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Message-Id: <20251013-jag-sysctl_conv-v1-5-4dc35ceae733@kernel.org>
Date: Mon, 13 Oct 2025 15:24:55 +0200
From: Joel Granados <joel.granados@...nel.org>
To: Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
Kees Cook <kees@...nel.org>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
Joel Granados <joel.granados@...nel.org>
Subject: [PATCH 5/8] sysctl: Discriminate between kernel and user converter
params
Rename converter parameter to indicate data flow direction: "lvalp" to
"u_ptr" indicating a user space parsed value pointer. "valp" to "k_ptr"
indicating a kernel storage value pointer. This facilitates the
identification of discrepancies between direction (copy to kernel or
copy to user space) and the modified variable. This is a preparation
commit for when the converter functions are exposed to the rest of the
kernel.
Signed-off-by: Joel Granados <joel.granados@...nel.org>
---
kernel/sysctl.c | 118 ++++++++++++++++++++++++++++----------------------------
1 file changed, 59 insertions(+), 59 deletions(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 69148fe7359994b85c076b7b6750792b2d1c751e..2091d2396c83ac68d621b3d158ce1c490c392c4b 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -368,44 +368,44 @@ static void proc_put_char(void **buf, size_t *size, char c)
}
}
-static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
- int *valp, int dir,
+static int do_proc_dointvec_conv(bool *negp, unsigned long *u_ptr,
+ int *k_ptr, int dir,
const struct ctl_table *table)
{
if (SYSCTL_USER_TO_KERN(dir)) {
if (*negp) {
- if (*lvalp > (unsigned long) INT_MAX + 1)
+ if (*u_ptr > (unsigned long) INT_MAX + 1)
return -EINVAL;
- WRITE_ONCE(*valp, -*lvalp);
+ WRITE_ONCE(*k_ptr, -*u_ptr);
} else {
- if (*lvalp > (unsigned long) INT_MAX)
+ if (*u_ptr > (unsigned long) INT_MAX)
return -EINVAL;
- WRITE_ONCE(*valp, *lvalp);
+ WRITE_ONCE(*k_ptr, *u_ptr);
}
} else {
- int val = READ_ONCE(*valp);
+ int val = READ_ONCE(*k_ptr);
if (val < 0) {
*negp = true;
- *lvalp = -(unsigned long)val;
+ *u_ptr = -(unsigned long)val;
} else {
*negp = false;
- *lvalp = (unsigned long)val;
+ *u_ptr = (unsigned long)val;
}
}
return 0;
}
-static int do_proc_douintvec_conv(unsigned long *lvalp,
- unsigned int *valp, int dir,
+static int do_proc_douintvec_conv(unsigned long *u_ptr,
+ unsigned int *k_ptr, int dir,
const struct ctl_table *table)
{
if (SYSCTL_USER_TO_KERN(dir)) {
- if (*lvalp > UINT_MAX)
+ if (*u_ptr > UINT_MAX)
return -EINVAL;
- WRITE_ONCE(*valp, *lvalp);
+ WRITE_ONCE(*k_ptr, *u_ptr);
} else {
- unsigned int val = READ_ONCE(*valp);
- *lvalp = (unsigned long)val;
+ unsigned int val = READ_ONCE(*k_ptr);
+ *u_ptr = (unsigned long)val;
}
return 0;
}
@@ -415,7 +415,7 @@ static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
static int do_proc_dointvec(const struct ctl_table *table, int dir,
void *buffer, size_t *lenp, loff_t *ppos,
- int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
+ int (*conv)(bool *negp, unsigned long *u_ptr, int *k_ptr,
int dir, const struct ctl_table *table))
{
int *i, vleft, first = 1, err = 0;
@@ -487,8 +487,8 @@ static int do_proc_dointvec(const struct ctl_table *table, int dir,
static int do_proc_douintvec_w(const struct ctl_table *table, void *buffer,
size_t *lenp, loff_t *ppos,
- int (*conv)(unsigned long *lvalp,
- unsigned int *valp, int dir,
+ int (*conv)(unsigned long *u_ptr,
+ unsigned int *k_ptr, int dir,
const struct ctl_table *table))
{
unsigned long lval;
@@ -540,8 +540,8 @@ static int do_proc_douintvec_w(const struct ctl_table *table, void *buffer,
static int do_proc_douintvec_r(const struct ctl_table *table, void *buffer,
size_t *lenp, loff_t *ppos,
- int (*conv)(unsigned long *lvalp,
- unsigned int *valp, int dir,
+ int (*conv)(unsigned long *u_ptr,
+ unsigned int *k_ptr, int dir,
const struct ctl_table *table))
{
unsigned long lval;
@@ -570,7 +570,7 @@ static int do_proc_douintvec_r(const struct ctl_table *table, void *buffer,
int do_proc_douintvec(const struct ctl_table *table, int dir, void *buffer,
size_t *lenp, loff_t *ppos,
- int (*conv)(unsigned long *lvalp, unsigned int *valp,
+ int (*conv)(unsigned long *u_ptr, unsigned int *k_ptr,
int dir, const struct ctl_table *table))
{
unsigned int vleft;
@@ -679,18 +679,18 @@ int proc_douintvec(const struct ctl_table *table, int dir, void *buffer,
do_proc_douintvec_conv);
}
-static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
- int *valp, int dir,
+static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *u_ptr,
+ int *k_ptr, int dir,
const struct ctl_table *table)
{
int tmp, ret, *min, *max;
/*
- * If writing, first do so via a temporary local int so we can
- * bounds-check it before touching *valp.
+ * If writing to a kernel variable, first do so via a temporary
+ * local int so we can bounds-check it before touching *k_ptr.
*/
- int *ip = SYSCTL_USER_TO_KERN(dir) ? &tmp : valp;
+ int *ip = SYSCTL_USER_TO_KERN(dir) ? &tmp : k_ptr;
- ret = do_proc_dointvec_conv(negp, lvalp, ip, dir, table);
+ ret = do_proc_dointvec_conv(negp, u_ptr, ip, dir, table);
if (ret)
return ret;
@@ -699,7 +699,7 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
max = (int *) table->extra2;
if ((min && *min > tmp) || (max && *max < tmp))
return -EINVAL;
- WRITE_ONCE(*valp, tmp);
+ WRITE_ONCE(*k_ptr, tmp);
}
return 0;
@@ -729,16 +729,16 @@ int proc_dointvec_minmax(const struct ctl_table *table, int dir,
do_proc_dointvec_minmax_conv);
}
-static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
- unsigned int *valp, int dir,
+static int do_proc_douintvec_minmax_conv(unsigned long *u_ptr,
+ unsigned int *k_ptr, int dir,
const struct ctl_table *table)
{
int ret;
unsigned int tmp, *min, *max;
/* When writing to the kernel use a temp local uint for bounds-checking */
- unsigned int *up = SYSCTL_USER_TO_KERN(dir) ? &tmp : valp;
+ unsigned int *up = SYSCTL_USER_TO_KERN(dir) ? &tmp : k_ptr;
- ret = do_proc_douintvec_conv(lvalp, up, dir, table);
+ ret = do_proc_douintvec_conv(u_ptr, up, dir, table);
if (ret)
return ret;
@@ -748,7 +748,7 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
if ((min && *min > tmp) || (max && *max < tmp))
return -ERANGE;
- WRITE_ONCE(*valp, tmp);
+ WRITE_ONCE(*k_ptr, tmp);
}
return 0;
@@ -953,19 +953,19 @@ int proc_doulongvec_ms_jiffies_minmax(const struct ctl_table *table, int dir,
}
-static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
- int *valp, int dir,
+static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *u_ptr,
+ int *k_ptr, int dir,
const struct ctl_table *table)
{
if (SYSCTL_USER_TO_KERN(dir)) {
- if (*lvalp > INT_MAX / HZ)
+ if (*u_ptr > INT_MAX / HZ)
return 1;
if (*negp)
- WRITE_ONCE(*valp, -*lvalp * HZ);
+ WRITE_ONCE(*k_ptr, -*u_ptr * HZ);
else
- WRITE_ONCE(*valp, *lvalp * HZ);
+ WRITE_ONCE(*k_ptr, *u_ptr * HZ);
} else {
- int val = READ_ONCE(*valp);
+ int val = READ_ONCE(*k_ptr);
unsigned long lval;
if (val < 0) {
*negp = true;
@@ -974,21 +974,21 @@ static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
*negp = false;
lval = (unsigned long)val;
}
- *lvalp = lval / HZ;
+ *u_ptr = lval / HZ;
}
return 0;
}
-static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
- int *valp, int dir,
+static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *u_ptr,
+ int *k_ptr, int dir,
const struct ctl_table *table)
{
if (SYSCTL_USER_TO_KERN(dir)) {
- if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
+ if (USER_HZ < HZ && (LONG_MAX / HZ) * USER_HZ < *u_ptr)
return 1;
- *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
+ *k_ptr = clock_t_to_jiffies(*negp ? -*u_ptr : *u_ptr);
} else {
- int val = *valp;
+ int val = *k_ptr;
unsigned long lval;
if (val < 0) {
*negp = true;
@@ -997,23 +997,23 @@ static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp
*negp = false;
lval = (unsigned long)val;
}
- *lvalp = jiffies_to_clock_t(lval);
+ *u_ptr = jiffies_to_clock_t(lval);
}
return 0;
}
-static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
- int *valp, int dir,
+static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *u_ptr,
+ int *k_ptr, int dir,
const struct ctl_table *table)
{
if (SYSCTL_USER_TO_KERN(dir)) {
- unsigned long jif = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
+ unsigned long jif = msecs_to_jiffies(*negp ? -*u_ptr : *u_ptr);
if (jif > INT_MAX)
return 1;
- WRITE_ONCE(*valp, (int)jif);
+ WRITE_ONCE(*k_ptr, (int)jif);
} else {
- int val = READ_ONCE(*valp);
+ int val = READ_ONCE(*k_ptr);
unsigned long lval;
if (val < 0) {
*negp = true;
@@ -1022,23 +1022,23 @@ static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
*negp = false;
lval = (unsigned long)val;
}
- *lvalp = jiffies_to_msecs(lval);
+ *u_ptr = jiffies_to_msecs(lval);
}
return 0;
}
-static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lvalp,
- int *valp, int dir,
+static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *u_ptr,
+ int *k_ptr, int dir,
const struct ctl_table *table)
{
int tmp, ret, *min, *max;
/*
- * If writing, first do so via a temporary local int so we can
- * bounds-check it before touching *valp.
+ * If writing to a kernel var, first do so via a temporary local
+ * int so we can bounds-check it before touching *k_ptr.
*/
- int *ip = SYSCTL_USER_TO_KERN(dir) ? &tmp : valp;
+ int *ip = SYSCTL_USER_TO_KERN(dir) ? &tmp : k_ptr;
- ret = do_proc_dointvec_ms_jiffies_conv(negp, lvalp, ip, dir, table);
+ ret = do_proc_dointvec_ms_jiffies_conv(negp, u_ptr, ip, dir, table);
if (ret)
return ret;
@@ -1047,7 +1047,7 @@ static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *lv
max = (int *) table->extra2;
if ((min && *min > tmp) || (max && *max < tmp))
return -EINVAL;
- *valp = tmp;
+ *k_ptr = tmp;
}
return 0;
}
--
2.50.1
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