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Subject[PATCH 2/4] sysctl: Implement sysctl_uts_string
Date
The problem:  When using sys_sysctl we don't read the proper values
for the variables exported from the uts namespace, nor do we do the
proper locking.

This patch introduces sysctl_uts_string which properly fetches the values
and does the proper locking.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
kernel/sysctl.c | 37 ++++++++++++++++++++++++++++++++-----
1 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 0521884..63db5a5 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -136,6 +136,10 @@ #endif
static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos);

+static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen,
+ void __user *oldval, size_t __user *oldlenp,
+ void __user *newval, size_t newlen, void **context);
+
#ifdef CONFIG_PROC_SYSCTL
static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos);
@@ -257,7 +261,7 @@ static ctl_table kern_table[] = {
.maxlen = sizeof(init_uts_ns.name.sysname),
.mode = 0444,
.proc_handler = &proc_do_uts_string,
- .strategy = &sysctl_string,
+ .strategy = &sysctl_uts_string,
},
{
.ctl_name = KERN_OSRELEASE,
@@ -266,7 +270,7 @@ static ctl_table kern_table[] = {
.maxlen = sizeof(init_uts_ns.name.release),
.mode = 0444,
.proc_handler = &proc_do_uts_string,
- .strategy = &sysctl_string,
+ .strategy = &sysctl_uts_string,
},
{
.ctl_name = KERN_VERSION,
@@ -275,7 +279,7 @@ static ctl_table kern_table[] = {
.maxlen = sizeof(init_uts_ns.name.version),
.mode = 0444,
.proc_handler = &proc_do_uts_string,
- .strategy = &sysctl_string,
+ .strategy = &sysctl_uts_string,
},
{
.ctl_name = KERN_NODENAME,
@@ -284,7 +288,7 @@ static ctl_table kern_table[] = {
.maxlen = sizeof(init_uts_ns.name.nodename),
.mode = 0644,
.proc_handler = &proc_do_uts_string,
- .strategy = &sysctl_string,
+ .strategy = &sysctl_uts_string,
},
{
.ctl_name = KERN_DOMAINNAME,
@@ -293,7 +297,7 @@ static ctl_table kern_table[] = {
.maxlen = sizeof(init_uts_ns.name.domainname),
.mode = 0644,
.proc_handler = &proc_do_uts_string,
- .strategy = &sysctl_string,
+ .strategy = &sysctl_uts_string,
},
{
.ctl_name = KERN_PANIC,
@@ -2600,6 +2604,23 @@ int sysctl_ms_jiffies(ctl_table *table,
return 1;
}

+
+/* The generic string strategy routine: */
+static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen,
+ void __user *oldval, size_t __user *oldlenp,
+ void __user *newval, size_t newlen, void **context)
+{
+ struct ctl_table uts_table;
+ int r, write;
+ write = newval && newlen;
+ memcpy(&uts_table, table, sizeof(uts_table));
+ uts_table.data = get_uts(table, write);
+ r = sysctl_string(&uts_table, name, nlen,
+ oldval, oldlenp, newval, newlen, context);
+ put_uts(table, write, uts_table.data);
+ return r;
+}
+
#else /* CONFIG_SYSCTL_SYSCALL */


@@ -2664,6 +2685,12 @@ int sysctl_ms_jiffies(ctl_table *table,
return -ENOSYS;
}

+static int sysctl_uts_string(ctl_table *table, int __user *name, int nlen,
+ void __user *oldval, size_t __user *oldlenp,
+ void __user *newval, size_t newlen, void **context)
+{
+ return -ENOSYS;
+}
#endif /* CONFIG_SYSCTL_SYSCALL */

/*
--
1.4.2.rc3.g7e18e-dirty
-
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