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Message-Id: <20231226-sysctl-const-permissions-v1-1-5cd3c91f6299@weissschuh.net>
Date: Tue, 26 Dec 2023 13:08:48 +0100
From: Thomas Weißschuh <linux@...ssschuh.net>
To: Luis Chamberlain <mcgrof@...nel.org>, Kees Cook <keescook@...omium.org>,
Joel Granados <j.granados@...sung.com>,
"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
netdev@...r.kernel.org,
Thomas Weißschuh <linux@...ssschuh.net>
Subject: [PATCH] sysctl: treewide: constify ctl_table_root::permissions
The permissions callback is not supposed to modify the ctl_table.
Enforce this expectation via the typesystem.
The patch was created with the following coccinelle script:
virtual patch
virtual context
virtual report
@@
identifier func, head, ctl;
@@
int func(
struct ctl_table_header *head,
- struct ctl_table *ctl)
+ const struct ctl_table *ctl)
{ ... }
(insert_entry() from fs/proc/proc_sysctl.c is a false-positive)
This change also is a step to put "struct ctl_table" into .rodata
throughout the kernel.
Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
---
The patch is meant to be merged via the sysctl tree.
This change was originally part of the sysctl-const series [0].
To slim down that series and reduce the message load on other
maintainers to a minimumble, submit this patch on its own.
[0] https://lore.kernel.org/lkml/20231204-const-sysctl-v2-2-7a5060b11447@weissschuh.net/
---
include/linux/sysctl.h | 2 +-
ipc/ipc_sysctl.c | 2 +-
kernel/ucount.c | 2 +-
net/sysctl_net.c | 2 +-
4 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 26a38161c28f..8ec2d742c3b4 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -207,7 +207,7 @@ struct ctl_table_root {
void (*set_ownership)(struct ctl_table_header *head,
struct ctl_table *table,
kuid_t *uid, kgid_t *gid);
- int (*permissions)(struct ctl_table_header *head, struct ctl_table *table);
+ int (*permissions)(struct ctl_table_header *head, const struct ctl_table *table);
};
/* struct ctl_path describes where in the hierarchy a table is added */
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index 8c62e443f78b..b087787f608f 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -190,7 +190,7 @@ static int set_is_seen(struct ctl_table_set *set)
return ¤t->nsproxy->ipc_ns->ipc_set == set;
}
-static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table)
+static int ipc_permissions(struct ctl_table_header *head, const struct ctl_table *table)
{
int mode = table->mode;
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 4aa6166cb856..90300840256b 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -38,7 +38,7 @@ static int set_is_seen(struct ctl_table_set *set)
}
static int set_permissions(struct ctl_table_header *head,
- struct ctl_table *table)
+ const struct ctl_table *table)
{
struct user_namespace *user_ns =
container_of(head->set, struct user_namespace, set);
diff --git a/net/sysctl_net.c b/net/sysctl_net.c
index 051ed5f6fc93..ba9a49de9600 100644
--- a/net/sysctl_net.c
+++ b/net/sysctl_net.c
@@ -40,7 +40,7 @@ static int is_seen(struct ctl_table_set *set)
/* Return standard mode bits for table entry. */
static int net_ctl_permissions(struct ctl_table_header *head,
- struct ctl_table *table)
+ const struct ctl_table *table)
{
struct net *net = container_of(head->set, struct net, sysctls);
---
base-commit: de2ee5e9405e12600c81e39837362800cee433a2
change-id: 20231226-sysctl-const-permissions-d7cfd02a7637
Best regards,
--
Thomas Weißschuh <linux@...ssschuh.net>
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