LSM: SafeSetID: refactor policy parsing (78ae7df9) · Commits · 戴 / test

security/safesetid/securityfs.c

+33 −51

Original line number	Diff line number	Diff line
		@@ -33,68 +33,50 @@ static struct safesetid_file_entry safesetid_files[] = {

		/*
		* In the case the input buffer contains one or more invalid UIDs, the kuid_t
		* variables pointed to by 'parent' and 'child' will get updated but this
		* variables pointed to by @parent and @child will get updated but this
		* function will return an error.
		* Contents of @buf may be modified.
		*/
		static int parse_safesetid_whitelist_policy(const char __user *buf,
		size_t len,
		kuid_t *parent,
		kuid_t *child)
		static int parse_policy_line(
		struct file file, char buf, kuid_t parent, kuid_t child)
		{
		char *kern_buf;
		char *parent_buf;
		char *child_buf;
		const char separator[] = ":";
		char *child_str;
		int ret;
		size_t first_substring_length;
		long parsed_parent;
		long parsed_child;

		/* Duplicate string from user memory and NULL-terminate */
		kern_buf = memdup_user_nul(buf, len);
		if (IS_ERR(kern_buf))
		return PTR_ERR(kern_buf);
		u32 parsed_parent, parsed_child;

		/*
		* Format of \|buf\| string should be <UID>:<UID>.
		* Find location of ":" in kern_buf (copied from \|buf\|).
		*/
		first_substring_length = strcspn(kern_buf, separator);
		if (first_substring_length == 0 \|\| first_substring_length == len) {
		ret = -EINVAL;
		goto free_kern;
		}

		parent_buf = kmemdup_nul(kern_buf, first_substring_length, GFP_KERNEL);
		if (!parent_buf) {
		ret = -ENOMEM;
		goto free_kern;
		}
		/* Format of \|buf\| string should be <UID>:<UID>. */
		child_str = strchr(buf, ':');
		if (child_str == NULL)
		return -EINVAL;
		*child_str = '\0';
		child_str++;

		ret = kstrtol(parent_buf, 0, &parsed_parent);
		ret = kstrtou32(buf, 0, &parsed_parent);
		if (ret)
		goto free_both;
		return ret;

		child_buf = kern_buf + first_substring_length + 1;
		ret = kstrtol(child_buf, 0, &parsed_child);
		ret = kstrtou32(child_str, 0, &parsed_child);
		if (ret)
		goto free_both;
		return ret;

		*parent = make_kuid(current_user_ns(), parsed_parent);
		if (!uid_valid(*parent)) {
		ret = -EINVAL;
		goto free_both;
		}

		*child = make_kuid(current_user_ns(), parsed_child);
		if (!uid_valid(*child)) {
		ret = -EINVAL;
		goto free_both;
		if (!uid_valid(parent) \|\| !uid_valid(child))
		return -EINVAL;

		return 0;
		}

		free_both:
		kfree(parent_buf);
		free_kern:
		static int parse_safesetid_whitelist_policy(
		struct file file, const char __user buf, size_t len,
		kuid_t parent, kuid_t child)
		{
		char *kern_buf = memdup_user_nul(buf, len);
		int ret;

		if (IS_ERR(kern_buf))
		return PTR_ERR(kern_buf);
		ret = parse_policy_line(file, kern_buf, parent, child);
		kfree(kern_buf);
		return ret;
		}
		@@ -121,8 +103,8 @@ static ssize_t safesetid_file_write(struct file *file,
		flush_safesetid_whitelist_entries();
		break;
		case SAFESETID_WHITELIST_ADD:
		ret = parse_safesetid_whitelist_policy(buf, len, &parent,
		&child);
		ret = parse_safesetid_whitelist_policy(file, buf, len,
		&parent, &child);
		if (ret)
		return ret;

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