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kernel/sysctl.c: define minmax conv functions in terms of non-minmax versions 

do_proc_do[u]intvec_minmax_conv() had included open-coded versions of
do_proc_do[u]intvec_conv(); the duplication led to buggy inconsistencies
(missing range checks).  To reduce the likelihood of such problems in the
future, we can instead refactor both to be defined in terms of their
non-bounded counterparts (plus the added check).

Link: http://lkml.kernel.org/r/20190207165138.5oud57vq4ozwb4kh@hatter.bewilderbeest.net
Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Zev Weiss 2019-03-11 23:28:06 -07:00 committed by Linus Torvalds
parent 8cf7630b29
commit 2bc4fc60fb
1 changed files with 26 additions and 33 deletions
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59
kernel/sysctl.c
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@ -2643,32 +2643,25 @@ static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
{
int tmp, ret;
struct do_proc_dointvec_minmax_conv_param *param = data;
/*
* If writing, first do so via a temporary local int so we can
* bounds-check it before touching *valp.
*/
int *ip = write ? &tmp : valp;
ret = do_proc_dointvec_conv(negp, lvalp, ip, write, data);
if (ret)
return ret;
if (write) {
int val;
if (*negp) {
if (*lvalp > (unsigned long) INT_MAX + 1)
return -EINVAL;
val = -*lvalp;
} else {
if (*lvalp > (unsigned long) INT_MAX)
return -EINVAL;
val = *lvalp;
}
if ((param->min && *param->min > val) ||
(param->max && *param->max < val))
if ((param->min && *param->min > tmp) ||
(param->max && *param->max < tmp))
return -EINVAL;
*valp = val;
} else {
int val = *valp;
if (val < 0) {
*negp = true;
*lvalp = -(unsigned long)val;
} else {
*negp = false;
*lvalp = (unsigned long)val;
}
*valp = tmp;
}
return 0;
}
@ -2717,22 +2710,22 @@ static int do_proc_douintvec_minmax_conv(unsigned long *lvalp,
unsigned int *valp,
int write, void *data)
{
int ret;
unsigned int tmp;
struct do_proc_douintvec_minmax_conv_param *param = data;
/* write via temporary local uint for bounds-checking */
unsigned int *up = write ? &tmp : valp;
ret = do_proc_douintvec_conv(lvalp, up, write, data);
if (ret)
return ret;
if (write) {
unsigned int val = *lvalp;
if (*lvalp > UINT_MAX)
return -EINVAL;
if ((param->min && *param->min > val) ||
(param->max && *param->max < val))
if ((param->min && *param->min > tmp) ||
(param->max && *param->max < tmp))
return -ERANGE;
*valp = val;
} else {
unsigned int val = *valp;
*lvalp = (unsigned long) val;
*valp = tmp;
}
return 0;