@@ -36,6 +36,14 @@ for SELinux would be in /proc/.../attr/selinux. Using the files
found directly in /proc/.../attr (e.g. current) should be avoided.
These files remain as legacy interfaces.
+The files named "context" in the attr directories contain the
+same information as the "current" files, but formatted to
+identify the module it comes from.
+
+if selinux is the active security module:
+ /proc/self/attr/context could contain selinux='unconfined_t'
+ /proc/self/attr/selinux/context could contain selinux='unconfined_t'
+
Based on https://lkml.org/lkml/2007/10/26/215,
a new LSM is accepted into the kernel when its intent (a description of
what it tries to protect against and in what cases one would expect to
@@ -2532,6 +2532,7 @@ static const struct pid_entry selinux_attr_dir_stuff[] = {
ATTR("selinux", "fscreate", S_IRUGO|S_IWUGO),
ATTR("selinux", "keycreate", S_IRUGO|S_IWUGO),
ATTR("selinux", "sockcreate", S_IRUGO|S_IWUGO),
+ ATTR("selinux", "context", S_IRUGO|S_IWUGO),
};
LSM_DIR_OPS(selinux);
#endif
@@ -2539,6 +2540,7 @@ LSM_DIR_OPS(selinux);
#ifdef CONFIG_SECURITY_SMACK
static const struct pid_entry smack_attr_dir_stuff[] = {
ATTR("smack", "current", S_IRUGO|S_IWUGO),
+ ATTR("smack", "context", S_IRUGO|S_IWUGO),
};
LSM_DIR_OPS(smack);
#endif
@@ -2548,6 +2550,7 @@ static const struct pid_entry apparmor_attr_dir_stuff[] = {
ATTR("apparmor", "current", S_IRUGO|S_IWUGO),
ATTR("apparmor", "prev", S_IRUGO),
ATTR("apparmor", "exec", S_IRUGO|S_IWUGO),
+ ATTR("apparmor", "context", S_IRUGO|S_IWUGO),
};
LSM_DIR_OPS(apparmor);
#endif
@@ -2559,6 +2562,7 @@ static const struct pid_entry attr_dir_stuff[] = {
ATTR(NULL, "fscreate", S_IRUGO|S_IWUGO),
ATTR(NULL, "keycreate", S_IRUGO|S_IWUGO),
ATTR(NULL, "sockcreate", S_IRUGO|S_IWUGO),
+ ATTR(NULL, "context", S_IRUGO|S_IWUGO),
#ifdef CONFIG_SECURITY_SELINUX
DIR("selinux", S_IRUGO|S_IXUGO,
proc_selinux_attr_dir_inode_ops, proc_selinux_attr_dir_ops),
@@ -476,9 +476,13 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
const struct cred *cred = get_task_cred(task);
struct aa_task_cxt *cxt = cred_cxt(cred);
struct aa_profile *profile = NULL;
+ char *vp;
+ char *np;
if (strcmp(name, "current") == 0)
profile = aa_get_newest_profile(cxt->profile);
+ else if (strcmp(name, "context") == 0)
+ profile = aa_get_newest_profile(cxt->profile);
else if (strcmp(name, "prev") == 0 && cxt->previous)
profile = aa_get_newest_profile(cxt->previous);
else if (strcmp(name, "exec") == 0 && cxt->onexec)
@@ -486,9 +490,29 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
else
error = -EINVAL;
- if (profile)
- error = aa_getprocattr(profile, value);
+ if (profile == NULL)
+ goto put_out;
+
+ error = aa_getprocattr(profile, &vp);
+ if (error < 0)
+ goto put_out;
+
+ if (strcmp(name, "context") == 0) {
+ *value = kasprintf(GFP_KERNEL, "apparmor='%s'", vp);
+ if (*value == NULL) {
+ error = -ENOMEM;
+ goto put_out;
+ }
+ np = strchr(*value, '\n');
+ if (np != NULL) {
+ np[0] = '\'';
+ np[1] = '\0';
+ }
+ error = strlen(*value);
+ } else
+ *value = vp;
+put_out:
aa_put_profile(profile);
put_cred(cred);
@@ -530,7 +554,7 @@ static int apparmor_setprocattr(struct task_struct *task, char *name,
return -EINVAL;
arg_size = size - (args - (char *) value);
- if (strcmp(name, "current") == 0) {
+ if (strcmp(name, "current") == 0 || strcmp(name, "context") == 0) {
if (strcmp(command, "changehat") == 0) {
error = aa_setprocattr_changehat(args, arg_size,
!AA_DO_TEST);
@@ -552,7 +576,10 @@ static int apparmor_setprocattr(struct task_struct *task, char *name,
else
goto fail;
} else
- /* only support the "current" and "exec" process attributes */
+ /*
+ * only support the "current", context and "exec"
+ * process attributes
+ */
return -EINVAL;
if (!error)
@@ -1186,8 +1186,47 @@ int security_getprocattr(struct task_struct *p, const char *lsm, char *name,
char **value)
{
struct security_hook_list *hp;
+ char *vp;
+ char *cp = NULL;
int rc = -EINVAL;
+ int trc;
+ /*
+ * "context" requires work here in addition to what
+ * the modules provide.
+ */
+ if (strcmp(name, "context") == 0) {
+ *value = NULL;
+ list_for_each_entry(hp,
+ &security_hook_heads.getprocattr, list) {
+ if (lsm != NULL && strcmp(lsm, hp->lsm))
+ continue;
+ trc = hp->hook.getprocattr(p, "context", &vp);
+ if (trc == -ENOENT)
+ continue;
+ if (trc <= 0) {
+ kfree(*value);
+ return trc;
+ }
+ rc = trc;
+ if (*value == NULL) {
+ *value = vp;
+ } else {
+ cp = kasprintf(GFP_KERNEL, "%s,%s", *value, vp);
+ if (cp == NULL) {
+ kfree(*value);
+ kfree(vp);
+ return -ENOMEM;
+ }
+ kfree(*value);
+ kfree(vp);
+ *value = cp;
+ }
+ }
+ if (rc > 0)
+ return strlen(*value);
+ return rc;
+ }
list_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
if (lsm != NULL && strcmp(lsm, hp->lsm))
@@ -1204,7 +1243,76 @@ int security_setprocattr(struct task_struct *p, const char *lsm, char *name,
{
struct security_hook_list *hp;
int rc = -EINVAL;
+ char *local;
+ char *cp;
+ int slen;
+ int failed = 0;
+
+ /*
+ * If lsm is NULL look at all the modules to find one
+ * that processes name. If lsm is not NULL only look at
+ * that module.
+ *
+ * "context" is handled directly here.
+ */
+ if (strcmp(name, "context") == 0) {
+ /*
+ * First verify that the input is acceptable.
+ * lsm1='v1'lsm2='v2'lsm3='v3'
+ *
+ * A note on the use of strncmp() below.
+ * The check is for the substring at the beginning of cp.
+ * The kzalloc of size + 1 ensures a terminated string.
+ */
+ local = kzalloc(size + 1, GFP_KERNEL);
+ memcpy(local, value, size);
+ cp = local;
+ list_for_each_entry(hp, &security_hook_heads.setprocattr,
+ list) {
+ if (lsm != NULL && strcmp(lsm, hp->lsm))
+ continue;
+ if (cp[0] == ',') {
+ if (cp == local)
+ goto free_out;
+ cp++;
+ }
+ slen = strlen(hp->lsm);
+ if (strncmp(cp, hp->lsm, slen))
+ goto free_out;
+ cp += slen;
+ if (cp[0] != '=' || cp[1] != '\'' || cp[2] == '\'')
+ goto free_out;
+ for (cp += 2; cp[0] != '\''; cp++)
+ if (cp[0] == '\0')
+ goto free_out;
+ cp++;
+ }
+ cp = local;
+ list_for_each_entry(hp, &security_hook_heads.setprocattr,
+ list) {
+ if (lsm != NULL && strcmp(lsm, hp->lsm))
+ continue;
+ if (cp[0] == ',')
+ cp++;
+ cp += strlen(hp->lsm) + 2;
+ for (slen = 0; cp[slen] != '\''; slen++)
+ ;
+ cp[slen] = '\0';
+
+ rc = hp->hook.setprocattr(p, "context", cp, slen);
+ if (rc < 0)
+ failed = rc;
+ cp += slen + 1;
+ }
+ if (failed != 0)
+ rc = failed;
+ else
+ rc = size;
+free_out:
+ kfree(local);
+ return rc;
+ }
list_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
if (lsm != NULL && strcmp(lsm, hp->lsm))
continue;
@@ -5711,6 +5711,8 @@ static int selinux_getprocattr(struct task_struct *p,
if (!strcmp(name, "current"))
sid = __tsec->sid;
+ else if (!strcmp(name, "context"))
+ sid = __tsec->sid;
else if (!strcmp(name, "prev"))
sid = __tsec->osid;
else if (!strcmp(name, "exec"))
@@ -5728,7 +5730,19 @@ static int selinux_getprocattr(struct task_struct *p,
if (!sid)
return 0;
- error = security_sid_to_context(sid, value, &len);
+ if (strcmp(name, "context")) {
+ error = security_sid_to_context(sid, value, &len);
+ } else {
+ char *vp;
+
+ error = security_sid_to_context(sid, &vp, &len);
+ if (!error) {
+ *value = kasprintf(GFP_KERNEL, "selinux='%s'", vp);
+ if (*value == NULL)
+ error = -ENOMEM;
+ }
+ }
+
if (error)
return error;
return len;
@@ -5768,6 +5782,8 @@ static int selinux_setprocattr(struct task_struct *p,
error = current_has_perm(p, PROCESS__SETSOCKCREATE);
else if (!strcmp(name, "current"))
error = current_has_perm(p, PROCESS__SETCURRENT);
+ else if (!strcmp(name, "context"))
+ error = current_has_perm(p, PROCESS__SETCURRENT);
else
error = -EINVAL;
if (error)
@@ -5827,7 +5843,7 @@ static int selinux_setprocattr(struct task_struct *p,
tsec->keycreate_sid = sid;
} else if (!strcmp(name, "sockcreate")) {
tsec->sockcreate_sid = sid;
- } else if (!strcmp(name, "current")) {
+ } else if (!strcmp(name, "current") || !strcmp(name, "context")) {
error = -EINVAL;
if (sid == 0)
goto abort_change;
@@ -3574,18 +3574,20 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
{
struct smack_known *skp = smk_of_task_struct(p);
char *cp;
- int slen;
- if (strcmp(name, "current") != 0)
+ if (strcmp(name, "current") == 0) {
+ cp = kstrdup(skp->smk_known, GFP_KERNEL);
+ if (cp == NULL)
+ return -ENOMEM;
+ } else if (strcmp(name, "context") == 0) {
+ cp = kasprintf(GFP_KERNEL, "smack='%s'", skp->smk_known);
+ if (cp == NULL)
+ return -ENOMEM;
+ } else
return -EINVAL;
- cp = kstrdup(skp->smk_known, GFP_KERNEL);
- if (cp == NULL)
- return -ENOMEM;
-
- slen = strlen(cp);
*value = cp;
- return slen;
+ return strlen(cp);
}
/**
@@ -3622,7 +3624,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
return -EINVAL;
- if (strcmp(name, "current") != 0)
+ if (strcmp(name, "current") != 0 && strcmp(name, "context") != 0)
return -EINVAL;
skp = smk_import_entry(value, size);
Subject: [PATCH v5 3/3] LSM: Add context interface for proc attrs The /proc/.../attr/current interface is used by all three Linux security modules (SELinux, Smack and AppArmor) to report and modify the process security attribute. This is all fine when there is exactly one of these modules active and the userspace code knows which it module it is. It would require a major change to the "current" interface to provide information about more than one set of process security attributes. Instead, a "context" attribute is added, which identifies the security module that the information applies to. The format is: lsmname='context-value' When multiple concurrent modules are supported the /proc/.../attr/context interface will include the data for all of the active modules. lsmname1='context-value1',lsmname2='context-value2' The module specific subdirectories under attr contain context entries that report the information for that specific module in the same format. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: Paul Moore <paul@paul-moore.com> Acked-by: Kees Cook <keescook@chromium.org> --- Documentation/security/LSM.txt | 8 +++ fs/proc/base.c | 4 ++ security/apparmor/lsm.c | 35 +++++++++++-- security/security.c | 108 +++++++++++++++++++++++++++++++++++++++++ security/selinux/hooks.c | 20 +++++++- security/smack/smack_lsm.c | 20 ++++---- 6 files changed, 180 insertions(+), 15 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html