[PATCH 3/3] sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec

[Liping Zhang]

From: Liping Zhang <zlpnob...@gmail.com>

Currently, inputting the following command will succeed but actually the
value will be truncated:
  # echo 0x12ffffffff > /proc/sys/net/ipv4/tcp_notsent_lowat

This is not friendly to the user, so instead, we should report error
when the value is larger than UINT_MAX.

Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields")
Signed-off-by: Liping Zhang <zlpnob...@gmail.com>
---
 kernel/sysctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 8cca4c7..e8d1ed0 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2133,6 +2133,8 @@ static int do_proc_douintvec_conv(bool *negp, unsigned 
long *lvalp,
        if (write) {
                if (*negp)
                        return -EINVAL;
+               if (*lvalp > (unsigned long) UINT_MAX)
+                       return -EINVAL;
                *valp = *lvalp;
        } else {
                unsigned int val = *valp;
-- 
2.5.5