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From: Paul Moore <paul@paul-moore.com>
To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
	linux-audit@redhat.com, io-uring@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	Jens Axboe <axboe@kernel.dk>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [RFC PATCH 9/9] Smack: Brutalist io_uring support with debug
Date: Fri, 21 May 2021 17:50:37 -0400	[thread overview]
Message-ID: <162163383761.8379.7421085717625472402.stgit@sifl> (raw)
In-Reply-To: <162163367115.8379.8459012634106035341.stgit@sifl>

From: Casey Schaufler <casey@schaufler-ca.com>

Add Smack privilege checks for io_uring. Use CAP_MAC_OVERRIDE
for the override_creds case and CAP_MAC_ADMIN for creating a
polling thread. These choices are based on conjecture regarding
the intent of the surrounding code.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
---
 security/smack/smack_lsm.c |   64 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 223a6da0e6dc..f6423c0096e9 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4691,6 +4691,66 @@ static int smack_dentry_create_files_as(struct dentry *dentry, int mode,
 	return 0;
 }
 
+#ifdef CONFIG_IO_URING
+/**
+ * smack_uring_override_creds - Is io_uring cred override allowed?
+ * @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 smack_uring_override_creds(const struct cred *new)
+{
+	struct task_smack *tsp = smack_cred(current_cred());
+	struct task_smack *nsp = smack_cred(new);
+
+#if 1
+	if (tsp->smk_task == nsp->smk_task)
+		pr_info("%s: Smack matches %s\n", __func__,
+			tsp->smk_task->smk_known);
+	else
+		pr_info("%s: Smack override check %s to %s\n", __func__,
+			tsp->smk_task->smk_known, nsp->smk_task->smk_known);
+#endif
+	/*
+	 * Allow the degenerate case where the new Smack value is
+	 * the same as the current Smack value.
+	 */
+	if (tsp->smk_task == nsp->smk_task)
+		return 0;
+
+#if 1
+	pr_info("%s: Smack sqpoll %s\n", __func__,
+		smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()) ?
+		"ok by Smack" : "disallowed (No CAP_MAC_OVERRIDE)");
+#endif
+	if (smack_privileged_cred(CAP_MAC_OVERRIDE, current_cred()))
+		return 0;
+
+	return -EPERM;
+}
+
+/**
+ * smack_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 smack_uring_sqpoll(void)
+{
+#if 1
+	pr_info("%s: Smack new ring %s\n", __func__,
+		smack_privileged_cred(CAP_MAC_ADMIN, current_cred()) ?
+		"ok by Smack" : "disallowed (No CAP_MAC_ADMIN)");
+#endif
+	if (smack_privileged_cred(CAP_MAC_ADMIN, current_cred()))
+		return 0;
+
+	return -EPERM;
+}
+
+#endif /* CONFIG_IO_URING */
+
 struct lsm_blob_sizes smack_blob_sizes __lsm_ro_after_init = {
 	.lbs_cred = sizeof(struct task_smack),
 	.lbs_file = sizeof(struct smack_known *),
@@ -4843,6 +4903,10 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(inode_copy_up, smack_inode_copy_up),
 	LSM_HOOK_INIT(inode_copy_up_xattr, smack_inode_copy_up_xattr),
 	LSM_HOOK_INIT(dentry_create_files_as, smack_dentry_create_files_as),
+#ifdef CONFIG_IO_URING
+	LSM_HOOK_INIT(uring_override_creds, smack_uring_override_creds),
+	LSM_HOOK_INIT(uring_sqpoll, smack_uring_sqpoll),
+#endif
 };
 
 

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  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   ` [RFC PATCH 2/9] audit,io_uring,io-wq: " 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                   ` [RFC PATCH 2/9] audit, io_uring, io-wq: " Steve Grubb
2021-05-26 15:17                   ` [RFC PATCH 2/9] audit,io_uring,io-wq: " 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 ` [RFC PATCH 8/9] selinux: add support for the io_uring access controls Paul Moore
2021-05-21 21:50 ` Paul Moore [this message]
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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