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Submit #3112

Avoid undefined shifts in bit selector loop

Added by mmcc about 1 month ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
-
Target version:
-
Start date:
12/12/2017
Due date:
% Done:

0%


Description

Hi guys.

I fixed this issue in OpenBSD a while back, but I figured I should check and
inform the rest of the BSDs.

Shifting into or out of an int's sign bit is undefined, and this loop
deterministically and intentionally does both. The following change
was applied to OpenBSD and (IIRC) NetBSD.

Thanks for your time,
Michael McConville

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index 8145d9e052..5930a462f2 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -108,7 +108,7 @@ int
findproto(char *cp, int n)
{
struct sockaddr *sa;
- int i;
+ unsigned int i;

if (n == 0)
return -1;

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