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From: Paul Moore <paul@paul-moore.com>
To: Casey Schaufler <casey@schaufler-ca.com>,
	John Johansen <john.johansen@canonical.com>
Cc: selinux@vger.kernel.org, linux-security-module@vger.kernel.org,
	linux-audit@redhat.com
Subject: [RFC PATCH 3/4] smack: differentiate between subjective and objective task credentials
Date: Fri, 19 Feb 2021 18:29:17 -0500
Message-ID: <161377735771.87807.8998552586584751981.stgit@sifl> (raw)
In-Reply-To: <161377712068.87807.12246856567527156637.stgit@sifl>

With the split of the security_task_getsecid() into subjective and
objective variants it's time to update Smack to ensure it is using
the correct task creds.

Signed-off-by: Paul Moore <paul@paul-moore.com>
---
 security/smack/smack.h     |   18 +++++++++++++++++-
 security/smack/smack_lsm.c |   40 +++++++++++++++++++++++++++-------------
 2 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index a9768b12716bf..08f9cb80655ce 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -383,7 +383,23 @@ static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
 	return tsp->smk_task;
 }
 
-static inline struct smack_known *smk_of_task_struct(
+static inline struct smack_known *smk_of_task_struct_subj(
+						const struct task_struct *t)
+{
+	struct smack_known *skp;
+	const struct cred *cred;
+
+	rcu_read_lock();
+
+	cred = rcu_dereference(t->cred);
+	skp = smk_of_task(smack_cred(cred));
+
+	rcu_read_unlock();
+
+	return skp;
+}
+
+static inline struct smack_known *smk_of_task_struct_obj(
 						const struct task_struct *t)
 {
 	struct smack_known *skp;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 2bb354ef2c4a9..ea1a82742e8ba 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -159,7 +159,7 @@ static int smk_bu_current(char *note, struct smack_known *oskp,
 static int smk_bu_task(struct task_struct *otp, int mode, int rc)
 {
 	struct task_smack *tsp = smack_cred(current_cred());
-	struct smack_known *smk_task = smk_of_task_struct(otp);
+	struct smack_known *smk_task = smk_of_task_struct_obj(otp);
 	char acc[SMK_NUM_ACCESS_TYPE + 1];
 
 	if (rc <= 0)
@@ -479,7 +479,7 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 {
 	struct smack_known *skp;
 
-	skp = smk_of_task_struct(ctp);
+	skp = smk_of_task_struct_obj(ctp);
 
 	return smk_ptrace_rule_check(current, skp, mode, __func__);
 }
@@ -2031,7 +2031,7 @@ static int smk_curacc_on_task(struct task_struct *p, int access,
 				const char *caller)
 {
 	struct smk_audit_info ad;
-	struct smack_known *skp = smk_of_task_struct(p);
+	struct smack_known *skp = smk_of_task_struct_subj(p);
 	int rc;
 
 	smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
@@ -2076,15 +2076,29 @@ static int smack_task_getsid(struct task_struct *p)
 }
 
 /**
- * smack_task_getsecid - get the secid of the task
- * @p: the object task
+ * smack_task_getsecid_subj - get the subjective secid of the task
+ * @p: the task
  * @secid: where to put the result
  *
- * Sets the secid to contain a u32 version of the smack label.
+ * Sets the secid to contain a u32 version of the task's subjective smack label.
+ */
+static void smack_task_getsecid_subj(struct task_struct *p, u32 *secid)
+{
+	struct smack_known *skp = smk_of_task_struct_subj(p);
+
+	*secid = skp->smk_secid;
+}
+
+/**
+ * smack_task_getsecid_obj - get the objective secid of the task
+ * @p: the task
+ * @secid: where to put the result
+ *
+ * Sets the secid to contain a u32 version of the task's objective smack label.
  */
-static void smack_task_getsecid(struct task_struct *p, u32 *secid)
+static void smack_task_getsecid_obj(struct task_struct *p, u32 *secid)
 {
-	struct smack_known *skp = smk_of_task_struct(p);
+	struct smack_known *skp = smk_of_task_struct_obj(p);
 
 	*secid = skp->smk_secid;
 }
@@ -2172,7 +2186,7 @@ static int smack_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 {
 	struct smk_audit_info ad;
 	struct smack_known *skp;
-	struct smack_known *tkp = smk_of_task_struct(p);
+	struct smack_known *tkp = smk_of_task_struct_obj(p);
 	int rc;
 
 	if (!sig)
@@ -2210,7 +2224,7 @@ static int smack_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
 {
 	struct inode_smack *isp = smack_inode(inode);
-	struct smack_known *skp = smk_of_task_struct(p);
+	struct smack_known *skp = smk_of_task_struct_obj(p);
 
 	isp->smk_inode = skp;
 	isp->smk_flags |= SMK_INODE_INSTANT;
@@ -3481,7 +3495,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
  */
 static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 {
-	struct smack_known *skp = smk_of_task_struct(p);
+	struct smack_known *skp = smk_of_task_struct_subj(p);
 	char *cp;
 	int slen;
 
@@ -4755,8 +4769,8 @@ static struct security_hook_list smack_hooks[] __lsm_ro_after_init = {
 	LSM_HOOK_INIT(task_setpgid, smack_task_setpgid),
 	LSM_HOOK_INIT(task_getpgid, smack_task_getpgid),
 	LSM_HOOK_INIT(task_getsid, smack_task_getsid),
-	LSM_HOOK_INIT(task_getsecid_subj, smack_task_getsecid),
-	LSM_HOOK_INIT(task_getsecid_obj, smack_task_getsecid),
+	LSM_HOOK_INIT(task_getsecid_subj, smack_task_getsecid_subj),
+	LSM_HOOK_INIT(task_getsecid_obj, smack_task_getsecid_obj),
 	LSM_HOOK_INIT(task_setnice, smack_task_setnice),
 	LSM_HOOK_INIT(task_setioprio, smack_task_setioprio),
 	LSM_HOOK_INIT(task_getioprio, smack_task_getioprio),

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  parent reply index

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-19 23:28 [RFC PATCH 0/4] Split security_task_getsecid() into subj and obj variants Paul Moore
2021-02-19 23:29 ` [RFC PATCH 1/4] lsm: separate security_task_getsecid() into subjective and objective variants Paul Moore
2021-02-20  2:55   ` James Morris
2021-02-20 14:44     ` Paul Moore
2021-03-04 10:04       ` Jeffrey Vander Stoep
2021-03-04 23:43         ` Paul Moore
2021-03-10  8:21           ` Jeffrey Vander Stoep
2021-03-11  1:56             ` Paul Moore
2021-02-21 12:51   ` John Johansen
2021-02-21 22:09     ` Paul Moore
2021-03-04  0:44     ` Paul Moore
2021-03-10  0:28       ` Paul Moore
2021-03-10  3:09         ` John Johansen
2021-02-24 16:49   ` Mimi Zohar
2021-03-08 19:25   ` Richard Guy Briggs
2021-03-10  0:23     ` Paul Moore
2021-03-10  1:03   ` John Johansen
2021-03-11  1:55     ` Paul Moore
2021-02-19 23:29 ` [RFC PATCH 2/4] selinux: clarify task subjective and objective credentials Paul Moore
2021-02-21 12:55   ` John Johansen
2021-03-08 19:26   ` Richard Guy Briggs
2021-03-10  3:05   ` John Johansen
2021-03-11  4:32     ` Paul Moore
2021-03-17 22:56       ` Paul Moore
2021-02-19 23:29 ` Paul Moore [this message]
2021-02-21 12:56   ` [RFC PATCH 3/4] smack: differentiate between subjective and objective task credentials John Johansen
2021-03-08 19:26   ` Richard Guy Briggs
2021-03-10  1:04   ` John Johansen
2021-02-19 23:29 ` [RFC PATCH 4/4] apparmor: " Paul Moore
2021-02-21 12:57   ` John Johansen
2021-02-21 22:12     ` Paul Moore
2021-02-20  1:49 ` [RFC PATCH 0/4] Split security_task_getsecid() into subj and obj variants Casey Schaufler
2021-02-20 14:41   ` Paul Moore
2021-02-22 23:58     ` Casey Schaufler
2021-02-23 14:14       ` Mimi Zohar
2021-02-24  0:03         ` Paul Moore
2021-03-04  0:46       ` Paul Moore
2021-03-04  2:21         ` Casey Schaufler
2021-03-04 23:41           ` Paul Moore

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