From: Liping Zhang <zlpnobody@gmail.com>
Date: Fri, 7 Apr 2017 15:51:07 +0000 (+0800)
Subject: sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=425fffd886ba;p=openwrt%2Fstaging%2Fblogic.git

sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec

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 <zlpnobody@gmail.com>
Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 8cca4c7bb21f..8c8714fcb53c 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 > UINT_MAX)
+			return -EINVAL;
 		*valp = *lvalp;
 	} else {
 		unsigned int val = *valp;