linux/net/sunrpc/sysctl.c
Linus Torvalds 96d4f267e4 Remove 'type' argument from access_ok() function
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-03 18:57:57 -08:00

187 lines
3.5 KiB
C

/*
* linux/net/sunrpc/sysctl.c
*
* Sysctl interface to sunrpc module.
*
* I would prefer to register the sunrpc table below sys/net, but that's
* impossible at the moment.
*/
#include <linux/types.h>
#include <linux/linkage.h>
#include <linux/ctype.h>
#include <linux/fs.h>
#include <linux/sysctl.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svc_xprt.h>
#include "netns.h"
/*
* Declare the debug flags here
*/
unsigned int rpc_debug;
EXPORT_SYMBOL_GPL(rpc_debug);
unsigned int nfs_debug;
EXPORT_SYMBOL_GPL(nfs_debug);
unsigned int nfsd_debug;
EXPORT_SYMBOL_GPL(nfsd_debug);
unsigned int nlm_debug;
EXPORT_SYMBOL_GPL(nlm_debug);
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
static struct ctl_table_header *sunrpc_table_header;
static struct ctl_table sunrpc_table[];
void
rpc_register_sysctl(void)
{
if (!sunrpc_table_header)
sunrpc_table_header = register_sysctl_table(sunrpc_table);
}
void
rpc_unregister_sysctl(void)
{
if (sunrpc_table_header) {
unregister_sysctl_table(sunrpc_table_header);
sunrpc_table_header = NULL;
}
}
static int proc_do_xprt(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
char tmpbuf[256];
size_t len;
if ((*ppos && !write) || !*lenp) {
*lenp = 0;
return 0;
}
len = svc_print_xprts(tmpbuf, sizeof(tmpbuf));
return simple_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len);
}
static int
proc_dodebug(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
char tmpbuf[20], c, *s = NULL;
char __user *p;
unsigned int value;
size_t left, len;
if ((*ppos && !write) || !*lenp) {
*lenp = 0;
return 0;
}
left = *lenp;
if (write) {
if (!access_ok(buffer, left))
return -EFAULT;
p = buffer;
while (left && __get_user(c, p) >= 0 && isspace(c))
left--, p++;
if (!left)
goto done;
if (left > sizeof(tmpbuf) - 1)
return -EINVAL;
if (copy_from_user(tmpbuf, p, left))
return -EFAULT;
tmpbuf[left] = '\0';
value = simple_strtol(tmpbuf, &s, 0);
if (s) {
left -= (s - tmpbuf);
if (left && !isspace(*s))
return -EINVAL;
while (left && isspace(*s))
left--, s++;
} else
left = 0;
*(unsigned int *) table->data = value;
/* Display the RPC tasks on writing to rpc_debug */
if (strcmp(table->procname, "rpc_debug") == 0)
rpc_show_tasks(&init_net);
} else {
len = sprintf(tmpbuf, "0x%04x", *(unsigned int *) table->data);
if (len > left)
len = left;
if (copy_to_user(buffer, tmpbuf, len))
return -EFAULT;
if ((left -= len) > 0) {
if (put_user('\n', (char __user *)buffer + len))
return -EFAULT;
left--;
}
}
done:
*lenp -= left;
*ppos += *lenp;
return 0;
}
static struct ctl_table debug_table[] = {
{
.procname = "rpc_debug",
.data = &rpc_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "nfs_debug",
.data = &nfs_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "nfsd_debug",
.data = &nfsd_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "nlm_debug",
.data = &nlm_debug,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dodebug
},
{
.procname = "transports",
.maxlen = 256,
.mode = 0444,
.proc_handler = proc_do_xprt,
},
{ }
};
static struct ctl_table sunrpc_table[] = {
{
.procname = "sunrpc",
.mode = 0555,
.child = debug_table
},
{ }
};
#endif