMCKfhkcG as84+bWtG8rUT7ef8X5+ZCEKJclhBp7dqXGY5aOPTqO3hBJSuxDohUzA2wZ9TW+9fBJn jMDVT4d8UvFpdaI8fmN64yw5Jf2VIaQIRZkzNJsk1XmCD0Vvsh16WSdFZQNqikHwFfA+ X5yPk/+giA2hpw6uGIGLmAzcWVuHxlkePSQkn6PFfF37Ds9rXltXwcosQZa9Wqg2z8ep /1EUrR+ijVp2VNEJAduew8W3cS9vhqud18zT0TNChbzFOk/myv7l++uZhxxbEW7pOUmE UT8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791402518; x=1792007318; 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=pbKYcyGwwt5OH5lSkH465y98UeyGwofmWr2r/6Q02/Q=; b=2FUwoKnYdn4kQjL6as61yOvAO8PPx9UgxcntYNA76ViZyyTe+DYwAFHnQ3ognTrYUb 90KHAZkfaxH2JukJ7qRpGjifR8uPrnjngAQywC4VNFGGVVgHFMhDabl2uLb+/U+mRLG6 AbCloknP/MP2zumxoJoDzSkc6qeF6JFNSRmFGuBrDeDPANvueO7HqrIRVLkPA3degobs kM6QaRlhoqyLVHRtzSU4WPxs/A/hT3Lu/ZfeJwPGE+F/oGWVsTOhO7R9m/V/6xX5Uwk9 C9y0a0K37Pu9H1z5eLTVP0B2vrmiicTLoPEpWioWlNcVCq4j8lc5dVjfCm6sOZ2I29VO gB1w== X-Gm-Message-State: AFq9FYJK9zrg/fCYWo0DQ1V8TzlZoSysK6wKABJd/446VmpzOg8NF//1 hppeh7fRTAAJ0z1VrS3UmyLxJyVe1M4Q8gJtg0UHTrSBBCRJ8fYxUxCwzdUrRB++ X-Gm-Gg: AYBFou1nd/NhXLm4KaNpwf13zMAEaMp7247oFGv6IfOfvuExEvbx5IdY5/SvzAg7xss zbcj4mCZR0GKjpBcW/7Hb2j17AYp+J+DYrD3ioW0nGB/ITDcgLEpe1hB/WxRtPxiOBKMVrxnj6/ YZk+kky0pAC1wKs0ajJQU3BqYD7jBFiN/iVatShWROP7Bm99GnuQixAcK8bxw9AO+uFECYHwraT fdRny1ipu86h9kDa/alfq9ns/rwMm3u3BUr03hRFCyqWZZm5v65QwljsFmzPMYjOXUfgKpNXR8Y fBGVw7KIJcu1apJstNTbWUM2QZwWDgWPUKIzZMUB3CvBb8U7F2AoVZw6mHqzeDlqSoIiZqXy7UJ 1ZLSGdr19OxPrEs8/jVKFTHC58aRUnECgaUGUuSSwxP68KQAIrLmmvxGoOPl/o29pn+DXSJxs9u qNAVufqdBGuvrBPPClQJxx5hvBiLPDO69XrQ3wFpIr51U2acqiEf99L8VZmXT1tLTPC3hZ9ucCh qAl9VGrcPHDWysmOo0/4r+GKzxulukfytnxpVI3vGEN2mKsKmwHzK7MsxIalHcE8Dhgv0Y9dOxX Jh7GEHY/og== X-Received: by 2002:a17:903:46cf:b0:2e2:dc3f:4131 with SMTP id d9443c01a7336-2e7ffdc5fcemr1118475ad.14.1791402517656; Wed, 07 Oct 2026 12:48:37 -0700 (PDT) Received: from phui-2.c.googlers.com.com (25.187.82.34.bc.googleusercontent.com. [34.82.187.25]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2e6049497fcsm16696675ad.64.2026.10.07.12.48.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Oct 2026 12:48:37 -0700 (PDT) From: Hui Peng To: Marcel Holtmann , Johan Hovold , Luiz Augusto von Dentz Cc: linux-bluetooth@vger.kernel.org, Hui Peng Subject: [PATCH] sdp: Prevent integer underflow in string attribute length calculation Date: Wed, 7 Oct 2026 19:48:31 +0000 Message-ID: <20261007194831.2275879-1-benquike@gmail.com> X-Mailer: git-send-email 2.56.0.360.g66cac248cb-goog Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In lib/bluetooth/sdp.c, attribute string length calculations subtract sizeof(uint8_t) from d->unitSize (e.g. d->unitSize - sizeof(uint8_t)). When d->unitSize is 0 or less than sizeof(uint8_t), this subtraction underflows in 32-bit integer arithmetic to a negative/huge length value, passing invalid sizes to memory allocation and length extraction functions. Add explicit lower-bound guards to ensure that when d->unitSize <= sizeof(uint8_t), the calculated string length is safely set to 0. Assisted-by: Antigravity --- lib/bluetooth/sdp.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/lib/bluetooth/sdp.c b/lib/bluetooth/sdp.c index 1e027f9..a750274 100644 --- a/lib/bluetooth/sdp.c +++ b/lib/bluetooth/sdp.c @@ -730,7 +730,10 @@ static int sdp_get_data_size(sdp_buf_t *buf, sdp_data_t *d) case SDP_URL_STR8: case SDP_URL_STR16: case SDP_URL_STR32: - data_size = d->unitSize - sizeof(uint8_t); + if (d->unitSize > sizeof(uint8_t)) + data_size = d->unitSize - sizeof(uint8_t); + else + data_size = 0; break; case SDP_SEQ8: case SDP_SEQ16: @@ -1524,7 +1527,8 @@ static void *sdp_data_value(sdp_data_t *data, uint32_t *len) case SDP_TEXT_STR32: val = data->val.str; if (len) - *len = data->unitSize - sizeof(uint8_t); + *len = (data->unitSize > sizeof(uint8_t)) ? + (data->unitSize - sizeof(uint8_t)) : 0; break; case SDP_ALT8: case SDP_ALT16: @@ -4852,7 +4856,8 @@ int sdp_set_supp_feat(sdp_record_t *rec, const sdp_list_t *sf) case SDP_TEXT_STR8: case SDP_TEXT_STR16: vals[j] = data->val.str; - lengths[j] = data->unitSize - sizeof(uint8_t); + lengths[j] = (data->unitSize > sizeof(uint8_t)) ? + (data->unitSize - sizeof(uint8_t)) : 0; break; case SDP_ALT8: case SDP_ALT16: @@ -4929,7 +4934,8 @@ int sdp_get_supp_feat(const sdp_record_t *rec, sdp_list_t **seqp) case SDP_TEXT_STR8: case SDP_TEXT_STR16: val = dd->val.str; - length = dd->unitSize - sizeof(uint8_t); + length = (dd->unitSize > sizeof(uint8_t)) ? + (dd->unitSize - sizeof(uint8_t)) : 0; break; case SDP_UINT8: case SDP_UINT16: -- 2.47.3