From: "Dmitry V. Levin" <ldv@altlinux.org>
To: devel@lists.altlinux.org
Subject: Re: [devel] I: brp-verify-unit: "... assumes overflowugid credentials"
Date: Mon, 12 Feb 2024 12:34:06 +0200
Message-ID: <20240212103406.GB1493@altlinux.org> (raw)
In-Reply-To: <067bf2a1-7222-4959-827d-541d12a2a1fe@basealt.ru>
On Mon, Feb 12, 2024 at 08:58:30AM +0300, Anton Farygin wrote:
> On 12.02.2024 01:12, Dmitry V. Levin wrote:
> > Кто-нибудь может мне рассказать, почему ядро до сих пор ещё разрешает
> > setuid(overflowuid)? Это же по сути отменяет саму идею, заложенную
> > в overflowuid.
> >
> Сейчас при входе в систему доменным пользователем UID получается 32-х
> битный.
>
> overflow оно только на старых системах, где UID/GID 16-бит.
Всё обстоит несколько иначе. Не готов читать лекцию, желающие могут
обратиться к первоисточнику самостоятельно:
linux$ git grep overflowuid
Documentation/admin-guide/sysctl/fs.rst:overflowgid & overflowuid
Documentation/admin-guide/sysctl/kernel.rst:overflowgid & overflowuid
Documentation/filesystems/idmappings.rst:third idmapping. The kernel will report unmapped ids as the overflowuid
drivers/gpu/drm/drm_ioctl.c: client->uid = overflowuid;
fs/sysctls.c: .procname = "overflowuid",
fs/sysctls.c: .data = &fs_overflowuid,
fs/udf/super.c: uopt.uid = make_kuid(current_user_ns(), overflowuid);
include/linux/highuid.h:extern int overflowuid;
include/linux/highuid.h:#define high2lowuid(uid) ((uid) & ~0xFFFF ? (old_uid_t)overflowuid : (old_uid_t)(uid))
include/linux/highuid.h:extern int fs_overflowuid;
include/linux/highuid.h:#define fs_high2lowuid(uid) ((uid) & ~0xFFFF ? (uid16_t)fs_overflowuid : (uid16_t)(uid))
include/linux/uidgid.h: uid = overflowuid;
include/uapi/linux/bpf.h: * time-wait or a request socket instead), **overflowuid** value
include/uapi/linux/bpf.h: * is returned (note that **overflowuid** might also be the actual
kernel/sys.c:int overflowuid = DEFAULT_OVERFLOWUID;
kernel/sys.c:EXPORT_SYMBOL(overflowuid);
kernel/sys.c:int fs_overflowuid = DEFAULT_FS_OVERFLOWUID;
kernel/sys.c:EXPORT_SYMBOL(fs_overflowuid);
kernel/sysctl.c: .procname = "overflowuid",
kernel/sysctl.c: .data = &overflowuid,
kernel/user_namespace.c: * If @kuid has no mapping in @targ overflowuid is returned.
kernel/user_namespace.c: uid = overflowuid;
net/core/filter.c: return overflowuid;
--
ldv
next prev parent reply other threads:[~2024-02-12 10:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-10 11:37 Arseny Maslennikov
2024-02-10 14:06 ` Anton Farygin
2024-02-10 15:23 ` Arseny Maslennikov
2024-02-11 22:12 ` Dmitry V. Levin
2024-02-12 5:58 ` Anton Farygin
2024-02-12 10:34 ` Dmitry V. Levin [this message]
2024-02-12 10:50 ` Anton Farygin
2024-02-12 13:16 ` Arseny Maslennikov
2024-02-12 5:44 ` Anton Farygin
2024-02-12 7:45 ` [devel] I: brp-verify-unit: "... assumes overflowugid Alexey V. Vissarionov
2024-02-12 7:52 ` Anton Farygin
2024-02-12 8:04 ` Alexey V. Vissarionov
2024-02-12 14:23 ` [devel] I: brp-verify-unit: "... assumes overflowugid credentials" Arseny Maslennikov
2024-02-12 14:33 ` Arseny Maslennikov
2024-02-12 14:48 ` Anton Farygin
2024-02-18 13:35 ` Vitaly Lipatov
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