Re: [PATCH v3 2/2] sysctl: treewide: constify argument ctl_table_root::permissions(table)
From: Joel Granados <hidden>
Date: 2024-03-22 12:32:57
Also in:
linux-fsdevel, lkml
On Fri, Mar 15, 2024 at 07:11:31PM +0100, Thomas Weißschuh wrote:
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:
@@
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)
The three changed locations were validated through manually inspection
and compilation.Will remove this when I add it to constfy branch as it is unclear (for me) what "manually inspection" is and also I do not know what config you used to compile. IMO, we can just do without it.
In addition a search for '.permissions =' was done over the full tree to look for places that were missed by coccinelle. None were found. This change also is a step to put "struct ctl_table" into .rodata throughout the kernel.
This LGTM. Will add this to the constfy testing branch with these
changes in the commit message:
"""
sysctl: treewide: constify argument ctl_table_root::permissions(table)
The permissions callback should not modify the ctl_table. Enforce this
expectation via the typesystem. This is a step to put "struct ctl_table"
into .rodata throughout the kernel.
The patch was created with the following coccinelle script:
@@
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)
No additional occurances of '.permissions =' were found after a
tree-wide search for places missed by the conccinelle script.
"""
Reviewed-by: Joel Granados <redacted>quoted hunk ↗ jump to hunk
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> --- include/linux/sysctl.h | 2 +- ipc/ipc_sysctl.c | 2 +- ipc/mq_sysctl.c | 2 +- kernel/ucount.c | 2 +- net/sysctl_net.c | 2 +- 5 files changed, 5 insertions(+), 5 deletions(-)diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 60333a6b9370..f9214de0490c 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h@@ -206,7 +206,7 @@ struct ctl_table_root { struct ctl_table_set *(*lookup)(struct ctl_table_root *root); void (*set_ownership)(struct ctl_table_header *head, 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); }; #define register_sysctl(path, table) \diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c index 1a5085e5b178..19b2a67aef40 100644 --- a/ipc/ipc_sysctl.c +++ b/ipc/ipc_sysctl.c@@ -204,7 +204,7 @@ static void ipc_set_ownership(struct ctl_table_header *head, *gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID; } -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/ipc/mq_sysctl.c b/ipc/mq_sysctl.c index 6bb1c5397c69..43c0825da9e8 100644 --- a/ipc/mq_sysctl.c +++ b/ipc/mq_sysctl.c@@ -90,7 +90,7 @@ static void mq_set_ownership(struct ctl_table_header *head, *gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID; } -static int mq_permissions(struct ctl_table_header *head, struct ctl_table *table) +static int mq_permissions(struct ctl_table_header *head, const struct ctl_table *table) { int mode = table->mode; kuid_t ns_root_uid;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 a0a7a79991f9..f5017012a049 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);-- 2.44.0
-- Joel Granados
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