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authorHauke Mehrtens <hauke@hauke-m.de>2016-09-16 22:40:28 +0200
committerDenys Vlasenko <vda.linux@googlemail.com>2016-09-18 22:55:47 +0200
commit4ff86df861069e51ee796bac4e8ead942f8985f5 (patch)
treecd13a51bb4652cba3fddc3c21d1fc50debbe8e96
parent0ae0509679033c8c9b511b83027d5ef076b7bf2b (diff)
downloadbusybox-4ff86df861069e51ee796bac4e8ead942f8985f5.tar.gz
libnetlink: fix alignment of netlink messages
A padding to align a message should not only be added between different attributes of a netlink message, but also at the end of the message to pad it to the correct size. Without this patch the following command does not work and returns an error code: ip link add type nlmon Without this ip from busybox sends this: sendmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base={{len=45, ...}, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\20\0\22\0\t\0\1nlmon"}, iov_len=45}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 45 return value: 2 The normal ip utile from iproute2 sends this: sendmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base={{len=48, ...}, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\20\0\22\0\t\0\1nlmon\0\0\0"}, iov_len=48}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 48 return value: 0 With this patch ip from busybox sends this: sendmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base={{len=48, ...}, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\20\0\22\0\t\0\1nlmon\0\0\0"}, iov_len=48}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 48 return value: 0 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--networking/libiproute/libnetlink.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/networking/libiproute/libnetlink.c b/networking/libiproute/libnetlink.c
index 9d5c6416b..7e0ff1b6c 100644
--- a/networking/libiproute/libnetlink.c
+++ b/networking/libiproute/libnetlink.c
@@ -340,14 +340,14 @@ int FAST_FUNC addattr32(struct nlmsghdr *n, int maxlen, int type, uint32_t data)
int len = RTA_LENGTH(4);
struct rtattr *rta;
- if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
+ if ((int)(NLMSG_ALIGN(n->nlmsg_len + len)) > maxlen) {
return -1;
}
rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
rta->rta_type = type;
rta->rta_len = len;
move_to_unaligned32(RTA_DATA(rta), data);
- n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
+ n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len + len);
return 0;
}
@@ -356,14 +356,14 @@ int FAST_FUNC addattr_l(struct nlmsghdr *n, int maxlen, int type, void *data, in
int len = RTA_LENGTH(alen);
struct rtattr *rta;
- if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
+ if ((int)(NLMSG_ALIGN(n->nlmsg_len + len)) > maxlen) {
return -1;
}
rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
rta->rta_type = type;
rta->rta_len = len;
memcpy(RTA_DATA(rta), data, alen);
- n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
+ n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len + len);
return 0;
}
@@ -372,14 +372,14 @@ int FAST_FUNC rta_addattr32(struct rtattr *rta, int maxlen, int type, uint32_t d
int len = RTA_LENGTH(4);
struct rtattr *subrta;
- if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
+ if (RTA_ALIGN(rta->rta_len + len) > maxlen) {
return -1;
}
subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
subrta->rta_type = type;
subrta->rta_len = len;
move_to_unaligned32(RTA_DATA(subrta), data);
- rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
+ rta->rta_len = NLMSG_ALIGN(rta->rta_len + len);
return 0;
}
@@ -388,14 +388,14 @@ int FAST_FUNC rta_addattr_l(struct rtattr *rta, int maxlen, int type, void *data
struct rtattr *subrta;
int len = RTA_LENGTH(alen);
- if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
+ if (RTA_ALIGN(rta->rta_len + len) > maxlen) {
return -1;
}
subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
subrta->rta_type = type;
subrta->rta_len = len;
memcpy(RTA_DATA(subrta), data, alen);
- rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
+ rta->rta_len = NLMSG_ALIGN(rta->rta_len + len);
return 0;
}