[PATCH v4 03/11] lsm: add file opener's cred to a setprocattr arguments

From: Lukasz Pawelczyk
Date: Wed Oct 14 2015 - 08:59:10 EST


setprocattr hook for Smack's label_map attribute needs to know the
capabilities of file opener. Add those credentials to the hook's
arguments.

While at it add documentation on get/setprocattr hooks.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@xxxxxxxxxxx>
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
---
fs/proc/base.c | 2 +-
include/linux/lsm_hooks.h | 18 ++++++++++++++++--
include/linux/security.h | 7 +++++--
security/apparmor/lsm.c | 5 +++--
security/security.c | 6 ++++--
security/selinux/hooks.c | 2 +-
security/smack/smack_lsm.c | 4 ++--
7 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9ec88b8..2b38969 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2447,7 +2447,7 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
if (length < 0)
goto out_free;

- length = security_setprocattr(task,
+ length = security_setprocattr(task, file->f_cred,
(char*)file->f_path.dentry->d_name.name,
(void*)page, count);
mutex_unlock(&task->signal->cred_guard_mutex);
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 7049db0..4f16640 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1220,6 +1220,20 @@
* Return 0 if @name is to be handled by seq, EOPNOTSUPP if getprocattr()
* should be used. Other errors will be passed to user-space.
*
+ * @getprocattr:
+ * Get a value of a proc security attribute in /proc/$PID/attr/.
+ * @p a task associated with the proc file.
+ * @name a name of the file in question.
+ * @value a pointer where to return the attribute's value.
+ *
+ * @setprocattr:
+ * Set a value of a proc security attribute in /proc/$PID/attr/.
+ * @p a task associated with the proc file.
+ * @f_cred credentials of a file's opener.
+ * @name a name of the file in question.
+ * @value a pointer where a value to set is kept.
+ * @size a number of bytes to read from the @value pointer.
+ *
* @secid_to_secctx:
* Convert secid to security context. If secdata is NULL the length of
* the result will be returned in seclen, but no secdata will be returned.
@@ -1540,8 +1554,8 @@ union security_list_options {
int (*getprocattr_seq)(struct task_struct *p, const char *name,
const struct seq_operations **ops);
int (*getprocattr)(struct task_struct *p, char *name, char **value);
- int (*setprocattr)(struct task_struct *p, char *name, void *value,
- size_t size);
+ int (*setprocattr)(struct task_struct *p, const struct cred *f_cred,
+ char *name, void *value, size_t size);
int (*ismaclabel)(const char *name);
int (*secid_to_secctx)(u32 secid, char **secdata, u32 *seclen);
int (*secctx_to_secid)(const char *secdata, u32 seclen, u32 *secid);
diff --git a/include/linux/security.h b/include/linux/security.h
index dddea2f..12bd011 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -348,7 +348,8 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode);
int security_getprocattr_seq(struct task_struct *p, const char *name,
const struct seq_operations **ops);
int security_getprocattr(struct task_struct *p, char *name, char **value);
-int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
+int security_setprocattr(struct task_struct *p, const struct cred *f_cred,
+ char *name, void *value, size_t size);
int security_netlink_send(struct sock *sk, struct sk_buff *skb);
int security_ismaclabel(const char *name);
int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
@@ -1071,7 +1072,9 @@ static inline int security_getprocattr(struct task_struct *p, char *name, char *
return -EINVAL;
}

-static inline int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
+static inline int security_setprocattr(struct task_struct *p,
+ const struct cred *f_cred,
+ char *name, void *value, size_t size)
{
return -EINVAL;
}
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index dec607c..1212927 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -518,8 +518,9 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
return error;
}

-static int apparmor_setprocattr(struct task_struct *task, char *name,
- void *value, size_t size)
+static int apparmor_setprocattr(struct task_struct *task,
+ const struct cred *f_cred,
+ char *name, void *value, size_t size)
{
struct common_audit_data sa;
struct apparmor_audit_data aad = {0,};
diff --git a/security/security.c b/security/security.c
index da2bcd4..abfc207 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1132,9 +1132,11 @@ int security_getprocattr(struct task_struct *p, char *name, char **value)
return call_int_hook(getprocattr, -EINVAL, p, name, value);
}

-int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
+int security_setprocattr(struct task_struct *p, const struct cred *f_cred,
+ char *name, void *value, size_t size)
{
- return call_int_hook(setprocattr, -EINVAL, p, name, value, size);
+ return call_int_hook(setprocattr, -EINVAL, p, f_cred,
+ name, value, size);
}

int security_netlink_send(struct sock *sk, struct sk_buff *skb)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e4369d8..470eff8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5603,7 +5603,7 @@ invalid:
return -EINVAL;
}

-static int selinux_setprocattr(struct task_struct *p,
+static int selinux_setprocattr(struct task_struct *p, const struct cred *f_cred,
char *name, void *value, size_t size)
{
struct task_security_struct *tsec;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index c2d66ca..c439370 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3549,8 +3549,8 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
*
* Returns the length of the smack label or an error code
*/
-static int smack_setprocattr(struct task_struct *p, char *name,
- void *value, size_t size)
+static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
+ char *name, void *value, size_t size)
{
struct task_smack *tsp;
struct cred *new;
--
2.4.3

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