summaryrefslogtreecommitdiff
path: root/kernel/sysctl.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r--kernel/sysctl.c103
1 files changed, 85 insertions, 18 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 74f5b580fe34..db19e3e2aa4b 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -173,6 +173,13 @@ extern int no_unaligned_warning;
#endif
#ifdef CONFIG_PROC_SYSCTL
+
+#define SYSCTL_WRITES_LEGACY -1
+#define SYSCTL_WRITES_WARN 0
+#define SYSCTL_WRITES_STRICT 1
+
+static int sysctl_writes_strict = SYSCTL_WRITES_WARN;
+
static int proc_do_cad_pid(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
static int proc_taint(struct ctl_table *table, int write,
@@ -195,7 +202,7 @@ static int proc_dostring_coredump(struct ctl_table *table, int write,
/* Note: sysrq code uses it's own private copy */
static int __sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE;
-static int sysrq_sysctl_handler(ctl_table *table, int write,
+static int sysrq_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
@@ -495,6 +502,15 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = proc_taint,
},
+ {
+ .procname = "sysctl_writes_strict",
+ .data = &sysctl_writes_strict,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &neg_one,
+ .extra2 = &one,
+ },
#endif
#ifdef CONFIG_LATENCYTOP
{
@@ -643,7 +659,7 @@ static struct ctl_table kern_table[] = {
.extra2 = &one,
},
#endif
-
+#ifdef CONFIG_UEVENT_HELPER
{
.procname = "hotplug",
.data = &uevent_helper,
@@ -651,7 +667,7 @@ static struct ctl_table kern_table[] = {
.mode = 0644,
.proc_handler = proc_dostring,
},
-
+#endif
#ifdef CONFIG_CHR_DEV_SG
{
.procname = "sg-big-buff",
@@ -1418,8 +1434,13 @@ static struct ctl_table vm_table[] = {
(defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
{
.procname = "vdso_enabled",
+#ifdef CONFIG_X86_32
+ .data = &vdso32_enabled,
+ .maxlen = sizeof(vdso32_enabled),
+#else
.data = &vdso_enabled,
.maxlen = sizeof(vdso_enabled),
+#endif
.mode = 0644,
.proc_handler = proc_dointvec,
.extra1 = &zero,
@@ -1698,8 +1719,8 @@ int __init sysctl_init(void)
#ifdef CONFIG_PROC_SYSCTL
-static int _proc_do_string(void* data, int maxlen, int write,
- void __user *buffer,
+static int _proc_do_string(char *data, int maxlen, int write,
+ char __user *buffer,
size_t *lenp, loff_t *ppos)
{
size_t len;
@@ -1712,21 +1733,30 @@ static int _proc_do_string(void* data, int maxlen, int write,
}
if (write) {
- len = 0;
+ if (sysctl_writes_strict == SYSCTL_WRITES_STRICT) {
+ /* Only continue writes not past the end of buffer. */
+ len = strlen(data);
+ if (len > maxlen - 1)
+ len = maxlen - 1;
+
+ if (*ppos > len)
+ return 0;
+ len = *ppos;
+ } else {
+ /* Start writing from beginning of buffer. */
+ len = 0;
+ }
+
+ *ppos += *lenp;
p = buffer;
- while (len < *lenp) {
+ while ((p - buffer) < *lenp && len < maxlen - 1) {
if (get_user(c, p++))
return -EFAULT;
if (c == 0 || c == '\n')
break;
- len++;
+ data[len++] = c;
}
- if (len >= maxlen)
- len = maxlen-1;
- if(copy_from_user(data, buffer, len))
- return -EFAULT;
- ((char *) data)[len] = 0;
- *ppos += *lenp;
+ data[len] = 0;
} else {
len = strlen(data);
if (len > maxlen)
@@ -1743,10 +1773,10 @@ static int _proc_do_string(void* data, int maxlen, int write,
if (len > *lenp)
len = *lenp;
if (len)
- if(copy_to_user(buffer, data, len))
+ if (copy_to_user(buffer, data, len))
return -EFAULT;
if (len < *lenp) {
- if(put_user('\n', ((char __user *) buffer) + len))
+ if (put_user('\n', buffer + len))
return -EFAULT;
len++;
}
@@ -1756,6 +1786,14 @@ static int _proc_do_string(void* data, int maxlen, int write,
return 0;
}
+static void warn_sysctl_write(struct ctl_table *table)
+{
+ pr_warn_once("%s wrote to %s when file position was not 0!\n"
+ "This will not be supported in the future. To silence this\n"
+ "warning, set kernel.sysctl_writes_strict = -1\n",
+ current->comm, table->procname);
+}
+
/**
* proc_dostring - read a string sysctl
* @table: the sysctl table
@@ -1776,8 +1814,11 @@ static int _proc_do_string(void* data, int maxlen, int write,
int proc_dostring(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
- return _proc_do_string(table->data, table->maxlen, write,
- buffer, lenp, ppos);
+ if (write && *ppos && sysctl_writes_strict == SYSCTL_WRITES_WARN)
+ warn_sysctl_write(table);
+
+ return _proc_do_string((char *)(table->data), table->maxlen, write,
+ (char __user *)buffer, lenp, ppos);
}
static size_t proc_skip_spaces(char **buf)
@@ -1951,6 +1992,18 @@ static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
conv = do_proc_dointvec_conv;
if (write) {
+ if (*ppos) {
+ switch (sysctl_writes_strict) {
+ case SYSCTL_WRITES_STRICT:
+ goto out;
+ case SYSCTL_WRITES_WARN:
+ warn_sysctl_write(table);
+ break;
+ default:
+ break;
+ }
+ }
+
if (left > PAGE_SIZE - 1)
left = PAGE_SIZE - 1;
page = __get_free_page(GFP_TEMPORARY);
@@ -2008,6 +2061,7 @@ free:
return err ? : -EINVAL;
}
*lenp -= left;
+out:
*ppos += *lenp;
return err;
}
@@ -2200,6 +2254,18 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int
left = *lenp;
if (write) {
+ if (*ppos) {
+ switch (sysctl_writes_strict) {
+ case SYSCTL_WRITES_STRICT:
+ goto out;
+ case SYSCTL_WRITES_WARN:
+ warn_sysctl_write(table);
+ break;
+ default:
+ break;
+ }
+ }
+
if (left > PAGE_SIZE - 1)
left = PAGE_SIZE - 1;
page = __get_free_page(GFP_TEMPORARY);
@@ -2255,6 +2321,7 @@ free:
return err ? : -EINVAL;
}
*lenp -= left;
+out:
*ppos += *lenp;
return err;
}