[RFC PATCH 22/39] sysctl: refresh namespace IPC bounds per call

[wen.yang@linux.dev]

From: Wen Yang <wen.yang@linux.dev>

Refresh IPC limits before validating namespace sysctl writes.

Suggested-by: Joel Granados <joel.granados@kernel.org>
Signed-off-by: Wen Yang <wen.yang@linux.dev>
---
 ipc/ipc_sysctl.c | 50 ++++++++++++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 21 deletions(-)

diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index e02e2ea70907..29a1f442c503 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -6,7 +6,6 @@
  */
 
 #include <linux/module.h>
-#include <linux/limits.h>
 #include <linux/ipc.h>
 #include <linux/nsproxy.h>
 #include <linux/sysctl.h>
@@ -74,6 +73,15 @@ int ipc_mni = IPCMNI;
 int ipc_mni_shift = IPCMNI_SHIFT;
 int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
 
+static int proc_ipc_mni(const struct ctl_table *table, int write,
+			void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table tmp = *table;
+
+	tmp.max = READ_ONCE(ipc_mni);
+	return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+}
+
 static const struct ctl_table ipc_sysctls[] = {
 	{
 		.procname	= "shmmax",
@@ -98,9 +106,9 @@ static const struct ctl_table ipc_sysctls[] = {
 		.data		= &init_ipc_ns.shm_ctlmni,
 		.maxlen		= sizeof(init_ipc_ns.shm_ctlmni),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &ipc_mni,
+		.proc_handler	= proc_ipc_mni,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "shm_rmid_forced",
@@ -108,8 +116,8 @@ static const struct ctl_table ipc_sysctls[] = {
 		.maxlen		= sizeof(init_ipc_ns.shm_rmid_forced),
 		.mode		= 0644,
 		.proc_handler	= proc_ipc_dointvec_minmax_orphans,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
+		.min		= 0,
+		.max		= 1,
 	},
 	{
 		.procname	= "msgmax",
@@ -117,17 +125,17 @@ static const struct ctl_table ipc_sysctls[] = {
 		.maxlen		= sizeof(init_ipc_ns.msg_ctlmax),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "msgmni",
 		.data		= &init_ipc_ns.msg_ctlmni,
 		.maxlen		= sizeof(init_ipc_ns.msg_ctlmni),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &ipc_mni,
+		.proc_handler	= proc_ipc_mni,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "auto_msgmni",
@@ -135,8 +143,8 @@ static const struct ctl_table ipc_sysctls[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_ipc_auto_msgmni,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
+		.min		= 0,
+		.max		= 1,
 	},
 	{
 		.procname	=  "msgmnb",
@@ -144,8 +152,8 @@ static const struct ctl_table ipc_sysctls[] = {
 		.maxlen		= sizeof(init_ipc_ns.msg_ctlmnb),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "sem",
@@ -161,8 +169,8 @@ static const struct ctl_table ipc_sysctls[] = {
 		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "msg_next_id",
@@ -170,8 +178,8 @@ static const struct ctl_table ipc_sysctls[] = {
 		.maxlen		= sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 	{
 		.procname	= "shm_next_id",
@@ -179,8 +187,8 @@ static const struct ctl_table ipc_sysctls[] = {
 		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_INT_MAX,
+		.min		= 0,
+		.max		= INT_MAX,
 	},
 #endif
 };
-- 
2.25.1