kernel/sysctl.c: detect overflows when converting to int

[cascardo/linux.git] / kernel / sysctl.c

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 42b7fc2..2082b1a 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -93,11 +93,9 @@
 #include <linux/nmi.h>
 #endif
 
-
 #if defined(CONFIG_SYSCTL)
 
 /* External variables not in a header file. */
-extern int max_threads;
 extern int suid_dumpable;
 #ifdef CONFIG_COREDUMP
 extern int core_uses_pid;
@@ -710,10 +708,10 @@ static struct ctl_table kern_table[] = {
 #endif
        {
                .procname       = "threads-max",
-               .data           = &max_threads,
+               .data           = NULL,
                .maxlen         = sizeof(int),
                .mode           = 0644,
-               .proc_handler   = proc_dointvec,
+               .proc_handler   = sysctl_max_threads,
        },
        {
                .procname       = "random",
@@ -1983,7 +1981,15 @@ static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
                                 int write, void *data)
 {
        if (write) {
-               *valp = *negp ? -*lvalp : *lvalp;
+               if (*negp) {
+                       if (*lvalp > (unsigned long) INT_MAX + 1)
+                               return -EINVAL;
+                       *valp = -*lvalp;
+               } else {
+                       if (*lvalp > (unsigned long) INT_MAX)
+                               return -EINVAL;
+                       *valp = *lvalp;
+               }
        } else {
                int val = *valp;
                if (val < 0) {