From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f182.google.com (mail-pl1-f182.google.com [209.85.214.182]) (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 591903271F0 for ; Thu, 19 Feb 2026 14:27:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771511240; cv=none; b=rwRZH9pH0vSiRAfqu7D7Lo3Yau6ejYRg9P0hg6SECNAth14Nc7wqatmnblp+NYmdh8f5R9/aWfkmfiuZac4AP4P1yqBUCVdTF/03E1GiV4h/SVlVP/ZYj35UCmreHBs206fF46u0S2cftmfd9lMmg3clqPcS1s1xeAoUKBS8Y2g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771511240; c=relaxed/simple; bh=fFFjkseekXvGYoGHHkDvbbj+CFQfCypI5+YXQEHeZys=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Jas4zSZsR2SmP8A4ZRwNKVYf+gaW6yKh0wjMsVdt6oniXQkZ0n4g4N3TaGanWUv5YEuije4hvQUwAA82QTCYvEcDsbRekUkYjcgsfrfOA/qTlcgB2deT+p8m784w0DGmUmtqyaCcWacm4kgvMYsxUMAarwuK3k5kL4+RWBhnUG0= 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=mTKJYUCu; arc=none smtp.client-ip=209.85.214.182 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="mTKJYUCu" Received: by mail-pl1-f182.google.com with SMTP id d9443c01a7336-2aae146b604so6679385ad.3 for ; Thu, 19 Feb 2026 06:27:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1771511239; x=1772116039; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=QUt8gjFDI6W7zJiz3u2Nn1UdNatjAJ3oKKX8MoonuYU=; b=mTKJYUCugpcn5L5mDXdK+YRi2UNxKjfLhPZDzkq9uL2gWuXt5GfBk+YRqBoCvSizv7 T0ZzF0FqkaNIbu43klTvaVMV32XKzclXitql0gtOptcBXs7XggysZRWE62OR1VtS9c+D xsKr/L+2M9oz/lxvYf6HHScQb9piufGqG8lHKyHiyVzFJXoCb8+WB7WY5fLWtR6pwE3G feGKgcVqrcwm7tL7NSSjf8r7myNfNU8hsp3WIwSWe2h0GfZ8PuHW9Fy3rs9A/DrYYEUs fY3UwTUZzkJLE4GUZFgbWwlF3dYd1dEsKPy2DoyMUan8pYYIKR9r1uE0ARa/zVxECMyv +SjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771511239; x=1772116039; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=QUt8gjFDI6W7zJiz3u2Nn1UdNatjAJ3oKKX8MoonuYU=; b=FzudI18Pb7OIHJDcw93rxbgRMgTCxuqY4sHS1Xz1gi4GDDOtKgGnsNFgVc1EWP4NoE hK13u0yN7Y8z4xTkwAP8OjNvV46uz51MpT3duBohxocEAY0UhuCKPjXYhshduNuBWGWN WETws5rG/RUJ825ciPuccY1fbPec6FPNhCWqKwz0xCkB2ZZCpfLb3nT+K6w0OQEiaJQd 3oft8Bc5KZYqkB4Imup1dyfbrZg77l7Lk61Hvc00srzPZLDJfkIGrUXkrKSfliiLWj6T /HrY3zMWjMFR1THJijYkMvtbQeOXvNMUb/U/UUb7dQGfcgs1idCPAl9rrXgMs7vbnOGU oGkA== X-Forwarded-Encrypted: i=1; AJvYcCUVgEWMW9Nw294MpZNquFSGwOlaud5xHhMEJhn30LxYpDkuNU+x8Um5YE5jGOzmWUkUV3k4i4mJcMSkyk7oCHbN/XMf4sA=@vger.kernel.org X-Gm-Message-State: AOJu0YzCbIQoYKVvOdaQdJmi0ghDLL/N1DDE+dYtFwnI/62nHc4+JSTm fabZszRZdlKzjP4x5wq8+94drht07dgog3/UUwYjj7soZz7ReG3tP8a+ X-Gm-Gg: AZuq6aL/DGO8XtZU3h//lpUL/19nCdjUV7C7q8G4oO3sGUD3FxH4uPTNbnIwxWo1799 6nuWyvRxZW0DDUGWtX9xD1wYQTtUhe3efDnUlug+q0qBPTngktaVwud+YEbNBNQB/jLbJwo9TZj FESwI+CdohPh7RfffvgJI91lS1/YE2J6a938NaUKuvbBzsW4zVlS7a9qC0oWxyaW3osbkEOZxKB KcKGjZ/hfrodkZccpeuABqAGQk+YrOqEqtvAzpEuDqpq4BTmYpt8MNnG+6wEvfBytjre22J1MXe 7TImycgvBTahu++Ck5aMvngK5NXk5iFYXNDVANwOh1P1T8Zzt1Hgdz5NUzq2V41nqosdUvU7PQy CJMW+O2PE2fsERvlNQ7Elh+SpJsCFdwYF382Xdl8r54hvhIkkP2wfXFs5DIFJqj6PNr6RqDhnNL c6Q7azi7wmou3XBXcH8qi3NbCDgOlNzXpvkAa6hEnYzSgfWmjE5bn/aAEB0txmTnAt X-Received: by 2002:a17:903:388c:b0:2a0:d636:71e7 with SMTP id d9443c01a7336-2ab4cf7c628mr180445875ad.13.1771511238647; Thu, 19 Feb 2026 06:27:18 -0800 (PST) Received: from ?IPV6:240e:38a:19d2:ad01:4c90:983:b066:e0db? ([240e:38a:19d2:ad01:4c90:983:b066:e0db]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ad1a9d5c4csm166275275ad.53.2026.02.19.06.27.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 19 Feb 2026 06:27:18 -0800 (PST) Message-ID: Date: Thu, 19 Feb 2026 22:27:01 +0800 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] task: delete task_euid() To: Alice Ryhl , Paul Moore , Serge Hallyn , Jonathan Corbet , Greg Kroah-Hartman , Shuah Khan , Alex Shi , Yanteng Si , Dongliang Mu Cc: Miguel Ojeda , Boqun Feng , Gary Guo , =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Trevor Gross , Danilo Krummrich , linux-security-module@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Jann Horn References: <20260219-remove-task-euid-v1-1-904060826e07@google.com> Content-Language: en-US From: Alex Shi In-Reply-To: <20260219-remove-task-euid-v1-1-904060826e07@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2026/2/19 20:14, Alice Ryhl wrote: > task_euid() is a very weird operation. You can see how weird it is by > grepping for task_euid() - binder is its only user. task_euid() obtains > the objective effective UID - it looks at the credentials of the task > for purposes of acting on it as an object, but then accesses the > effective UID (which the credentials.7 man page describes as "[...] used > by the kernel to determine the permissions that the process will have > when accessing shared resources [...]"). > > Since usage in Binder has now been removed, get rid of the resulting > dead code. > > Changes to the zh_CN translation was carried out with the help of > Gemini and Google Translate. > > Suggested-by: Jann Horn > Signed-off-by: Alice Ryhl > --- > Depends on these two changes: > https://lore.kernel.org/all/20260212-rust-uid-v1-1-deff4214c766@google.com/ > https://lore.kernel.org/all/20260213-binder-uid- > v1-0-7b795ae05523@google.com/ > --- > Documentation/security/credentials.rst | 6 ++---- > Documentation/translations/zh_CN/security/credentials.rst | 6 ++---- > include/linux/cred.h | 1 - > rust/helpers/task.c | 5 ----- > rust/kernel/task.rs | 10 ---------- > 5 files changed, 4 insertions(+), 24 deletions(-) > > diff --git a/Documentation/security/credentials.rst b/Documentation/security/credentials.rst > index d0191c8b8060edb7b272402c019cff941ec22743..81d3b5737d85bde9b77bff94dfb93ed8037b2302 100644 > --- a/Documentation/security/credentials.rst > +++ b/Documentation/security/credentials.rst > @@ -393,16 +393,14 @@ the credentials so obtained when they're finished with. > The result of ``__task_cred()`` should not be passed directly to > ``get_cred()`` as this may race with ``commit_cred()``. > > -There are a couple of convenience functions to access bits of another task's > -credentials, hiding the RCU magic from the caller:: > +There is a convenience function to access bits of another task's credentials, > +hiding the RCU magic from the caller:: > > uid_t task_uid(task) Task's real UID > - uid_t task_euid(task) Task's effective UID > > If the caller is holding the RCU read lock at the time anyway, then:: > > __task_cred(task)->uid > - __task_cred(task)->euid > > should be used instead. Similarly, if multiple aspects of a task's credentials > need to be accessed, RCU read lock should be used, ``__task_cred()`` called, > diff --git a/Documentation/translations/zh_CN/security/credentials.rst b/Documentation/translations/zh_CN/security/credentials.rst > index 88fcd9152ffe91d79fc10bfc7b2a37d301b4938a..f0b2efec342438b81be415dc513622c961bb7e59 100644 > --- a/Documentation/translations/zh_CN/security/credentials.rst > +++ b/Documentation/translations/zh_CN/security/credentials.rst > @@ -337,15 +337,13 @@ const指针上操作，因此不需要进行类型转换，但需要临时放弃 > ``__task_cred()`` 的结果不应直接传递给 ``get_cred()`` ， > 因为这可能与 ``commit_cred()`` 发生竞争条件。 > > -还有一些方便的函数可以访问另一个任务凭据的特定部分，将RCU操作对调用方隐藏起来:: > +有一个方便的函数可用于访问另一个任务凭据的特定部分，从而对调用方隐藏RCU机制:: LGTM. > > uid_t task_uid(task) Task's real UID > - uid_t task_euid(task) Task's effective UID > > -如果调用方在此时已经持有RCU读锁，则应使用:: > +如果调用方在此时已经持有RCU读锁，则应改为使用:: Please keep the old version. the new one is a bit ambiguous. Thanks Alex