Commit 551bf184 authored by Joel Granados's avatar Joel Granados
Browse files

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: default avatarJoel Granados <joel.granados@kernel.org>
parent 5412f5b1

kernel/sysctl.c

+59 −59
Original line number Diff line number Diff line
@@ -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;

}