From nobody Mon Feb 9 12:33:47 2026 Received: from mail-m49197.qiye.163.com (mail-m49197.qiye.163.com [45.254.49.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EC5AC27CB2F; Fri, 11 Apr 2025 04:45:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.254.49.197 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744346709; cv=none; b=qW5kGFWhuAEXvrgelpMYNoCToswA2T1A/kLStu+gZE7As2KX8V77u0gseinU/JZMIus8FKQtzzyfwjEvXS+mow6qq9GEEi+39VSNHbj9uozWohdIKESlRW/SH0//olBe0zzQxTT2vOMWVET+sCJ5jpfB055j+QH7PUUF2/rO5LA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744346709; c=relaxed/simple; bh=DNTUCAbzivbGtmjnFnIu06G0T3ku4zWDyqLTUN10mns=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=d6Dvw/SJwTQ9Je7BGtXDvq4i0JSgBZUqPVjpKxOrdTQBGAbul3a/kDz+qveKcVoWHMjhudSj528JV28JWuZ0/+D8GrZt/Xwlrwu1DS9f9JRKo/C3B4/EKmmY+jt+afgllD8wsM0fLpOvv+44dCI0H1bslgvTtTCm7qStTf2cmfY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=seu.edu.cn; spf=pass smtp.mailfrom=seu.edu.cn; dkim=pass (1024-bit key) header.d=seu.edu.cn header.i=@seu.edu.cn header.b=W+XewHD5; arc=none smtp.client-ip=45.254.49.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=seu.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=seu.edu.cn Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=seu.edu.cn header.i=@seu.edu.cn header.b="W+XewHD5" Received: from localhost.localdomain (unknown [202.119.23.198]) by smtp.qiye.163.com (Hmail) with ESMTP id 117c6ece2; Fri, 11 Apr 2025 12:44:59 +0800 (GMT+08:00) From: Zilin Guan To: wenjia@linux.ibm.com Cc: jaka@linux.ibm.com, alibuda@linux.alibaba.com, tonylu@linux.alibaba.com, guwen@linux.alibaba.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, linux-rdma@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, jianhao.xu@seu.edu.cn, Zilin Guan Subject: [RFC PATCH] net/smc: Consider using kfree_sensitive() to free cpu_addr Date: Fri, 11 Apr 2025 04:44:56 +0000 Message-Id: <20250411044456.1661380-1-zilin@seu.edu.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-HM-Spam-Status: e1kfGhgUHx5ZQUpXWQgPGg8OCBgUHx5ZQUlOS1dZFg8aDwILHllBWSg2Ly tZV1koWUFITzdXWS1ZQUlXWQ8JGhUIEh9ZQVlCTEhCVkJIGh0aQkkZSUIeTlYeHw5VEwETFhoSFy QUDg9ZV1kYEgtZQVlJS0lVSkpCVUlIVUpCQ1lXWRYaDxIVHRRZQVlPS0hVSktISk9ITFVKS0tVSk JLS1kG X-HM-Tid: 0a96232a562603a1kunm117c6ece2 X-HM-MType: 10 X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Pxg6Izo*NDJKLDUcMSkcEhoz FUIKCitVSlVKTE9PSE9NTEtLTUhOVTMWGhIXVQESFxIVOwgeDlUeHw5VGBVFWVdZEgtZQVlJS0lV SkpCVUlIVUpCQ1lXWQgBWUFJSE5DNwY+ DKIM-Signature: a=rsa-sha256; b=W+XewHD5T/DrVlYlf70G4CwonfJrv16/xwTI5F6FKPD1zcqZYxYBc2SH6Xf5Hsig9SYBXgEZa5tzTSoqb3EqTtzLXfZ+ATofbKKL1zlwHkZfxh4dqygk2yG+3xBRcDdD1zNxg1Up+ajZQO8HuWC7Yq6lmw3Ut42V0pCpKglAFVU=; s=default; c=relaxed/relaxed; d=seu.edu.cn; v=1; bh=PL2S5ZNY/lfRwbYp6izyK3pe6SK3sLEiQc6v851Wktc=; h=date:mime-version:subject:message-id:from; Content-Type: text/plain; charset="utf-8" Hello, In smcr_buf_unuse() and smc_buf_unuse(), memzero_explicit() is used to clear cpu_addr when it is no longer in use, suggesting that cpu_addr may contain sensitive information. To ensure proper handling of this sensitive memory, I propose using kfree_sensitive()/kvfree_sensitive instead of kfree()/vfree() to free cpu_addr in both smcd_buf_free() and smc_buf_free(). This change aims to prevent potential sensitive data leaks. I am submitting this as an RFC to seek feedback on whether this change is appropriate and aligns with the subsystem's expectations. If confirmed to be useful, I will send a formal patch. Signed-off-by: Zilin Guan --- net/smc/smc_core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index ac07b963aede..1b5eb0149b89 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1388,7 +1388,7 @@ static void smcr_buf_free(struct smc_link_group *lgr,= bool is_rmb, if (!buf_desc->is_vm && buf_desc->pages) __free_pages(buf_desc->pages, buf_desc->order); else if (buf_desc->is_vm && buf_desc->cpu_addr) - vfree(buf_desc->cpu_addr); + kvfree_sensitive(buf_desc->cpu_addr, buf_desc->len); kfree(buf_desc); } =20 @@ -1400,7 +1400,7 @@ static void smcd_buf_free(struct smc_link_group *lgr,= bool is_dmb, buf_desc->len +=3D sizeof(struct smcd_cdc_msg); smc_ism_unregister_dmb(lgr->smcd, buf_desc); } else { - kfree(buf_desc->cpu_addr); + kfree_sensitive(buf_desc->cpu_addr); } kfree(buf_desc); } --=20 2.34.1