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authorZev Weiss <zev@bewilderbeest.net>2019-03-11 23:28:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-12 10:04:00 -0700
commit2bc4fc60fb3e1a4cae429b889720755ebe9085bb (patch)
treefc497f2eb9ef6b496742e1d698830c7e3c8e567b
parent8cf7630b29701d364f8df4a50e4f1f5e752b2778 (diff)
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>
-rw-r--r--kernel/sysctl.c59
1 files changed, 26 insertions, 33 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 0854197e0e67..e5da394d1ca3 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -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;
- if (write) {
- unsigned int val = *lvalp;
+ ret = do_proc_douintvec_conv(lvalp, up, write, data);
+ if (ret)
+ return ret;
- if (*lvalp > UINT_MAX)
- return -EINVAL;
-
- if ((param->min && *param->min > val) ||
- (param->max && *param->max < val))
+ if (write) {
+ 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;