From: Paul Moore <[email protected]>
To: [email protected], [email protected],
[email protected], [email protected],
[email protected],
Kumar Kartikeya Dwivedi <[email protected]>,
Jens Axboe <[email protected]>,
Alexander Viro <[email protected]>
Subject: [RFC PATCH 8/9] selinux: add support for the io_uring access controls
Date: Fri, 21 May 2021 17:50:31 -0400 [thread overview]
Message-ID: <162163383147.8379.1567341725602837940.stgit@sifl> (raw)
In-Reply-To: <162163367115.8379.8459012634106035341.stgit@sifl>
WARNING - This is a work in progress, this patch, including the
description, may be incomplete or even incorrect. You have been
warned.
This patch implements two new io_uring access controls, specifically
support for controlling the io_uring "personalities" and
IORING_SETUP_SQPOLL. Controlling the sharing of io_urings themselves
is handled via the normal file/inode labeling and sharing mechanisms.
The io_uring { override_creds } permission restricts which domains
the subject domain can use to override it's own credentials.
Granting a domain the io_uring { override_creds } permission allows
it to impersonate another domain in io_uring operations.
The io_uring { sqpoll } permission restricts which domains can create
asynchronous io_uring polling threads. This is important from a
security perspective as operations queued by this asynchronous thread
inherit the credentials of the thread creator by default; if an
io_uring is shared across process/domain boundaries this could result
in one domain impersonating another. Controlling the creation of
sqpoll threads, and the sharing of io_urings across processes, allow
policy authors to restrict the ability of one domain to impersonate
another via io_uring.
As a quick summary, this patch adds a new object class with two
permissions:
io_uring { override_creds sqpoll }
These permissions can be seen in the two simple policy statements
below:
allow domA_t domB_t : io_uring { override_creds };
allow domA_t self : io_uring { sqpoll };
Signed-off-by: Paul Moore <[email protected]>
---
security/selinux/hooks.c | 67 +++++++++++++++++++++++++++++++++++
security/selinux/include/classmap.h | 2 +
2 files changed, 69 insertions(+)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index eaea837d89d1..696130972e4d 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -7115,6 +7115,68 @@ static int selinux_perf_event_write(struct perf_event *event)
}
#endif
+#ifdef CONFIG_IO_URING
+
+#if 1
+/* XXX - dump_creds() is for debugging only, remove before committing */
+static void dump_creds(const struct cred *cred)
+{
+ u32 secid;
+ char *ctx = NULL;
+ unsigned int ctx_len = 0;
+
+ security_cred_getsecid(cred, &secid);
+ if (secid)
+ security_secid_to_secctx(secid, &ctx, &ctx_len);
+
+ printk(KERN_ERR "CRED: ->security is %s\n", (ctx ? : "(error)"));
+
+ if (ctx)
+ security_release_secctx(ctx, ctx_len);
+}
+#endif
+
+/**
+ * selinux_uring_override_creds - check the requested cred override
+ * @new: the target creds
+ *
+ * Check to see if the current task is allowed to override it's credentials
+ * to service an io_uring operation.
+ */
+int selinux_uring_override_creds(const struct cred *new)
+{
+#if 1
+ /* XXX - debug only code, remove before committing */
+ pr_err("PMD: selinux_uring_override_creds()\n");
+ pr_err("PMD: >>> CURRENT\n");
+ dump_creds(current_cred());
+ pr_err("PMD: >>> NEW\n");
+ dump_creds(new);
+#endif
+ return avc_has_perm(&selinux_state, current_sid(), cred_sid(new),
+ SECCLASS_IO_URING, IO_URING__OVERRIDE_CREDS, NULL);
+}
+
+/**
+ * selinux_uring_sqpoll - check if a io_uring polling thread can be created
+ *
+ * Check to see if the current task is allowed to create a new io_uring
+ * kernel polling thread.
+ */
+int selinux_uring_sqpoll(void)
+{
+ int sid = current_sid();
+#if 1
+ /* XXX - debug only code, remove before committing */
+ pr_err("PMD: selinux_uring_sqpoll()\n");
+ pr_err("PMD: >>> CURRENT\n");
+ dump_creds(current_cred());
+#endif
+ return avc_has_perm(&selinux_state, sid, sid,
+ SECCLASS_IO_URING, IO_URING__SQPOLL, NULL);
+}
+#endif /* CONFIG_IO_URING */
+
/*
* IMPORTANT NOTE: When adding new hooks, please be careful to keep this order:
* 1. any hooks that don't belong to (2.) or (3.) below,
@@ -7353,6 +7415,11 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
LSM_HOOK_INIT(perf_event_write, selinux_perf_event_write),
#endif
+#ifdef CONFIG_IO_URING
+ LSM_HOOK_INIT(uring_override_creds, selinux_uring_override_creds),
+ LSM_HOOK_INIT(uring_sqpoll, selinux_uring_sqpoll),
+#endif
+
LSM_HOOK_INIT(locked_down, selinux_lockdown),
/*
diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h
index 62d19bccf3de..3314ad72279d 100644
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
@@ -252,6 +252,8 @@ struct security_class_mapping secclass_map[] = {
{ "integrity", "confidentiality", NULL } },
{ "anon_inode",
{ COMMON_FILE_PERMS, NULL } },
+ { "io_uring",
+ { "override_creds", "sqpoll", NULL } },
{ NULL }
};
next prev parent reply other threads:[~2021-05-21 21:50 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 21:49 [RFC PATCH 0/9] Add LSM access controls and auditing to io_uring Paul Moore
2021-05-21 21:49 ` [RFC PATCH 1/9] audit: prepare audit_context for use in calling contexts beyond syscalls Paul Moore
2021-05-21 21:49 ` [RFC PATCH 2/9] audit,io_uring,io-wq: add some basic audit support to io_uring Paul Moore
2021-05-22 0:22 ` Pavel Begunkov
2021-05-22 2:36 ` Paul Moore
2021-05-23 20:26 ` Pavel Begunkov
2021-05-24 19:59 ` Paul Moore
2021-05-25 8:27 ` Pavel Begunkov
2021-05-25 14:53 ` Paul Moore
2021-05-26 1:11 ` Jens Axboe
2021-05-26 2:04 ` Paul Moore
2021-05-26 10:19 ` Pavel Begunkov
2021-05-26 14:38 ` Paul Moore
2021-05-26 15:11 ` Steve Grubb
2021-05-26 15:17 ` Stefan Metzmacher
2021-05-26 15:49 ` Richard Guy Briggs
2021-05-26 17:22 ` Jens Axboe
2021-05-27 17:27 ` Richard Guy Briggs
2021-05-26 15:49 ` Victor Stewart
2021-05-26 16:38 ` Casey Schaufler
2021-05-26 17:15 ` Jens Axboe
2021-05-26 17:31 ` Jens Axboe
2021-05-26 17:54 ` Jens Axboe
2021-05-26 18:01 ` Jens Axboe
2021-05-26 18:44 ` Paul Moore
2021-05-26 18:57 ` Pavel Begunkov
2021-05-26 19:10 ` Paul Moore
2021-05-26 19:44 ` Jens Axboe
2021-05-26 20:19 ` Paul Moore
2021-05-28 16:02 ` Paul Moore
2021-06-02 8:26 ` Pavel Begunkov
2021-06-02 15:46 ` Richard Guy Briggs
2021-06-03 10:39 ` Pavel Begunkov
2021-06-02 19:46 ` Paul Moore
2021-06-03 10:51 ` Pavel Begunkov
2021-06-03 15:54 ` Casey Schaufler
2021-06-03 15:54 ` Jens Axboe
2021-06-04 5:04 ` Paul Moore
2021-05-26 18:38 ` Paul Moore
2021-06-02 17:29 ` [RFC PATCH 2/9] audit, io_uring, io-wq: " Richard Guy Briggs
2021-06-02 20:46 ` Paul Moore
2021-08-25 1:21 ` Richard Guy Briggs
2021-08-25 19:41 ` Paul Moore
2021-05-21 21:50 ` [RFC PATCH 3/9] audit: dev/test patch to force io_uring auditing Paul Moore
2021-05-21 21:50 ` [RFC PATCH 4/9] audit: add filtering for io_uring records Paul Moore
2021-05-28 22:35 ` Richard Guy Briggs
2021-05-30 15:26 ` Paul Moore
2021-05-31 13:44 ` Richard Guy Briggs
2021-06-02 1:40 ` Paul Moore
2021-06-02 15:37 ` Richard Guy Briggs
2021-06-02 17:20 ` Paul Moore
2021-05-31 13:44 ` [PATCH 1/2] audit: add filtering for io_uring records, addendum Richard Guy Briggs
2021-05-31 16:08 ` kernel test robot
2021-05-31 17:38 ` kernel test robot
2021-06-07 23:15 ` Paul Moore
2021-06-08 12:55 ` Richard Guy Briggs
2021-06-09 2:45 ` Paul Moore
2021-05-31 13:44 ` [PATCH 2/2] audit: block PERM fields being used with io_uring filtering Richard Guy Briggs
2021-05-21 21:50 ` [RFC PATCH 5/9] fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure() Paul Moore
2021-05-21 21:50 ` [RFC PATCH 6/9] io_uring: convert io_uring to the secure anon inode interface Paul Moore
2021-05-21 21:50 ` [RFC PATCH 7/9] lsm,io_uring: add LSM hooks to io_uring Paul Moore
2021-05-26 14:48 ` Stefan Metzmacher
2021-05-26 20:45 ` Paul Moore
2021-05-21 21:50 ` Paul Moore [this message]
2021-05-21 21:50 ` [RFC PATCH 9/9] Smack: Brutalist io_uring support with debug Paul Moore
2021-05-22 0:53 ` [RFC PATCH 0/9] Add LSM access controls and auditing to io_uring Tetsuo Handa
2021-05-22 2:06 ` Paul Moore
2021-05-26 15:00 ` Jeff Moyer
2021-05-26 18:49 ` Paul Moore
2021-05-26 19:07 ` Jeff Moyer
2021-05-26 19:10 ` Paul Moore
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