Smack: Bring-up access mode
People keep asking me for permissive mode, and I keep saying "no".
Permissive mode is wrong for more reasons than I can enumerate,
but the compelling one is that it's once on, never off.
Nonetheless, there is an argument to be made for running a
process with lots of permissions, logging which are required,
and then locking the process down. There wasn't a way to do
that with Smack, but this provides it.
The notion is that you start out by giving the process an
appropriate Smack label, such as "ATBirds". You create rules
with a wide range of access and the "b" mode. On Tizen it
might be:
ATBirds System rwxalb
ATBirds User rwxalb
ATBirds _ rwxalb
User ATBirds wb
System ATBirds wb
Accesses that fail will generate audit records. Accesses
that succeed because of rules marked with a "b" generate
log messages identifying the rule, the program and as much
object information as is convenient.
When the system is properly configured and the programs
brought in line with the labeling scheme the "b" mode can
be removed from the rules. When the system is ready for
production the facility can be configured out.
This provides the developer the convenience of permissive
mode without creating a system that looks like it is
enforcing a policy while it is not.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 7091b46..154548e 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -54,6 +54,149 @@
LIST_HEAD(smk_ipv6_port_list);
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static void smk_bu_mode(int mode, char *s)
+{
+ int i = 0;
+
+ if (mode & MAY_READ)
+ s[i++] = 'r';
+ if (mode & MAY_WRITE)
+ s[i++] = 'w';
+ if (mode & MAY_EXEC)
+ s[i++] = 'x';
+ if (mode & MAY_APPEND)
+ s[i++] = 'a';
+ if (mode & MAY_TRANSMUTE)
+ s[i++] = 't';
+ if (mode & MAY_LOCK)
+ s[i++] = 'l';
+ if (i == 0)
+ s[i++] = '-';
+ s[i] = '\0';
+}
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_note(char *note, struct smack_known *sskp, char *osp,
+ int mode, int rc)
+{
+ char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+ if (rc <= 0)
+ return rc;
+
+ smk_bu_mode(mode, acc);
+ pr_info("Smack Bringup: (%s %s %s) %s\n",
+ sskp->smk_known, osp, acc, note);
+ return 0;
+}
+#else
+#define smk_bu_note(note, sskp, osp, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_current(char *note, char *osp, int mode, int rc)
+{
+ struct task_smack *tsp = current_security();
+ char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+ if (rc <= 0)
+ return rc;
+
+ smk_bu_mode(mode, acc);
+ pr_info("Smack Bringup: (%s %s %s) %s %s\n",
+ tsp->smk_task->smk_known, osp, acc, current->comm, note);
+ return 0;
+}
+#else
+#define smk_bu_current(note, osp, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_task(struct task_struct *otp, int mode, int rc)
+{
+ struct task_smack *tsp = current_security();
+ struct task_smack *otsp = task_security(otp);
+ char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+ if (rc <= 0)
+ return rc;
+
+ smk_bu_mode(mode, acc);
+ pr_info("Smack Bringup: (%s %s %s) %s to %s\n",
+ tsp->smk_task->smk_known, otsp->smk_task->smk_known, acc,
+ current->comm, otp->comm);
+ return 0;
+}
+#else
+#define smk_bu_task(otp, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_inode(struct inode *inode, int mode, int rc)
+{
+ struct task_smack *tsp = current_security();
+ char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+ if (rc <= 0)
+ return rc;
+
+ smk_bu_mode(mode, acc);
+ pr_info("Smack Bringup: (%s %s %s) inode=(%s %ld) %s\n",
+ tsp->smk_task->smk_known, smk_of_inode(inode), acc,
+ inode->i_sb->s_id, inode->i_ino, current->comm);
+ return 0;
+}
+#else
+#define smk_bu_inode(inode, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_file(struct file *file, int mode, int rc)
+{
+ struct task_smack *tsp = current_security();
+ struct smack_known *sskp = tsp->smk_task;
+ struct inode *inode = file->f_inode;
+ char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+ if (rc <= 0)
+ return rc;
+
+ smk_bu_mode(mode, acc);
+ pr_info("Smack Bringup: (%s %s %s) file=(%s %ld %s) %s\n",
+ sskp->smk_known, (char *)file->f_security, acc,
+ inode->i_sb->s_id, inode->i_ino, file->f_dentry->d_name.name,
+ current->comm);
+ return 0;
+}
+#else
+#define smk_bu_file(file, mode, RC) (RC)
+#endif
+
+#ifdef CONFIG_SECURITY_SMACK_BRINGUP
+static int smk_bu_credfile(const struct cred *cred, struct file *file,
+ int mode, int rc)
+{
+ struct task_smack *tsp = cred->security;
+ struct smack_known *sskp = tsp->smk_task;
+ struct inode *inode = file->f_inode;
+ char acc[SMK_NUM_ACCESS_TYPE + 1];
+
+ if (rc <= 0)
+ return rc;
+
+ smk_bu_mode(mode, acc);
+ pr_info("Smack Bringup: (%s %s %s) file=(%s %ld %s) %s\n",
+ sskp->smk_known, smk_of_inode(inode), acc,
+ inode->i_sb->s_id, inode->i_ino, file->f_dentry->d_name.name,
+ current->comm);
+ return 0;
+}
+#else
+#define smk_bu_credfile(cred, file, mode, RC) (RC)
+#endif
+
/**
* smk_fetch - Fetch the smack label from a file.
* @ip: a pointer to the inode
@@ -507,6 +650,7 @@
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
+ rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
return rc;
}
@@ -697,11 +841,13 @@
isp = smk_of_inode(old_dentry->d_inode);
rc = smk_curacc(isp, MAY_WRITE, &ad);
+ rc = smk_bu_inode(old_dentry->d_inode, MAY_WRITE, rc);
if (rc == 0 && new_dentry->d_inode != NULL) {
isp = smk_of_inode(new_dentry->d_inode);
smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
rc = smk_curacc(isp, MAY_WRITE, &ad);
+ rc = smk_bu_inode(new_dentry->d_inode, MAY_WRITE, rc);
}
return rc;
@@ -728,6 +874,7 @@
* You need write access to the thing you're unlinking
*/
rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
+ rc = smk_bu_inode(ip, MAY_WRITE, rc);
if (rc == 0) {
/*
* You also need write access to the containing directory
@@ -735,6 +882,7 @@
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
smk_ad_setfield_u_fs_inode(&ad, dir);
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+ rc = smk_bu_inode(dir, MAY_WRITE, rc);
}
return rc;
}
@@ -759,6 +907,7 @@
* You need write access to the thing you're removing
*/
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+ rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
if (rc == 0) {
/*
* You also need write access to the containing directory
@@ -766,6 +915,7 @@
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
smk_ad_setfield_u_fs_inode(&ad, dir);
rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+ rc = smk_bu_inode(dir, MAY_WRITE, rc);
}
return rc;
@@ -797,11 +947,13 @@
isp = smk_of_inode(old_dentry->d_inode);
rc = smk_curacc(isp, MAY_READWRITE, &ad);
+ rc = smk_bu_inode(old_dentry->d_inode, MAY_READWRITE, rc);
if (rc == 0 && new_dentry->d_inode != NULL) {
isp = smk_of_inode(new_dentry->d_inode);
smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
rc = smk_curacc(isp, MAY_READWRITE, &ad);
+ rc = smk_bu_inode(new_dentry->d_inode, MAY_READWRITE, rc);
}
return rc;
}
@@ -819,6 +971,7 @@
{
struct smk_audit_info ad;
int no_block = mask & MAY_NOT_BLOCK;
+ int rc;
mask &= (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND);
/*
@@ -832,7 +985,9 @@
return -ECHILD;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
smk_ad_setfield_u_fs_inode(&ad, inode);
- return smk_curacc(smk_of_inode(inode), mask, &ad);
+ rc = smk_curacc(smk_of_inode(inode), mask, &ad);
+ rc = smk_bu_inode(inode, mask, rc);
+ return rc;
}
/**
@@ -845,6 +1000,8 @@
static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct smk_audit_info ad;
+ int rc;
+
/*
* Need to allow for clearing the setuid bit.
*/
@@ -853,7 +1010,9 @@
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
- return smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+ rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+ rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
+ return rc;
}
/**
@@ -867,13 +1026,16 @@
{
struct smk_audit_info ad;
struct path path;
+ int rc;
path.dentry = dentry;
path.mnt = mnt;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, path);
- return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+ rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+ rc = smk_bu_inode(dentry->d_inode, MAY_READ, rc);
+ return rc;
}
/**
@@ -932,8 +1094,10 @@
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
- if (rc == 0)
+ if (rc == 0) {
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+ rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
+ }
return rc;
}
@@ -993,11 +1157,14 @@
static int smack_inode_getxattr(struct dentry *dentry, const char *name)
{
struct smk_audit_info ad;
+ int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
- return smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+ rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_READ, &ad);
+ rc = smk_bu_inode(dentry->d_inode, MAY_READ, rc);
+ return rc;
}
/**
@@ -1033,6 +1200,7 @@
smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+ rc = smk_bu_inode(dentry->d_inode, MAY_WRITE, rc);
if (rc != 0)
return rc;
@@ -1213,11 +1381,15 @@
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
- if (_IOC_DIR(cmd) & _IOC_WRITE)
+ if (_IOC_DIR(cmd) & _IOC_WRITE) {
rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
+ rc = smk_bu_file(file, MAY_WRITE, rc);
+ }
- if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ))
+ if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
rc = smk_curacc(file->f_security, MAY_READ, &ad);
+ rc = smk_bu_file(file, MAY_READ, rc);
+ }
return rc;
}
@@ -1232,10 +1404,13 @@
static int smack_file_lock(struct file *file, unsigned int cmd)
{
struct smk_audit_info ad;
+ int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
- return smk_curacc(file->f_security, MAY_LOCK, &ad);
+ rc = smk_curacc(file->f_security, MAY_LOCK, &ad);
+ rc = smk_bu_file(file, MAY_LOCK, rc);
+ return rc;
}
/**
@@ -1265,12 +1440,14 @@
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_curacc(file->f_security, MAY_LOCK, &ad);
+ rc = smk_bu_file(file, MAY_LOCK, rc);
break;
case F_SETOWN:
case F_SETSIG:
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_curacc(file->f_security, MAY_WRITE, &ad);
+ rc = smk_bu_file(file, MAY_WRITE, rc);
break;
default:
break;
@@ -1425,6 +1602,7 @@
/* we don't log here as rc can be overriden */
skp = smk_find_entry(file->f_security);
rc = smk_access(skp, tkp->smk_known, MAY_WRITE, NULL);
+ rc = smk_bu_note("sigiotask", skp, tkp->smk_known, MAY_WRITE, rc);
if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
rc = 0;
@@ -1442,6 +1620,7 @@
*/
static int smack_file_receive(struct file *file)
{
+ int rc;
int may = 0;
struct smk_audit_info ad;
@@ -1455,7 +1634,9 @@
if (file->f_mode & FMODE_WRITE)
may |= MAY_WRITE;
- return smk_curacc(file->f_security, may, &ad);
+ rc = smk_curacc(file->f_security, may, &ad);
+ rc = smk_bu_file(file, may, rc);
+ return rc;
}
/**
@@ -1485,6 +1666,7 @@
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
smk_ad_setfield_u_fs_path(&ad, file->f_path);
rc = smk_access(tsp->smk_task, isp->smk_inode, MAY_READ, &ad);
+ rc = smk_bu_credfile(cred, file, MAY_READ, rc);
if (rc == 0)
file->f_security = isp->smk_inode;
@@ -1641,10 +1823,13 @@
{
struct smk_audit_info ad;
struct smack_known *skp = smk_of_task(task_security(p));
+ int rc;
smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, p);
- return smk_curacc(skp->smk_known, access, &ad);
+ rc = smk_curacc(skp->smk_known, access, &ad);
+ rc = smk_bu_task(p, access, rc);
+ return rc;
}
/**
@@ -1798,6 +1983,7 @@
struct smk_audit_info ad;
struct smack_known *skp;
struct smack_known *tkp = smk_of_task(task_security(p));
+ int rc;
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
smk_ad_setfield_u_tsk(&ad, p);
@@ -1805,15 +1991,20 @@
* Sending a signal requires that the sender
* can write the receiver.
*/
- if (secid == 0)
- return smk_curacc(tkp->smk_known, MAY_WRITE, &ad);
+ if (secid == 0) {
+ rc = smk_curacc(tkp->smk_known, MAY_WRITE, &ad);
+ rc = smk_bu_task(p, MAY_WRITE, rc);
+ return rc;
+ }
/*
* If the secid isn't 0 we're dealing with some USB IO
* specific behavior. This is not clean. For one thing
* we can't take privilege into account.
*/
skp = smack_from_secid(secid);
- return smk_access(skp, tkp->smk_known, MAY_WRITE, &ad);
+ rc = smk_access(skp, tkp->smk_known, MAY_WRITE, &ad);
+ rc = smk_bu_note("USB signal", skp, tkp->smk_known, MAY_WRITE, rc);
+ return rc;
}
/**
@@ -2005,6 +2196,7 @@
sk_lbl = SMACK_UNLABELED_SOCKET;
skp = ssp->smk_out;
rc = smk_access(skp, hostsp, MAY_WRITE, &ad);
+ rc = smk_bu_note("IPv4 host check", skp, hostsp, MAY_WRITE, rc);
} else {
sk_lbl = SMACK_CIPSO_SOCKET;
rc = 0;
@@ -2107,6 +2299,7 @@
unsigned short port = 0;
char *object;
struct smk_audit_info ad;
+ int rc;
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
#endif
@@ -2160,7 +2353,9 @@
else
ad.a.u.net->v6info.daddr = address->sin6_addr;
#endif
- return smk_access(skp, object, MAY_WRITE, &ad);
+ rc = smk_access(skp, object, MAY_WRITE, &ad);
+ rc = smk_bu_note("IPv6 port check", skp, object, MAY_WRITE, rc);
+ return rc;
}
/**
@@ -2399,12 +2594,15 @@
{
char *ssp = smack_of_shm(shp);
struct smk_audit_info ad;
+ int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = shp->shm_perm.id;
#endif
- return smk_curacc(ssp, access, &ad);
+ rc = smk_curacc(ssp, access, &ad);
+ rc = smk_bu_current("shm", ssp, access, rc);
+ return rc;
}
/**
@@ -2523,12 +2721,15 @@
{
char *ssp = smack_of_sem(sma);
struct smk_audit_info ad;
+ int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = sma->sem_perm.id;
#endif
- return smk_curacc(ssp, access, &ad);
+ rc = smk_curacc(ssp, access, &ad);
+ rc = smk_bu_current("sem", ssp, access, rc);
+ return rc;
}
/**
@@ -2653,12 +2854,15 @@
{
char *msp = smack_of_msq(msq);
struct smk_audit_info ad;
+ int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = msq->q_perm.id;
#endif
- return smk_curacc(msp, access, &ad);
+ rc = smk_curacc(msp, access, &ad);
+ rc = smk_bu_current("msq", msp, access, rc);
+ return rc;
}
/**
@@ -2754,12 +2958,15 @@
char *isp = ipp->security;
int may = smack_flags_to_may(flag);
struct smk_audit_info ad;
+ int rc;
#ifdef CONFIG_AUDIT
smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
ad.a.u.ipc_id = ipp->id;
#endif
- return smk_curacc(isp, may, &ad);
+ rc = smk_curacc(isp, may, &ad);
+ rc = smk_bu_current("svipc", isp, may, rc);
+ return rc;
}
/**
@@ -3092,8 +3299,13 @@
smk_ad_setfield_u_net_sk(&ad, other);
#endif
rc = smk_access(skp, okp->smk_known, MAY_WRITE, &ad);
- if (rc == 0)
+ rc = smk_bu_note("UDS connect", skp, okp->smk_known,
+ MAY_WRITE, rc);
+ if (rc == 0) {
rc = smk_access(okp, okp->smk_known, MAY_WRITE, NULL);
+ rc = smk_bu_note("UDS connect", okp, okp->smk_known,
+ MAY_WRITE, rc);
+ }
}
/*
@@ -3121,6 +3333,7 @@
struct socket_smack *osp = other->sk->sk_security;
struct smack_known *skp;
struct smk_audit_info ad;
+ int rc;
#ifdef CONFIG_AUDIT
struct lsm_network_audit net;
@@ -3133,7 +3346,10 @@
return 0;
skp = ssp->smk_out;
- return smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad);
+ rc = smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad);
+ rc = smk_bu_note("UDS send", skp, osp->smk_in->smk_known,
+ MAY_WRITE, rc);
+ return rc;
}
/**
@@ -3348,6 +3564,8 @@
* for networking.
*/
rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
+ rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in->smk_known,
+ MAY_WRITE, rc);
if (rc != 0)
netlbl_skbuff_err(skb, rc, 0);
break;
@@ -3528,6 +3746,8 @@
* here. Read access is not required.
*/
rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
+ rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in->smk_known,
+ MAY_WRITE, rc);
if (rc != 0)
return rc;
@@ -3631,6 +3851,7 @@
struct smk_audit_info ad;
struct smack_known *tkp = smk_of_task(cred->security);
int request = 0;
+ int rc;
keyp = key_ref_to_ptr(key_ref);
if (keyp == NULL)
@@ -3655,7 +3876,9 @@
request = MAY_READ;
if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
request = MAY_WRITE;
- return smk_access(tkp, keyp->security, request, &ad);
+ rc = smk_access(tkp, keyp->security, request, &ad);
+ rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
+ return rc;
}
#endif /* CONFIG_KEYS */