* [PATCH] Truncate MCAST_GRP_NAME and FAMILY_NAME char arrays as C strings
@ 2013-03-19 12:27 Masatake YAMATO
0 siblings, 0 replies; only message in thread
From: Masatake YAMATO @ 2013-03-19 12:27 UTC (permalink / raw)
To: netdev; +Cc: Masatake YAMATO
This is a patch for genl command in iproute2.
You will see garbage at the end of line in the output of following command line:
$ genl ctrl show | grep thermal_mc_group
#1: ID-0x2 name: thermal_mc_group^B
The type of structure field for "name" is char[16] in kernel:
#define GENL_NAMSIZ 16 /* length of family name */
...
struct genl_multicast_group {
...
char name[GENL_NAMSIZ];
...
};
strlen("thermal_mc_group") == 16 is too long for the array size.
This patch protects genl process from this kind of bug by putting
nul char at the end of array after receiving a message from the
kernel.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
---
genl/ctrl.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/genl/ctrl.c b/genl/ctrl.c
index 7c42578..fd5a50a 100644
--- a/genl/ctrl.c
+++ b/genl/ctrl.c
@@ -168,6 +168,7 @@ static int print_ctrl_grp(FILE *fp, struct rtattr *arg, __u32 ctrl_ver)
}
if (tb[1]) {
char *name = RTA_DATA(tb[CTRL_ATTR_MCAST_GRP_NAME]);
+ name[GENL_NAMSIZ - 1] = '\0';
fprintf(fp, " name: %s ", name);
}
return 0;
@@ -214,6 +215,7 @@ static int print_ctrl(const struct sockaddr_nl *who, struct nlmsghdr *n,
if (tb[CTRL_ATTR_FAMILY_NAME]) {
char *name = RTA_DATA(tb[CTRL_ATTR_FAMILY_NAME]);
+ name[GENL_NAMSIZ - 1] = '\0';
fprintf(fp, "\nName: %s\n",name);
}
if (tb[CTRL_ATTR_FAMILY_ID]) {
--
1.7.11.7
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2013-03-19 12:27 [PATCH] Truncate MCAST_GRP_NAME and FAMILY_NAME char arrays as C strings Masatake YAMATO
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