From nobody Mon Feb 9 15:09:32 2026 Received: from mail-yb1-f201.google.com (mail-yb1-f201.google.com [209.85.219.201]) (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 247E628FC for ; Wed, 3 Apr 2024 00:52:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712105559; cv=none; b=qxzrAJHqbAXkeb4zFmMeNtnQKBioiaq5g2LidE3Qjsed0rvnJrJ8M5JVgJgJrrwSSUbV5CnWEuCgACz05yLcgafHS9t5EVEHQzx40Xp1nwC4BGobb0d/lXcMQj4XrcsEiMmr7DGk2QG1LwWGu3yJOniqXJN7FEChJQdFUD1anHI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712105559; c=relaxed/simple; bh=AMBZZucRDLbkCBnpUsFkHT1Acvq2JW3K7G/CZEuEqfE=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=q/3e6D3ElwHFPbxkY9XcY47PhldbUwCIs1dx1Ixvja1LLP6Dys9cP1sHfjcCYq8GgcbMPX9GscpADM8EcUMRrdDQ9+zeEbl3+Eoi0Pu/N3aApUIdPyfp1r8yWSuAk/kWJ/21NmmPH3KNMDwvfUSd4Ds79QFzloNGp7G7K6DcvmY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--justinstitt.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=V1NdzGZW; arc=none smtp.client-ip=209.85.219.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--justinstitt.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="V1NdzGZW" Received: by mail-yb1-f201.google.com with SMTP id 3f1490d57ef6-dd8e82dd47eso7819366276.2 for ; Tue, 02 Apr 2024 17:52:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1712105557; x=1712710357; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=2LtWRlkSNk32zYyNyz1b834Pph06BPJDWHucHrmrXSY=; b=V1NdzGZWloPXuLxDqb/B8tmJQPVGQnQmw+bKqLVmL7rOtFACzymWsvAwnP7tIVfkLD s4IwLwXfAK8T4p3EeJCPxDJ8lNkAYVvcAFSmbpOh1vfeui2rZSMtQF0yIUPCBeJkmN7x SmxzA4mE6X/kCFH7OClcwbzIuAfY2agibcTt6Wzm2cDm+f63LoOxvrvKdVwK/5Ab7SmV PZPEvKWT68Vk0t+ruOoFQOO7nHvAIoh9W8gR3R3Pffy+aA4dii2G/YQCIFDfYU5MKRLN Y0SfQ0Sta0PmbjnNqcOF736arowuF99YZE5eF/+BWbVUWomluW9EcbPoBkNp56EfjclF kY7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1712105557; x=1712710357; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=2LtWRlkSNk32zYyNyz1b834Pph06BPJDWHucHrmrXSY=; b=JYH1aN77ttyK+S3UECfQxD7jeiIJBw2GQ6Gl3l1Ucr+hvs0cz13U6iakf+GKzxNIju TzrKboe7+rk59K2s+mjdfmfxihI+v+qA531TtMovgW1z7KluDmRMMgUjNwjmuSSnyFlZ Dc+sD0bZnvph8LwekaX5Oy9LqROKn4zIRLw3YwJMqZfrt13sYL2oR9dZVYWS+zVorVph 5dodhqc4EnRrioik6Aj4k0ePtSh2jYqSyX3kabpZ6J3bAniQdFwL5U6qeu/eiB0yOl2y 6pUASmhkXjEzHAz0E9jl+J5hbVOB+tp0lMDjQgNSjkt9mV+3wKDpm3CS9uxI4nNkJasg 1j/g== X-Forwarded-Encrypted: i=1; AJvYcCVPKAsl3QjTayxnTe8nfpvla5YnlHWQJX89Ypy1wRFzAuswZClpETDIXS2R6gjazju67nxLqlWbN0BNzRMFWHhvqoBmuVIdLTZQG2zb X-Gm-Message-State: AOJu0Yy9BnbqQEpV2RwNh7AK7gog8uZ619S+onf7QBB0ouqhbcfeP8Vm 4f193KedBsRVmra9kKh065b9EFNHn/2kqVq8h1Pl2HUdng13nfpZ5SpNQ8oulGvQepa0RaLFAyg jTtWFDDeOKRP/HYEckJVoPQ== X-Google-Smtp-Source: AGHT+IENHtMGTKiMA0s2/kOwugq4yr4dOndu0KnzLEY/2IVlh0JUmWjmdLHBkuswQWDSDEhDP1VdBsuAqxFROrPxgA== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a05:6902:1b09:b0:dc6:c94e:fb85 with SMTP id eh9-20020a0569021b0900b00dc6c94efb85mr980999ybb.2.1712105557231; Tue, 02 Apr 2024 17:52:37 -0700 (PDT) Date: Wed, 03 Apr 2024 00:52:36 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAFOoDGYC/x2NwQ6CMBAFf4Xs2U1qAQ/+CjEGuk/cQArZKoEQ/ p3qYQ5zmdkpwRSJ7sVOhkWTTjHL9VJQeLexB6tkJ+985SrnOX0shnnjARYxsqD79jxI9+OpEwe uS9QQf5O2FMqd2fDS9f9oHsdxAlV4hjpzAAAA X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1712105556; l=1581; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=AMBZZucRDLbkCBnpUsFkHT1Acvq2JW3K7G/CZEuEqfE=; b=5vCiLZjVHanyhM6gz89NkA5pyYDVG+O71KYpStpAjblh7KSvarGbuKYfVC5QMLNwXCs/IhIuP Rq24m4eV/t/B4SeYnsudISx/x6NQCQ+38VqG8fIE7d7TQ8vT8eU4wBo X-Mailer: b4 0.12.3 Message-ID: <20240403-strncpy-kernel-debug-kdb-kdb_io-c-v1-1-7f78a08e9ff4@google.com> Subject: [PATCH] kdb: replace deprecated strncpy From: Justin Stitt To: Jason Wessel , Daniel Thompson , Douglas Anderson Cc: kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable All the other cases in this big switch statement use memcpy or other methods for copying string data. Since the lengths are handled manually and carefully, using strncpy() is may be misleading. It doesn't guarantee any sort of NUL-termination on its destination buffer. At any rate, it's deprecated [1] and we want to remove all its uses [2]. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncp= y-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 [2] Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt --- Note: build-tested only. Found with: $ rg "strncpy\(" --- kernel/debug/kdb/kdb_io.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c index 9443bc63c5a2..8bba77b4a39c 100644 --- a/kernel/debug/kdb/kdb_io.c +++ b/kernel/debug/kdb/kdb_io.c @@ -368,9 +368,9 @@ static char *kdb_read(char *buffer, size_t bufsize) kdb_printf("%s", buffer); } else if (tab !=3D 2 && count > 0) { len_tmp =3D strlen(p_tmp); - strncpy(p_tmp+len_tmp, cp, lastchar-cp+1); + memcpy(p_tmp+len_tmp, cp, lastchar-cp+1); len_tmp =3D strlen(p_tmp); - strncpy(cp, p_tmp+len, len_tmp-len + 1); + memcpy(cp, p_tmp+len, len_tmp-len + 1); len =3D len_tmp - len; kdb_printf("%s", cp); cp +=3D len; --- base-commit: 026e680b0a08a62b1d948e5a8ca78700bfac0e6e change-id: 20240402-strncpy-kernel-debug-kdb-kdb_io-c-53e5ed26da3d Best regards, -- Justin Stitt