From 8fc344a5af7e73178e6ac54d396327655e9ea358 Mon Sep 17 00:00:00 2001 From: Joel Granados Date: Fri, 28 Nov 2025 21:53:00 +0100 Subject: 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: Joel Granados --- kernel/sysctl.c | 140 +++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 123 insertions(+), 17 deletions(-) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 4ea56c71c7ef..00df21b84900 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -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) { -- cgit v1.2.3