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From:   Joel Granados <j.granados@samsung.com>
To:     mcgrof@kernel.org, Kees Cook <keescook@chromium.org>,
        Iurii Zaikin <yzaikin@google.com>
Cc:     willy@infradead.org, josh@joshtriplett.org,
        Joel Granados <j.granados@samsung.com>,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH 01/14] sysctl: Prefer ctl_table_header in proc_sysctl
Date:   Wed, 26 Jul 2023 16:06:21 +0200
Message-Id: <20230726140635.2059334-2-j.granados@samsung.com>
In-Reply-To: <20230726140635.2059334-1-j.granados@samsung.com>
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References: <20230726140635.2059334-1-j.granados@samsung.com>
        <CGME20230726140650eucas1p1f5b2aa9dd8f90989c881f0a2e682b9eb@eucas1p1.samsung.com>
Precedence: bulk

This is a preparation commit to use ctl_table_header instead of
ctl_table as the element that is passed around in proc_sysctl.c.
This will become necessary when the size can no longer be calculated
by searching for an empty sentinel in the ctl_table array and
will live in the ctl_table_header.

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 fs/proc/proc_sysctl.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 5ea42653126e..94d71446da39 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1125,11 +1125,11 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
 	return err;
 }
 
-static int sysctl_check_table(const char *path, struct ctl_table *table)
+static int sysctl_check_table(const char *path, struct ctl_table_header *header)
 {
 	struct ctl_table *entry;
 	int err = 0;
-	list_for_each_table_entry(entry, table) {
+	list_for_each_table_entry(entry, header->ctl_table) {
 		if ((entry->proc_handler == proc_dostring) ||
 		    (entry->proc_handler == proc_dobool) ||
 		    (entry->proc_handler == proc_dointvec) ||
@@ -1159,8 +1159,7 @@ static int sysctl_check_table(const char *path, struct ctl_table *table)
 	return err;
 }
 
-static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
-	struct ctl_table_root *link_root)
+static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_header *head)
 {
 	struct ctl_table *link_table, *entry, *link;
 	struct ctl_table_header *links;
@@ -1170,7 +1169,7 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table
 
 	name_bytes = 0;
 	nr_entries = 0;
-	list_for_each_table_entry(entry, table) {
+	list_for_each_table_entry(entry, head->ctl_table) {
 		nr_entries++;
 		name_bytes += strlen(entry->procname) + 1;
 	}
@@ -1189,12 +1188,12 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table
 	link_name = (char *)&link_table[nr_entries + 1];
 	link = link_table;
 
-	list_for_each_table_entry(entry, table) {
+	list_for_each_table_entry(entry, head->ctl_table) {
 		int len = strlen(entry->procname) + 1;
 		memcpy(link_name, entry->procname, len);
 		link->procname = link_name;
 		link->mode = S_IFLNK|S_IRWXUGO;
-		link->data = link_root;
+		link->data = head->root;
 		link_name += len;
 		link++;
 	}
@@ -1205,15 +1204,16 @@ static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table
 }
 
 static bool get_links(struct ctl_dir *dir,
-	struct ctl_table *table, struct ctl_table_root *link_root)
+		      struct ctl_table_header *header,
+		      struct ctl_table_root *link_root)
 {
-	struct ctl_table_header *head;
+	struct ctl_table_header *tmp_head;
 	struct ctl_table *entry, *link;
 
 	/* Are there links available for every entry in table? */
-	list_for_each_table_entry(entry, table) {
+	list_for_each_table_entry(entry, header->ctl_table) {
 		const char *procname = entry->procname;
-		link = find_entry(&head, dir, procname, strlen(procname));
+		link = find_entry(&tmp_head, dir, procname, strlen(procname));
 		if (!link)
 			return false;
 		if (S_ISDIR(link->mode) && S_ISDIR(entry->mode))
@@ -1224,10 +1224,10 @@ static bool get_links(struct ctl_dir *dir,
 	}
 
 	/* The checks passed.  Increase the registration count on the links */
-	list_for_each_table_entry(entry, table) {
+	list_for_each_table_entry(entry, header->ctl_table) {
 		const char *procname = entry->procname;
-		link = find_entry(&head, dir, procname, strlen(procname));
-		head->nreg++;
+		link = find_entry(&tmp_head, dir, procname, strlen(procname));
+		tmp_head->nreg++;
 	}
 	return true;
 }
@@ -1246,13 +1246,13 @@ static int insert_links(struct ctl_table_header *head)
 	if (IS_ERR(core_parent))
 		return 0;
 
-	if (get_links(core_parent, head->ctl_table, head->root))
+	if (get_links(core_parent, head, head->root))
 		return 0;
 
 	core_parent->header.nreg++;
 	spin_unlock(&sysctl_lock);
 
-	links = new_links(core_parent, head->ctl_table, head->root);
+	links = new_links(core_parent, head);
 
 	spin_lock(&sysctl_lock);
 	err = -ENOMEM;
@@ -1260,7 +1260,7 @@ static int insert_links(struct ctl_table_header *head)
 		goto out;
 
 	err = 0;
-	if (get_links(core_parent, head->ctl_table, head->root)) {
+	if (get_links(core_parent, head, head->root)) {
 		kfree(links);
 		goto out;
 	}
@@ -1371,7 +1371,7 @@ struct ctl_table_header *__register_sysctl_table(
 
 	node = (struct ctl_node *)(header + 1);
 	init_header(header, root, set, node, table);
-	if (sysctl_check_table(path, table))
+	if (sysctl_check_table(path, header))
 		goto fail;
 
 	spin_lock(&sysctl_lock);
-- 
2.30.2