[PATCH 1/1] kernel/sysctl.c: avoid overflow

[Heinrich Schuchardt]

An undetected overflow may occur in do_proc_dointvec_minmax_conv_param.

Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
---
 kernel/sysctl.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 35f0dcb..a9e7be3 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2313,7 +2313,17 @@ static int do_proc_dointvec_minmax_conv(bool *negp, 
unsigned long *lvalp,
 {
        struct do_proc_dointvec_minmax_conv_param *param = data;
        if (write) {
-               int val = *negp ? -*lvalp : *lvalp;
+               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))
                        return -EINVAL;
-- 
2.1.4