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Groups > linux.kernel > #1437146
| From | Casey Schaufler <casey@schaufler-ca.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v5 3/3] LSM: Add context interface for proc attrs - Acked |
| Date | 2016-07-05 18:00 +0200 |
| Message-ID | <rRAVt-4Ms-35@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <rNFTI-4ti-23@gated-at.bofh.it> <rNIHT-6dD-5@gated-at.bofh.it> <rNIRz-6gS-7@gated-at.bofh.it> <rPr9U-6Wn-3@gated-at.bofh.it> <rQwTU-6l3-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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(-)
diff --git a/Documentation/security/LSM.txt b/Documentation/security/LSM.txt
index 125c489..af3eb11 100644
--- a/Documentation/security/LSM.txt
+++ b/Documentation/security/LSM.txt
@@ -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
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 182bc28..df94f26 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -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),
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index fb0fb03..5cac15f 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -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)
diff --git a/security/security.c b/security/security.c
index 1e9cb55..f97f0d9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -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;
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ed3a757..6397721 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -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;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 3577009..92e66f8 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -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);
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH v4 0/3] LSM: module hierarchy in /proc/.../attr Casey Schaufler <casey@schaufler-ca.com> - 2016-06-23 23:10 +0200
[PATCH v4 1/3] LSM: Add /sys/kernel/security/lsm Casey Schaufler <casey@schaufler-ca.com> - 2016-06-23 23:20 +0200
Re: [PATCH v4 1/3] LSM: Add /sys/kernel/security/lsm Paul Moore <paul@paul-moore.com> - 2016-06-24 21:00 +0200
[PATCH v4 2/3] LSM: module hierarchy in /proc/.../attr Casey Schaufler <casey@schaufler-ca.com> - 2016-06-23 23:20 +0200
Re: [PATCH v4 2/3] LSM: module hierarchy in /proc/.../attr Paul Moore <paul@paul-moore.com> - 2016-06-24 21:20 +0200
Re: [PATCH v4 2/3] LSM: module hierarchy in /proc/.../attr Kees Cook <keescook@chromium.org> - 2016-06-24 22:10 +0200
Re: [PATCH v4 2/3] LSM: module hierarchy in /proc/.../attr Paul Moore <paul@paul-moore.com> - 2016-06-24 22:30 +0200
[PATCH v5 2/3] LSM: module hierarchy in /proc/.../attr Casey Schaufler <casey@schaufler-ca.com> - 2016-06-25 01:30 +0200
Re: [PATCH v5 2/3] LSM: module hierarchy in /proc/.../attr Paul Moore <paul@paul-moore.com> - 2016-06-29 19:10 +0200
Re: [PATCH v5 2/3] LSM: module hierarchy in /proc/.../attr John Johansen <john.johansen@canonical.com> - 2016-07-02 19:30 +0200
[PATCH v5 1/3] LSM: Add /sys/kernel/security/lsm Casey Schaufler <casey@schaufler-ca.com> - 2016-06-25 01:30 +0200
Re: [PATCH v5 1/3] LSM: Add /sys/kernel/security/lsm Paul Moore <paul@paul-moore.com> - 2016-06-29 19:10 +0200
Re: [PATCH v5 1/3] LSM: Add /sys/kernel/security/lsm John Johansen <john.johansen@canonical.com> - 2016-07-02 19:30 +0200
[PATCH v5 0/3] LSM: security module information improvements Casey Schaufler <casey@schaufler-ca.com> - 2016-06-25 01:30 +0200
[PATCH v5 3/3] LSM: Add context interface for proc attrs Casey Schaufler <casey@schaufler-ca.com> - 2016-06-25 01:40 +0200
[PATCH v4 3/3] LSM: Add context interface for proc attrs Casey Schaufler <casey@schaufler-ca.com> - 2016-06-25 01:40 +0200
Re: [PATCH v4 3/3] LSM: Add context interface for proc attrs Paul Moore <paul@paul-moore.com> - 2016-06-29 19:10 +0200
Re: [PATCH v4 3/3] LSM: Add context interface for proc attrs John Johansen <john.johansen@canonical.com> - 2016-07-02 19:30 +0200
[PATCH v5 0/3] LSM: security module information improvements - Acked Casey Schaufler <casey@schaufler-ca.com> - 2016-07-05 18:00 +0200
Re: [PATCH v5 0/3] LSM: security module information improvements - Acked James Morris <jmorris@namei.org> - 2016-07-08 12:10 +0200
Re: [PATCH v5 0/3] LSM: security module information improvements - Acked Casey Schaufler <casey@schaufler-ca.com> - 2016-07-08 17:40 +0200
[PATCH v5 2/3] LSM: module hierarchy in /proc/.../attr - Acked Casey Schaufler <casey@schaufler-ca.com> - 2016-07-05 18:00 +0200
[PATCH v5 1/3] LSM: Add /sys/kernel/security/lsm - Acked Casey Schaufler <casey@schaufler-ca.com> - 2016-07-05 18:00 +0200
[PATCH v5 3/3] LSM: Add context interface for proc attrs - Acked Casey Schaufler <casey@schaufler-ca.com> - 2016-07-05 18:00 +0200
Re: [PATCH v4 2/3] LSM: module hierarchy in /proc/.../attr Casey Schaufler <casey@schaufler-ca.com> - 2016-06-24 22:10 +0200
[PATCH v4 3/3] LSM: Add context interface for proc attrs Casey Schaufler <casey@schaufler-ca.com> - 2016-06-23 23:20 +0200
Re: [PATCH v4 3/3] LSM: Add context interface for proc attrs Kees Cook <keescook@chromium.org> - 2016-06-24 00:00 +0200
Re: [PATCH v4 3/3] LSM: Add context interface for proc attrs Casey Schaufler <casey@schaufler-ca.com> - 2016-06-24 00:20 +0200
[PATCH v4 4/3] LSM: Improve context interface for proc attrs Casey Schaufler <casey@schaufler-ca.com> - 2016-06-24 18:40 +0200
Re: [PATCH v4 4/3] LSM: Improve context interface for proc attrs Kees Cook <keescook@chromium.org> - 2016-06-24 19:50 +0200
Re: [PATCH v4 3/3] LSM: Add context interface for proc attrs Paul Moore <paul@paul-moore.com> - 2016-06-24 21:20 +0200
Re: [PATCH v4 3/3] LSM: Add context interface for proc attrs Casey Schaufler <casey@schaufler-ca.com> - 2016-06-24 22:00 +0200
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