Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
sysctl: Add optional range checking to SYSCTL_INT_CONV_CUSTOM
Extend the SYSCTL_INT_CONV_CUSTOM macro with a k_ptr_range_check
parameter to conditionally generate range validation code. When enabled,
validation is done against table->extra1 (min) and table->extra2 (max)
bounds before assignment. Add base minmax and ms_jiffies_minmax
converter instances that utilize the range checking functionality.
Signed-off-by: Joel Granados <joel.granados@kernel.org>
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kernel/sysctl.c
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kernel/sysctl.c
···
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return 0; \
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}
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/**
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* To range check on a converted value, use a temp k_ptr
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* When checking range, value should be within (tbl->extra1, tbl->extra2)
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*/
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#define SYSCTL_INT_CONV_CUSTOM(name, user_to_kern, kern_to_user, \
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k_ptr_range_check) \
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int do_proc_int_conv##name(bool *negp, unsigned long *u_ptr, int *k_ptr,\
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int dir, const struct ctl_table *tbl) \
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{ \
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if (SYSCTL_KERN_TO_USER(dir)) \
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return kern_to_user(negp, u_ptr, k_ptr); \
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\
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if (k_ptr_range_check) { \
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int tmp_k, ret; \
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if (!tbl) \
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return -EINVAL; \
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ret = user_to_kern(negp, u_ptr, &tmp_k); \
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if (ret) \
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return ret; \
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if ((tbl->extra1 && *(int *)tbl->extra1 > tmp_k) || \
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(tbl->extra2 && *(int *)tbl->extra2 < tmp_k)) \
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return -EINVAL; \
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WRITE_ONCE(*k_ptr, tmp_k); \
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} else \
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return user_to_kern(negp, u_ptr, k_ptr); \
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return 0; \
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}
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#define SYSCTL_CONV_IDENTITY(val) val
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#define SYSCTL_CONV_MULT_HZ(val) ((val) * HZ)
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#define SYSCTL_CONV_DIV_HZ(val) ((val) / HZ)
···
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static SYSCTL_USER_TO_KERN_INT_CONV(_ms, msecs_to_jiffies)
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static SYSCTL_KERN_TO_USER_INT_CONV(_ms, jiffies_to_msecs)
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#define SYSCTL_INT_CONV_CUSTOM(name, user_to_kern, kern_to_user) \
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int do_proc_int_conv##name(bool *negp, unsigned long *u_ptr, int *k_ptr,\
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int dir, const struct ctl_table *table) \
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{ \
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if (SYSCTL_USER_TO_KERN(dir)) \
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return user_to_kern(negp, u_ptr, k_ptr); \
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return kern_to_user(negp, u_ptr, k_ptr); \
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}
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static SYSCTL_INT_CONV_CUSTOM(, sysctl_user_to_kern_int_conv,
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sysctl_kern_to_user_int_conv)
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sysctl_kern_to_user_int_conv, false)
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static SYSCTL_INT_CONV_CUSTOM(_jiffies, sysctl_user_to_kern_int_conv_hz,
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sysctl_kern_to_user_int_conv_hz)
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sysctl_kern_to_user_int_conv_hz, false)
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static SYSCTL_INT_CONV_CUSTOM(_userhz_jiffies,
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sysctl_user_to_kern_int_conv_userhz,
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sysctl_kern_to_user_int_conv_userhz)
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sysctl_kern_to_user_int_conv_userhz, false)
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static SYSCTL_INT_CONV_CUSTOM(_ms_jiffies, sysctl_user_to_kern_int_conv_ms,
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sysctl_kern_to_user_int_conv_ms)
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sysctl_kern_to_user_int_conv_ms, false)
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static SYSCTL_INT_CONV_CUSTOM(_minmax, sysctl_user_to_kern_int_conv,
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sysctl_kern_to_user_int_conv, true)
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static SYSCTL_INT_CONV_CUSTOM(_ms_jiffies_minmax,
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sysctl_user_to_kern_int_conv_ms,
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sysctl_kern_to_user_int_conv_ms, true)
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static int do_proc_douintvec_conv(unsigned long *u_ptr,
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unsigned int *k_ptr, int dir,
···
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do_proc_douintvec_conv);
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}
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static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *u_ptr,
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int *k_ptr, int dir,
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const struct ctl_table *table)
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{
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int tmp, ret, *min, *max;
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/*
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* If writing to a kernel variable, first do so via a temporary
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* local int so we can bounds-check it before touching *k_ptr.
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*/
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int *ip = SYSCTL_USER_TO_KERN(dir) ? &tmp : k_ptr;
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ret = do_proc_int_conv(negp, u_ptr, ip, dir, table);
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if (ret)
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return ret;
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if (SYSCTL_USER_TO_KERN(dir)) {
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min = (int *) table->extra1;
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max = (int *) table->extra2;
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if ((min && *min > tmp) || (max && *max < tmp))
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return -EINVAL;
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WRITE_ONCE(*k_ptr, tmp);
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}
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return 0;
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}
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/**
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* proc_dointvec_minmax - read a vector of integers with min/max values
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* @table: the sysctl table
···
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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return do_proc_dointvec(table, dir, buffer, lenp, ppos,
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do_proc_dointvec_minmax_conv);
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do_proc_int_conv_minmax);
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}
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static int do_proc_douintvec_minmax_conv(unsigned long *u_ptr,
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lenp, ppos, HZ, 1000l);
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}
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static int do_proc_dointvec_ms_jiffies_minmax_conv(bool *negp, unsigned long *u_ptr,
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int *k_ptr, int dir,
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const struct ctl_table *table)
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{
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int tmp, ret, *min, *max;
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/*
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* If writing to a kernel var, first do so via a temporary local
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* int so we can bounds-check it before touching *k_ptr.
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*/
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int *ip = SYSCTL_USER_TO_KERN(dir) ? &tmp : k_ptr;
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ret = do_proc_int_conv_ms_jiffies(negp, u_ptr, ip, dir, table);
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if (ret)
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return ret;
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if (SYSCTL_USER_TO_KERN(dir)) {
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min = (int *) table->extra1;
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max = (int *) table->extra2;
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if ((min && *min > tmp) || (max && *max < tmp))
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return -EINVAL;
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*k_ptr = tmp;
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}
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return 0;
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}
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/**
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* proc_dointvec_jiffies - read a vector of integers as seconds
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* @table: the sysctl table
···
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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return do_proc_dointvec(table, dir, buffer, lenp, ppos,
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do_proc_dointvec_ms_jiffies_minmax_conv);
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do_proc_int_conv_ms_jiffies_minmax);
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}
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/**