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From: Christian Brauner <christian.brauner@ubuntu.com>
To: "Stéphane Graber" <stgraber@ubuntu.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Aleksa Sarai" <cyphar@cyphar.com>,
	"Jann Horn" <jannh@google.com>
Cc: smbarber@chromium.org, Seth Forshee <seth.forshee@canonical.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Serge Hallyn <serge@hallyn.com>, James Morris <jmorris@namei.org>,
	Kees Cook <keescook@chromium.org>,
	Jonathan Corbet <corbet@lwn.net>, Phil Estes <estesp@gmail.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	containers@lists.linux-foundation.org,
	linux-security-module@vger.kernel.org, linux-api@vger.kernel.org,
	Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH v2 18/28] capability: privileged_wrt_inode_uidgid(): handle fsid mappings
Date: Fri, 14 Feb 2020 19:35:44 +0100
Message-ID: <20200214183554.1133805-19-christian.brauner@ubuntu.com> (raw)
In-Reply-To: <20200214183554.1133805-1-christian.brauner@ubuntu.com>

Switch privileged_wrt_inode_uidgid() to lookup fsids in the fsid mappings. If
no fsid mappings are setup the behavior is unchanged, i.e. fsids are looked up
in the id mappings.

Filesystems that share a superblock in all user namespaces they are mounted in
will retain their old semantics even with the introduction of fsidmappings.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
/* v2 */
unchanged
---
 kernel/capability.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/kernel/capability.c b/kernel/capability.c
index 1444f3954d75..2b0c1dc992e2 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -19,6 +19,8 @@
 #include <linux/pid_namespace.h>
 #include <linux/user_namespace.h>
 #include <linux/uaccess.h>
+#include <linux/fsuidgid.h>
+#include <linux/fs.h>
 
 /*
  * Leveraged for setting/resetting capabilities
@@ -486,8 +488,12 @@ EXPORT_SYMBOL(file_ns_capable);
  */
 bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode)
 {
-	return kuid_has_mapping(ns, inode->i_uid) &&
-		kgid_has_mapping(ns, inode->i_gid);
+	if (is_userns_visible(inode->i_sb->s_iflags))
+		return kuid_has_mapping(ns, inode->i_uid) &&
+		       kgid_has_mapping(ns, inode->i_gid);
+
+	return kfsuid_has_mapping(ns, inode->i_uid) &&
+	       kfsgid_has_mapping(ns, inode->i_gid);
 }
 
 /**
-- 
2.25.0


  parent reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14 18:35 [PATCH v2 00/28] user_namespace: introduce " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 01/28] user_namespace: introduce fsid mappings infrastructure Christian Brauner
2020-02-14 18:35 ` [PATCH v2 02/28] proc: add /proc/<pid>/fsuid_map Christian Brauner
2020-02-14 18:35 ` [PATCH v2 03/28] proc: add /proc/<pid>/fsgid_map Christian Brauner
2020-02-14 18:35 ` [PATCH v2 04/28] fsuidgid: add fsid mapping helpers Christian Brauner
2020-02-14 19:11   ` Jann Horn
2020-02-16 16:55     ` Christian Brauner
2020-02-14 18:35 ` [PATCH v2 05/28] proc: task_state(): use from_kfs{g,u}id_munged Christian Brauner
2020-02-14 18:35 ` [PATCH v2 06/28] cred: add kfs{g,u}id Christian Brauner
2020-02-14 18:35 ` [PATCH v2 07/28] sys: __sys_setfsuid(): handle fsid mappings Christian Brauner
2020-02-14 18:35 ` [PATCH v2 08/28] sys: __sys_setfsgid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 09/28] sys:__sys_setuid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 10/28] sys:__sys_setgid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 11/28] sys:__sys_setreuid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 12/28] sys:__sys_setregid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 13/28] sys:__sys_setresuid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 14/28] sys:__sys_setresgid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 15/28] fs: add is_userns_visible() helper Christian Brauner
2020-02-14 18:35 ` [PATCH v2 16/28] namei: may_{o_}create(): handle fsid mappings Christian Brauner
2020-02-14 18:35 ` [PATCH v2 17/28] inode: inode_owner_or_capable(): " Christian Brauner
2020-02-14 18:35 ` Christian Brauner [this message]
2020-02-14 18:35 ` [PATCH v2 19/28] stat: " Christian Brauner
2020-02-14 19:03   ` Tycho Andersen
2020-02-16 14:12     ` Christian Brauner
2020-02-14 18:35 ` [PATCH v2 20/28] open: " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 21/28] posix_acl: " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 22/28] attr: notify_change(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 23/28] commoncap: cap_bprm_set_creds(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 24/28] commoncap: cap_task_fix_setuid(): " Christian Brauner
2020-02-14 18:35 ` [PATCH v2 25/28] commoncap: handle fsid mappings with vfs caps Christian Brauner
2020-02-14 18:35 ` [PATCH v2 26/28] exec: bprm_fill_uid(): handle fsid mappings Christian Brauner
2020-02-14 18:35 ` [PATCH v2 27/28] ptrace: adapt ptrace_may_access() to always uses unmapped fsids Christian Brauner
2020-02-14 18:35 ` [PATCH v2 28/28] devpts: handle fsid mappings Christian Brauner
2020-02-16 15:55 ` [PATCH v2 00/28] user_namespace: introduce " Florian Weimer
2020-02-16 16:40   ` Christian Brauner
2020-02-17 21:06 ` James Bottomley
2020-02-17 21:20   ` Christian Brauner
2020-02-17 22:35     ` James Bottomley
2020-02-17 23:05       ` Christian Brauner
2020-02-17 21:11 ` James Bottomley
     [not found]   ` <CA+enf=vwd-dxzve87t7Mw1Z35RZqdLzVaKq=fZ4EGOpnES0f5w@mail.gmail.com>
2020-02-17 22:02     ` Stéphane Graber
2020-02-17 23:03     ` James Bottomley
2020-02-17 23:11       ` Stéphane Graber

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