From 8b5e1282509290e890b4189e7fc5fc8459b4c0d0 Mon Sep 17 00:00:00 2001 From: Hauke Mehrtens Date: Fri, 16 Sep 2016 22:44:41 +0200 Subject: [PATCH] busybox: 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 Signed-off-by: Hauke Mehrtens --- .../patches/302-netlink-alignment.patch | 100 ++++++++++++++++++ 1 file changed, 100 insertions(+) create mode 100644 package/utils/busybox/patches/302-netlink-alignment.patch diff --git a/package/utils/busybox/patches/302-netlink-alignment.patch b/package/utils/busybox/patches/302-netlink-alignment.patch new file mode 100644 index 0000000000..4cd25b1872 --- /dev/null +++ b/package/utils/busybox/patches/302-netlink-alignment.patch @@ -0,0 +1,100 @@ +From a843f09a4d4428cf11ca02307e60058251b05743 Mon Sep 17 00:00:00 2001 +From: Hauke Mehrtens +Date: Fri, 16 Sep 2016 21:52:03 +0200 +Subject: [PATCH] libnetlink: fix alignment of netlink messages + +An 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, type=0x10 /* NLMSG_??? */, flags=NLM_F_REQUEST|NLM_F_ACK|0x600, seq=1474057401, pid=0}, "\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, type=0x10 /* NLMSG_??? */, flags=NLM_F_REQUEST|NLM_F_ACK|0x600, seq=1473716938, pid=0}, "\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, type=0x10 /* NLMSG_??? */, flags=NLM_F_REQUEST|NLM_F_ACK|0x600, seq=1473716908, pid=0}, "\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 +--- + networking/libiproute/libnetlink.c | 16 ++++++++-------- + 1 file changed, 8 insertions(+), 8 deletions(-) + +--- a/networking/libiproute/libnetlink.c ++++ b/networking/libiproute/libnetlink.c +@@ -338,14 +338,14 @@ int FAST_FUNC addattr32(struct nlmsghdr + 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; + } + +@@ -354,14 +354,14 @@ int FAST_FUNC addattr_l(struct nlmsghdr + 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; + } + +@@ -370,14 +370,14 @@ int FAST_FUNC rta_addattr32(struct rtatt + 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; + } + +@@ -386,14 +386,14 @@ int FAST_FUNC rta_addattr_l(struct rtatt + 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; + } + -- 2.25.1