From: Adrian Reber <areber@redhat.com>
To: "Christian Brauner" <christian.brauner@ubuntu.com>,
"Eric Biederman" <ebiederm@xmission.com>,
"Pavel Emelyanov" <ovzxemul@gmail.com>,
"Oleg Nesterov" <oleg@redhat.com>,
"Dmitry Safonov" <0x7f454c46@gmail.com>,
"Andrei Vagin" <avagin@gmail.com>,
"Nicolas Viennot" <Nicolas.Viennot@twosigma.com>,
"Michał Cłapiński" <mclapinski@google.com>,
"Kamil Yurtsever" <kyurtsever@google.com>,
"Dirk Petersen" <dipeit@gmail.com>,
"Christine Flood" <chf@redhat.com>,
"Casey Schaufler" <casey@schaufler-ca.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>,
Radostin Stoyanov <rstoyanov1@gmail.com>,
Adrian Reber <areber@redhat.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Serge Hallyn <serge@hallyn.com>,
Stephen Smalley <stephen.smalley.work@gmail.com>,
Sargun Dhillon <sargun@sargun.me>, Arnd Bergmann <arnd@arndb.de>,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, selinux@vger.kernel.org,
Eric Paris <eparis@parisplace.org>, Jann Horn <jannh@google.com>,
linux-fsdevel@vger.kernel.org
Subject: [PATCH v6 4/7] proc: allow access in init userns for map_files with CAP_CHECKPOINT_RESTORE
Date: Sun, 19 Jul 2020 12:04:14 +0200 [thread overview]
Message-ID: <20200719100418.2112740-5-areber@redhat.com> (raw)
In-Reply-To: <20200719100418.2112740-1-areber@redhat.com>
Opening files in /proc/pid/map_files when the current user is
CAP_CHECKPOINT_RESTORE capable in the root namespace is useful for
checkpointing and restoring to recover files that are unreachable via
the file system such as deleted files, or memfd files.
Signed-off-by: Adrian Reber <areber@redhat.com>
Signed-off-by: Nicolas Viennot <Nicolas.Viennot@twosigma.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
fs/proc/base.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 65893686d1f1..b824a8c89011 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2194,16 +2194,16 @@ struct map_files_info {
};
/*
- * Only allow CAP_SYS_ADMIN to follow the links, due to concerns about how the
- * symlinks may be used to bypass permissions on ancestor directories in the
- * path to the file in question.
+ * Only allow CAP_SYS_ADMIN and CAP_CHECKPOINT_RESTORE to follow the links, due
+ * to concerns about how the symlinks may be used to bypass permissions on
+ * ancestor directories in the path to the file in question.
*/
static const char *
proc_map_files_get_link(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
- if (!capable(CAP_SYS_ADMIN))
+ if (!checkpoint_restore_ns_capable(&init_user_ns))
return ERR_PTR(-EPERM);
return proc_pid_get_link(dentry, inode, done);
--
2.26.2
next prev parent reply other threads:[~2020-07-19 10:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-19 10:04 [PATCH v6 0/7] capabilities: Introduce CAP_CHECKPOINT_RESTORE Adrian Reber
2020-07-19 10:04 ` [PATCH v6 1/7] " Adrian Reber
2020-07-19 10:04 ` [PATCH v6 2/7] pid: use checkpoint_restore_ns_capable() for set_tid Adrian Reber
2020-07-19 10:04 ` [PATCH v6 3/7] pid_namespace: use checkpoint_restore_ns_capable() for ns_last_pid Adrian Reber
2020-07-19 10:04 ` Adrian Reber [this message]
2020-07-19 16:50 ` [PATCH v6 4/7] proc: allow access in init userns for map_files with CAP_CHECKPOINT_RESTORE Serge E. Hallyn
2020-07-19 10:04 ` [PATCH v6 5/7] prctl: Allow local CAP_CHECKPOINT_RESTORE to change /proc/self/exe Adrian Reber
2020-07-19 10:04 ` [PATCH v6 6/7] prctl: exe link permission error changed from -EINVAL to -EPERM Adrian Reber
2020-07-19 17:05 ` Serge E. Hallyn
2020-07-19 10:04 ` [PATCH v6 7/7] selftests: add clone3() CAP_CHECKPOINT_RESTORE test Adrian Reber
2020-07-19 18:17 ` [PATCH v6 0/7] capabilities: Introduce CAP_CHECKPOINT_RESTORE Christian Brauner
2020-07-20 11:54 ` Christian Brauner
2020-07-20 12:46 ` Adrian Reber
2020-07-20 12:58 ` Christian Brauner
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