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sysctl: add unsigned int range support

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To keep parity with regular int interfaces provide the an unsigned int
proc_douintvec_minmax() which allows you to specify a range of allowed
valid numbers.

Adding proc_douintvec_minmax_sysadmin() is easy but we can wait for an
actual user for that.

Link: http://lkml.kernel.org/r/20170519033554.18592-6-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Luis R. Rodriguez 2017-07-12 14:33:40 -07:00 committed by Linus Torvalds
parent 4f2fec00af
commit 61d9b56a89
3 changed files with 72 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/proc/proc_sysctl.c
View File

@ -1065,7 +1065,8 @@ static int sysctl_check_table_array(const char *path, struct ctl_table *table)
{
int err = 0;
if (table->proc_handler == proc_douintvec) {
if ((table->proc_handler == proc_douintvec) ||
(table->proc_handler == proc_douintvec_minmax)) {
if (table->maxlen != sizeof(unsigned int))
err |= sysctl_err(path, table, "array now allowed");
}
@ -1083,6 +1084,7 @@ static int sysctl_check_table(const char *path, struct ctl_table *table)
if ((table->proc_handler == proc_dostring) ||
(table->proc_handler == proc_dointvec) ||
(table->proc_handler == proc_douintvec) ||
(table->proc_handler == proc_douintvec_minmax) ||
(table->proc_handler == proc_dointvec_minmax) ||
(table->proc_handler == proc_dointvec_jiffies) ||
(table->proc_handler == proc_dointvec_userhz_jiffies) ||

3
include/linux/sysctl.h
View File

@ -47,6 +47,9 @@ extern int proc_douintvec(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_dointvec_minmax(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_douintvec_minmax(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
extern int proc_dointvec_jiffies(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_dointvec_userhz_jiffies(struct ctl_table *, int,

66
kernel/sysctl.c
View File

@ -2567,6 +2567,65 @@ int proc_dointvec_minmax(struct ctl_table *table, int write,
do_proc_dointvec_minmax_conv, &param);
}
struct do_proc_douintvec_minmax_conv_param {
unsigned int *min;
unsigned int *max;
};
static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
unsigned int *valp,
int write, void *data)
{
struct do_proc_douintvec_minmax_conv_param *param = data;
if (write) {
unsigned int val = *lvalp;
if ((param->min && *param->min > val) ||
(param->max && *param->max < val))
return -ERANGE;
if (*lvalp > UINT_MAX)
return -EINVAL;
*valp = val;
} else {
unsigned int val = *valp;
*lvalp = (unsigned long) val;
}
return 0;
}
/**
* proc_douintvec_minmax - read a vector of unsigned ints with min/max values
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
* @buffer: the user buffer
* @lenp: the size of the user buffer
* @ppos: file position
*
* Reads/writes up to table->maxlen/sizeof(unsigned int) unsigned integer
* values from/to the user buffer, treated as an ASCII string. Negative
* strings are not allowed.
*
* This routine will ensure the values are within the range specified by
* table->extra1 (min) and table->extra2 (max). There is a final sanity
* check for UINT_MAX to avoid having to support wrap around uses from
* userspace.
*
* Returns 0 on success.
*/
int proc_douintvec_minmax(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct do_proc_douintvec_minmax_conv_param param = {
.min = (unsigned int *) table->extra1,
.max = (unsigned int *) table->extra2,
};
return do_proc_douintvec(table, write, buffer, lenp, ppos,
do_proc_douintvec_minmax_conv, &param);
}
static void validate_coredump_safety(void)
{
#ifdef CONFIG_COREDUMP
@ -3066,6 +3125,12 @@ int proc_dointvec_minmax(struct ctl_table *table, int write,
return -ENOSYS;
}
int proc_douintvec_minmax(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
return -ENOSYS;
}
int proc_dointvec_jiffies(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
@ -3108,6 +3173,7 @@ EXPORT_SYMBOL(proc_dointvec);
EXPORT_SYMBOL(proc_douintvec);
EXPORT_SYMBOL(proc_dointvec_jiffies);
EXPORT_SYMBOL(proc_dointvec_minmax);
EXPORT_SYMBOL_GPL(proc_douintvec_minmax);
EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
EXPORT_SYMBOL(proc_dostring);