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Message-Id: <20240801131948.10494-1-wen.yang@linux.dev>
Date: Thu, 1 Aug 2024 21:19:48 +0800
From: Wen Yang <wen.yang@...ux.dev>
To: "Eric W . Biederman" <ebiederm@...ssion.com>,
Luis Chamberlain <mcgrof@...nel.org>,
Kees Cook <keescook@...omium.org>,
Joel Granados <j.granados@...sung.com>,
Christian Brauner <brauner@...nel.org>
Cc: Wen Yang <wen.yang@...ux.dev>,
Dave Young <dyoung@...hat.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH v3] sysctl: simplify the min/max boundary check
The do_proc_dointvec_minmax_conv_param structure provides the minimum and
maximum values for doing range checking for the proc_dointvec_minmax()
handler, while the do_proc_douintvec_minmax_conv_param structure also
provides these min/max values for doing range checking for the
proc_douintvec_minmax()/proc_dou8vec_minmax() handlers.
To avoid duplicate code, a new proc_minmax_conv_param structure has been
introduced to replace both do_proc_dointvec_minmax_conv_param and
do_proc_douintvec_minmax_conv_param mentioned above.
This also prepares for the removal of sysctl_vals and sysctl_long_vals.
Signed-off-by: Wen Yang <wen.yang@...ux.dev>
Cc: Luis Chamberlain <mcgrof@...nel.org>
Cc: Kees Cook <keescook@...omium.org>
Cc: Joel Granados <j.granados@...sung.com>
Cc: Eric W. Biederman <ebiederm@...ssion.com>
Cc: Christian Brauner <brauner@...nel.org>
Cc: Dave Young <dyoung@...hat.com>
Cc: linux-kernel@...r.kernel.org
---
kernel/sysctl.c | 93 +++++++++++++++++++------------------------------
1 file changed, 36 insertions(+), 57 deletions(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 79e6cb1d5c48..92305cdbb94a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -809,17 +809,18 @@ static int proc_taint(const struct ctl_table *table, int write,
}
/**
- * struct do_proc_dointvec_minmax_conv_param - proc_dointvec_minmax() range checking structure
- * @min: pointer to minimum allowable value
- * @max: pointer to maximum allowable value
+ * struct proc_minmax_conv_param - proc_dointvec_minmax() range checking structure
+ * @min: the minimum allowable value
+ * @max: the maximum allowable value
*
- * The do_proc_dointvec_minmax_conv_param structure provides the
+ * The proc_minmax_conv_param structure provides the
* minimum and maximum values for doing range checking for those sysctl
- * parameters that use the proc_dointvec_minmax() handler.
+ * parameters that use the proc_dointvec_minmax(), proc_douintvec_minmax(),
+ * proc_dou8vec_minmax() and so on.
*/
-struct do_proc_dointvec_minmax_conv_param {
- int *min;
- int *max;
+struct proc_minmax_conv_param {
+ long min;
+ long max;
};
static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
@@ -827,7 +828,7 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
int write, void *data)
{
int tmp, ret;
- struct do_proc_dointvec_minmax_conv_param *param = data;
+ struct proc_minmax_conv_param *param = data;
/*
* If writing, first do so via a temporary local int so we can
* bounds-check it before touching *valp.
@@ -839,8 +840,7 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
return ret;
if (write) {
- if ((param->min && *param->min > tmp) ||
- (param->max && *param->max < tmp))
+ if ((param->min > tmp) || (param->max < tmp))
return -EINVAL;
WRITE_ONCE(*valp, tmp);
}
@@ -867,35 +867,21 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
int proc_dointvec_minmax(const struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
- struct do_proc_dointvec_minmax_conv_param param = {
- .min = (int *) table->extra1,
- .max = (int *) table->extra2,
- };
+ struct proc_minmax_conv_param param;
+
+ param.min = (table->extra1) ? *(int *) table->extra1 : INT_MIN;
+ param.max = (table->extra2) ? *(int *) table->extra2 : INT_MAX;
return do_proc_dointvec(table, write, buffer, lenp, ppos,
do_proc_dointvec_minmax_conv, ¶m);
}
-/**
- * struct do_proc_douintvec_minmax_conv_param - proc_douintvec_minmax() range checking structure
- * @min: pointer to minimum allowable value
- * @max: pointer to maximum allowable value
- *
- * The do_proc_douintvec_minmax_conv_param structure provides the
- * minimum and maximum values for doing range checking for those sysctl
- * parameters that use the proc_douintvec_minmax() handler.
- */
-struct do_proc_douintvec_minmax_conv_param {
- unsigned int *min;
- unsigned int *max;
-};
-
static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
unsigned int *valp,
int write, void *data)
{
int ret;
unsigned int tmp;
- struct do_proc_douintvec_minmax_conv_param *param = data;
+ struct proc_minmax_conv_param *param = data;
/* write via temporary local uint for bounds-checking */
unsigned int *up = write ? &tmp : valp;
@@ -904,8 +890,7 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
return ret;
if (write) {
- if ((param->min && *param->min > tmp) ||
- (param->max && *param->max < tmp))
+ if ((param->min > tmp) || (param->max < tmp))
return -ERANGE;
WRITE_ONCE(*valp, tmp);
@@ -936,10 +921,10 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
int proc_douintvec_minmax(const struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
- struct do_proc_douintvec_minmax_conv_param param = {
- .min = (unsigned int *) table->extra1,
- .max = (unsigned int *) table->extra2,
- };
+ struct proc_minmax_conv_param param;
+
+ param.min = (table->extra1) ? *(unsigned int *) table->extra1 : 0;
+ param.max = (table->extra2) ? *(unsigned int *) table->extra2 : UINT_MAX;
return do_proc_douintvec(table, write, buffer, lenp, ppos,
do_proc_douintvec_minmax_conv, ¶m);
}
@@ -965,23 +950,17 @@ int proc_dou8vec_minmax(const struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table tmp;
- unsigned int min = 0, max = 255U, val;
+ unsigned int val;
u8 *data = table->data;
- struct do_proc_douintvec_minmax_conv_param param = {
- .min = &min,
- .max = &max,
- };
+ struct proc_minmax_conv_param param;
int res;
/* Do not support arrays yet. */
if (table->maxlen != sizeof(u8))
return -EINVAL;
- if (table->extra1)
- min = *(unsigned int *) table->extra1;
- if (table->extra2)
- max = *(unsigned int *) table->extra2;
-
+ param.min = (table->extra1) ? *(unsigned int *) table->extra1 : 0;
+ param.max = (table->extra2) ? *(unsigned int *) table->extra2 : 255U;
tmp = *table;
tmp.maxlen = sizeof(val);
@@ -1022,7 +1001,7 @@ static int __do_proc_doulongvec_minmax(void *data,
void *buffer, size_t *lenp, loff_t *ppos,
unsigned long convmul, unsigned long convdiv)
{
- unsigned long *i, *min, *max;
+ unsigned long *i, min, max;
int vleft, first = 1, err = 0;
size_t left;
char *p;
@@ -1033,8 +1012,9 @@ static int __do_proc_doulongvec_minmax(void *data,
}
i = data;
- min = table->extra1;
- max = table->extra2;
+ min = (table->extra1) ? *(unsigned long *) table->extra1 : 0;
+ max = (table->extra2) ? *(unsigned long *) table->extra2 : ULONG_MAX;
+
vleft = table->maxlen / sizeof(unsigned long);
left = *lenp;
@@ -1066,7 +1046,7 @@ static int __do_proc_doulongvec_minmax(void *data,
}
val = convmul * val / convdiv;
- if ((min && val < *min) || (max && val > *max)) {
+ if ((val < min) || (val > max)) {
err = -EINVAL;
break;
}
@@ -1224,7 +1204,7 @@ static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lv
int *valp, int write, void *data)
{
int tmp, ret;
- struct do_proc_dointvec_minmax_conv_param *param = data;
+ struct proc_minmax_conv_param *param = data;
/*
* If writing, first do so via a temporary local int so we can
* bounds-check it before touching *valp.
@@ -1236,8 +1216,7 @@ static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lv
return ret;
if (write) {
- if ((param->min && *param->min > tmp) ||
- (param->max && *param->max < tmp))
+ if ((param->min > tmp) || (param->max < tmp))
return -EINVAL;
*valp = tmp;
}
@@ -1269,10 +1248,10 @@ int proc_dointvec_jiffies(const struct ctl_table *table, int write,
int proc_dointvec_ms_jiffies_minmax(const struct ctl_table *table, int write,
void *buffer, size_t *lenp, loff_t *ppos)
{
- struct do_proc_dointvec_minmax_conv_param param = {
- .min = (int *) table->extra1,
- .max = (int *) table->extra2,
- };
+ struct proc_minmax_conv_param param;
+
+ param.min = (table->extra1) ? *(int *) table->extra1 : INT_MIN;
+ param.max = (table->extra2) ? *(int *) table->extra2 : INT_MAX;
return do_proc_dointvec(table, write, buffer, lenp, ppos,
do_proc_dointvec_ms_jiffies_minmax_conv, ¶m);
}
--
2.25.1
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