Thread (21 messages) 21 messages, 3 authors, 2017-06-29

[RFC v2 8/9] Allowing for stacking procattr support in S.A.R.A.

From: Salvatore Mesoraca <hidden>
Date: 2017-06-15 16:44:47
Also in: linux-mm, lkml
Subsystem: filesystems (vfs and infrastructure), proc filesystem, security subsystem, the rest · Maintainers: Alexander Viro, Christian Brauner, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds

This allow S.A.R.A. to use the procattr interface without interfering
with other LSMs.
This part should be reimplemented as soon as upstream procattr stacking
support is available.

Signed-off-by: Salvatore Mesoraca <redacted>
---
 fs/proc/base.c      | 38 ++++++++++++++++++++++++++++++++++++++
 security/security.c | 20 ++++++++++++++++++--
 2 files changed, 56 insertions(+), 2 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index f1e1927..6d0fd1c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2515,6 +2515,40 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
 	.llseek		= generic_file_llseek,
 };
 
+#ifdef CONFIG_SECURITY_SARA
+static const struct pid_entry sara_attr_dir_stuff[] = {
+	REG("wxprot", 0666, proc_pid_attr_operations),
+};
+
+static int proc_sara_attr_dir_readdir(struct file *file,
+				      struct dir_context *ctx)
+{
+	return proc_pident_readdir(file, ctx,
+				   sara_attr_dir_stuff,
+				   ARRAY_SIZE(sara_attr_dir_stuff));
+}
+
+static const struct file_operations proc_sara_attr_dir_ops = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_sara_attr_dir_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+static struct dentry *proc_sara_attr_dir_lookup(struct inode *dir,
+				struct dentry *dentry, unsigned int flags)
+{
+	return proc_pident_lookup(dir, dentry,
+				  sara_attr_dir_stuff,
+				  ARRAY_SIZE(sara_attr_dir_stuff));
+};
+
+static const struct inode_operations proc_sara_attr_dir_inode_ops = {
+	.lookup		= proc_sara_attr_dir_lookup,
+	.getattr	= pid_getattr,
+	.setattr	= proc_setattr,
+};
+#endif /* CONFIG_SECURITY_SARA */
+
 static const struct pid_entry attr_dir_stuff[] = {
 	REG("current",    S_IRUGO|S_IWUGO, proc_pid_attr_operations),
 	REG("prev",       S_IRUGO,	   proc_pid_attr_operations),
@@ -2522,6 +2556,10 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
 	REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
 	REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
 	REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
+#ifdef CONFIG_SECURITY_SARA
+	DIR("sara", 0555, proc_sara_attr_dir_inode_ops,
+				proc_sara_attr_dir_ops),
+#endif
 };
 
 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
diff --git a/security/security.c b/security/security.c
index f7df697..c6c78dd 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1239,12 +1239,28 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
 
 int security_getprocattr(struct task_struct *p, char *name, char **value)
 {
-	return call_int_hook(getprocattr, -EINVAL, p, name, value);
+	struct security_hook_list *hp;
+	int rc;
+
+	list_for_each_entry(hp, &security_hook_heads.getprocattr, list) {
+		rc = hp->hook.getprocattr(p, name, value);
+		if (rc != -EINVAL)
+			return rc;
+	}
+	return -EINVAL;
 }
 
 int security_setprocattr(const char *name, void *value, size_t size)
 {
-	return call_int_hook(setprocattr, -EINVAL, name, value, size);
+	struct security_hook_list *hp;
+	int rc;
+
+	list_for_each_entry(hp, &security_hook_heads.setprocattr, list) {
+		rc = hp->hook.setprocattr(name, value, size);
+		if (rc != -EINVAL)
+			return rc;
+	}
+	return -EINVAL;
 }
 
 int security_netlink_send(struct sock *sk, struct sk_buff *skb)
-- 
1.9.1

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