netdev - [iproute PATCH v3 1/7] ipntable: Avoid memory allocation for filter.name

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Date:   Mon, 21 Aug 2017 15:23:35 +0200
From:   Phil Sutter <phil@....cc>
To:     Stephen Hemminger <stephen@...workplumber.org>
Cc:     netdev@...r.kernel.org
Subject: [iproute PATCH v3 1/7] ipntable: Avoid memory allocation for filter.name

The original issue was that filter.name might end up unterminated if
user provided string was too long. But in fact it is not necessary to
copy the commandline parameter at all: just make filter.name point to it
instead.

Signed-off-by: Phil Sutter <phil@....cc>
---
 ip/ipntable.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ip/ipntable.c b/ip/ipntable.c
index 879626ee4f491..e0bd9b6ebd155 100644
--- a/ip/ipntable.c
+++ b/ip/ipntable.c
@@ -37,7 +37,7 @@ static struct
 	int family;
 	int index;
 #define NONE_DEV	(-1)
-	char name[1024];
+	const char *name;
 } filter;
 
 static void usage(void) __attribute__((noreturn));
@@ -369,7 +369,7 @@ static int print_ntable(const struct sockaddr_nl *who, struct nlmsghdr *n, void
 	if (tb[NDTA_NAME]) {
 		const char *name = rta_getattr_str(tb[NDTA_NAME]);
 
-		if (strlen(filter.name) > 0 && strcmp(filter.name, name))
+		if (filter.name && strcmp(filter.name, name))
 			return 0;
 	}
 	if (tb[NDTA_PARMS]) {
@@ -633,7 +633,7 @@ static int ipntable_show(int argc, char **argv)
 		} else if (strcmp(*argv, "name") == 0) {
 			NEXT_ARG();
 
-			strncpy(filter.name, *argv, sizeof(filter.name));
+			filter.name = *argv;
 		} else
 			invarg("unknown", *argv);
 
-- 
2.13.1