Commit 8fc344a5 authored by Joel Granados's avatar Joel Granados
Browse files

sysctl: Replace UINT converter macros with functions 



Replace the SYSCTL_USER_TO_KERN_UINT_CONV and SYSCTL_UINT_CONV_CUSTOM
macros with functions with the same logic. This makes debugging easier
and aligns with the functions preference described in coding-style.rst.
Update the only user of this API: pipe.c.

Signed-off-by: default avatarJoel Granados <joel.granados@kernel.org>
parent 6036dc03

fs/pipe.c

+18 −4
Original line number Diff line number Diff line
@@ -1481,10 +1481,24 @@ static struct file_system_type pipe_fs_type = { 
};



#ifdef CONFIG_SYSCTL

static SYSCTL_USER_TO_KERN_UINT_CONV(_pipe_maxsz, round_pipe_size)

static SYSCTL_UINT_CONV_CUSTOM(_pipe_maxsz,

			       sysctl_user_to_kern_uint_conv_pipe_maxsz,

			       sysctl_kern_to_user_uint_conv, true)



static ulong round_pipe_size_ul(ulong size)

{

	return round_pipe_size(size);

}



static int u2k_pipe_maxsz(const ulong *u_ptr, uint *k_ptr)

{

	return proc_uint_u2k_conv_uop(u_ptr, k_ptr, round_pipe_size_ul);

}



static int do_proc_uint_conv_pipe_maxsz(ulong *u_ptr, uint *k_ptr,

					int dir, const struct ctl_table *table)

{

	return proc_uint_conv(u_ptr, k_ptr, dir, table, true,

			      u2k_pipe_maxsz,

			      proc_uint_k2u_conv);

}



static int proc_dopipe_max_size(const struct ctl_table *table, int write,

				void *buffer, size_t *lenp, loff_t *ppos)

include/linux/sysctl.h

+7 −56
Original line number Diff line number Diff line
@@ -135,45 +135,6 @@ int do_proc_int_conv##name(bool *negp, unsigned long *u_ptr, int *k_ptr,\ 
		return user_to_kern(negp, u_ptr, k_ptr);		\

	return 0;							\

}



#define SYSCTL_USER_TO_KERN_UINT_CONV(name, u_ptr_op)		\

int sysctl_user_to_kern_uint_conv##name(const unsigned long *u_ptr,\

					unsigned int *k_ptr)	\

{								\

	unsigned long u = u_ptr_op(*u_ptr);			\

	if (u > UINT_MAX)					\

		return -EINVAL;					\

	WRITE_ONCE(*k_ptr, u);					\

	return 0;						\

}



#define SYSCTL_UINT_CONV_CUSTOM(name, user_to_kern, kern_to_user,	\

				k_ptr_range_check)			\

int do_proc_uint_conv##name(unsigned long *u_ptr, unsigned int *k_ptr,	\

			   int dir, const struct ctl_table *tbl)	\

{									\

	if (SYSCTL_KERN_TO_USER(dir))					\

		return kern_to_user(u_ptr, k_ptr);			\

									\

	if (k_ptr_range_check) {					\

		unsigned int tmp_k;					\

		int ret;						\

		if (!tbl)						\

			return -EINVAL;					\

		ret = user_to_kern(u_ptr, &tmp_k);			\

		if (ret)						\

			return ret;					\

		if ((tbl->extra1 &&					\

		     *(unsigned int *)tbl->extra1 > tmp_k) ||		\

		    (tbl->extra2 &&					\

		     *(unsigned int *)tbl->extra2 < tmp_k))		\

			return -ERANGE;					\

		WRITE_ONCE(*k_ptr, tmp_k);				\

	} else								\

		return user_to_kern(u_ptr, k_ptr);			\

	return 0;							\

}



#else // CONFIG_PROC_SYSCTL

#define SYSCTL_USER_TO_KERN_INT_CONV(name, u_ptr_op)		\

int sysctl_user_to_kern_int_conv##name(const bool *negp,	\
@@ -199,24 +160,8 @@ int do_proc_int_conv##name(bool *negp, unsigned long *u_ptr, int *k_ptr,\ 
	return -ENOSYS;							\

}



#define SYSCTL_USER_TO_KERN_UINT_CONV(name, u_ptr_op)		\

int sysctl_user_to_kern_uint_conv##name(const unsigned long *u_ptr,\

					unsigned int *k_ptr)	\

{								\

	return -ENOSYS;						\

}



#define SYSCTL_UINT_CONV_CUSTOM(name, user_to_kern, kern_to_user,	\

				k_ptr_range_check)			\

int do_proc_uint_conv##name(unsigned long *u_ptr, unsigned int *k_ptr,	\

			   int dir, const struct ctl_table *tbl)	\

{									\

	return -ENOSYS;							\

}



#endif // CONFIG_PROC_SYSCTL





extern const unsigned long sysctl_long_vals[];



typedef int proc_handler(const struct ctl_table *ctl, int write, void *buffer,
@@ -239,6 +184,13 @@ int proc_douintvec_conv(const struct ctl_table *table, int write, void *buffer, 
			size_t *lenp, loff_t *ppos,

			int (*conv)(unsigned long *lvalp, unsigned int *valp,

				    int write, const struct ctl_table *table));

int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr);

int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr,

			   ulong (*u_ptr_op)(const ulong));

int proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,

		   const struct ctl_table *tbl, bool k_ptr_range_check,

		   int (*user_to_kern)(const ulong *u_ptr, uint *k_ptr),

		   int (*kern_to_user)(ulong *u_ptr, const uint *k_ptr));



int proc_dou8vec_minmax(const struct ctl_table *table, int write, void *buffer,

			size_t *lenp, loff_t *ppos);
@@ -249,7 +201,6 @@ int proc_doulongvec_minmax_conv(const struct ctl_table *table, int dir, 
int proc_do_large_bitmap(const struct ctl_table *, int, void *, size_t *, loff_t *);

int proc_do_static_key(const struct ctl_table *table, int write, void *buffer,

		size_t *lenp, loff_t *ppos);

int sysctl_kern_to_user_uint_conv(unsigned long *u_ptr, const unsigned int *k_ptr);



/*

 * Register a set of sysctl names by calling register_sysctl

kernel/sysctl.c

+123 −17
Original line number Diff line number Diff line
@@ -354,29 +354,117 @@ static void proc_put_char(void **buf, size_t *size, char c) 
	}

}



static SYSCTL_USER_TO_KERN_INT_CONV(, SYSCTL_CONV_IDENTITY)

static SYSCTL_KERN_TO_USER_INT_CONV(, SYSCTL_CONV_IDENTITY)



static SYSCTL_INT_CONV_CUSTOM(, sysctl_user_to_kern_int_conv,

			      sysctl_kern_to_user_int_conv, false)

static SYSCTL_INT_CONV_CUSTOM(_minmax, sysctl_user_to_kern_int_conv,

			      sysctl_kern_to_user_int_conv, true)

/**

 * proc_uint_u2k_conv_uop - Assign user value to a kernel pointer

 *

 * @u_ptr: pointer to user space variable

 * @k_ptr: pointer to kernel variable

 * @u_ptr_op: execute this function before assigning to k_ptr

 *

 * Uses WRITE_ONCE to assign value to k_ptr. Executes u_ptr_op if

 * not NULL. Check that the values are less than UINT_MAX to avoid

 * having to support wrap around from userspace.

 *

 * returns 0 on success.

 */

int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr,

			   ulong (*u_ptr_op)(const ulong))

{

	ulong u = u_ptr_op ? u_ptr_op(*u_ptr) : *u_ptr;



	if (u > UINT_MAX)

		return -EINVAL;

	WRITE_ONCE(*k_ptr, u);

	return 0;

}



static SYSCTL_USER_TO_KERN_UINT_CONV(, SYSCTL_CONV_IDENTITY)

/**

 * proc_uint_k2u_conv - Assign kernel value to a user space pointer

 *

 * @u_ptr: pointer to user space variable

 * @k_ptr: pointer to kernel variable

 *

 * Uses READ_ONCE to assign value to u_ptr.

 *

 * returns 0 on success.

 */

int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr)

{

	uint val = READ_ONCE(*k_ptr);

	*u_ptr = (ulong)val;

	return 0;

}



int sysctl_kern_to_user_uint_conv(unsigned long *u_ptr,

				  const unsigned int *k_ptr)

/**

 * proc_uint_conv - Change user or kernel pointer based on direction

 *

 * @u_ptr: pointer to user variable

 * @k_ptr: pointer to kernel variable

 * @dir: %TRUE if this is a write to the sysctl file

 * @tbl: the sysctl table

 * @k_ptr_range_check: Check range for k_ptr when %TRUE

 * @user_to_kern: Callback used to assign value from user to kernel var

 * @kern_to_user: Callback used to assign value from kernel to user var

 *

 * When direction is kernel to user, then the u_ptr is modified.

 * When direction is user to kernel, then the k_ptr is modified.

 *

 * Returns 0 on success

 */

int proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,

		   const struct ctl_table *tbl, bool k_ptr_range_check,

		   int (*user_to_kern)(const ulong *u_ptr, uint *k_ptr),

		   int (*kern_to_user)(ulong *u_ptr, const uint *k_ptr))

{

	unsigned int val = READ_ONCE(*k_ptr);

	*u_ptr = (unsigned long)val;

	if (SYSCTL_KERN_TO_USER(dir))

		return kern_to_user(u_ptr, k_ptr);



	if (k_ptr_range_check) {

		uint tmp_k;

		int ret;



		if (!tbl)

			return -EINVAL;

		ret = user_to_kern(u_ptr, &tmp_k);

		if (ret)

			return ret;

		if ((tbl->extra1 &&

		     *(uint *)tbl->extra1 > tmp_k) ||

		    (tbl->extra2 &&

		     *(uint *)tbl->extra2 < tmp_k))

			return -ERANGE;

		WRITE_ONCE(*k_ptr, tmp_k);

	} else

		return user_to_kern(u_ptr, k_ptr);

	return 0;

}



static SYSCTL_UINT_CONV_CUSTOM(, sysctl_user_to_kern_uint_conv,

			       sysctl_kern_to_user_uint_conv, false)

static SYSCTL_UINT_CONV_CUSTOM(_minmax, sysctl_user_to_kern_uint_conv,

			       sysctl_kern_to_user_uint_conv, true)

static int proc_uint_u2k_conv(const ulong *u_ptr, uint *k_ptr)

{

	return proc_uint_u2k_conv_uop(u_ptr, k_ptr, NULL);

}



static int do_proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,

			     const struct ctl_table *tbl)

{

	return proc_uint_conv(u_ptr, k_ptr, dir, tbl, false,

			      proc_uint_u2k_conv, proc_uint_k2u_conv);

}



static int do_proc_uint_conv_minmax(ulong *u_ptr, uint *k_ptr, int dir,

				    const struct ctl_table *tbl)

{

	return proc_uint_conv(u_ptr, k_ptr, dir, tbl, true,

			      proc_uint_u2k_conv, proc_uint_k2u_conv);

}



static SYSCTL_USER_TO_KERN_INT_CONV(, SYSCTL_CONV_IDENTITY)

static SYSCTL_KERN_TO_USER_INT_CONV(, SYSCTL_CONV_IDENTITY)



static SYSCTL_INT_CONV_CUSTOM(, sysctl_user_to_kern_int_conv,

			      sysctl_kern_to_user_int_conv, false)

static SYSCTL_INT_CONV_CUSTOM(_minmax, sysctl_user_to_kern_int_conv,

			      sysctl_kern_to_user_int_conv, true)



static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
@@ -576,7 +664,6 @@ int proc_douintvec_conv(const struct ctl_table *table, int dir, void *buffer, 
	return do_proc_douintvec(table, dir, buffer, lenp, ppos, conv);

}





/**

 * proc_dobool - read/write a bool

 * @table: the sysctl table
@@ -1079,6 +1166,25 @@ int proc_douintvec_conv(const struct ctl_table *table, int write, void *buffer, 
	return -ENOSYS;

}



int proc_uint_k2u_conv(ulong *u_ptr, const uint *k_ptr)

{

	return -ENOSYS;

}



int proc_uint_u2k_conv_uop(const ulong *u_ptr, uint *k_ptr,

			   ulong (*u_ptr_op)(const ulong))

{

	return -ENOSYS;

}



int proc_uint_conv(ulong *u_ptr, uint *k_ptr, int dir,

		   const struct ctl_table *tbl, bool k_ptr_range_check,

		   int (*user_to_kern)(const ulong *u_ptr, uint *k_ptr),

		   int (*kern_to_user)(ulong *u_ptr, const uint *k_ptr))

{

	return -ENOSYS;

}



int proc_dou8vec_minmax(const struct ctl_table *table, int dir,

			void *buffer, size_t *lenp, loff_t *ppos)

{