package/utils/busybox/patches/302-netlink-alignment.patch

   1 From a843f09a4d4428cf11ca02307e60058251b05743 Mon Sep 17 00:00:00 2001
   2 From: Hauke Mehrtens <hauke@hauke-m.de>
   3 Date: Fri, 16 Sep 2016 21:52:03 +0200
   4 Subject: [PATCH] libnetlink: fix alignment of netlink messages
   5
   6 An padding to align a message should not only be added between
   7 different attributes of a netlink message, but also at the end of the
   8 message to pad it to the correct size.
   9
  10 Without this patch the following command does not work and returns an
  11 error code:
  12 ip link add type nlmon
  13
  14 Without this ip from busybox sends this:
  15 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
  16 return value: 2
  17
  18 The normal ip utile from iproute2 sends this:
  19 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
  20 return value: 0
  21
  22 With this patch ip from busybox sends this:
  23 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
  24 return value: 0
  25
  26 Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
  27 ---
  28  networking/libiproute/libnetlink.c | 16 ++++++++--------
  29  1 file changed, 8 insertions(+), 8 deletions(-)
  30
  31 --- a/networking/libiproute/libnetlink.c
  32 +++ b/networking/libiproute/libnetlink.c
  33 @@ -338,14 +338,14 @@ int FAST_FUNC addattr32(struct nlmsghdr
  34         int len = RTA_LENGTH(4);
  35         struct rtattr *rta;
  36
  37 -       if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
  38 +       if ((int)(NLMSG_ALIGN(n->nlmsg_len + len)) > maxlen) {
  39                 return -1;
  40         }
  41         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
  42         rta->rta_type = type;
  43         rta->rta_len = len;
  44         move_to_unaligned32(RTA_DATA(rta), data);
  45 -       n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
  46 +       n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len + len);
  47         return 0;
  48  }
  49
  50 @@ -354,14 +354,14 @@ int FAST_FUNC addattr_l(struct nlmsghdr
  51         int len = RTA_LENGTH(alen);
  52         struct rtattr *rta;
  53
  54 -       if ((int)(NLMSG_ALIGN(n->nlmsg_len) + len) > maxlen) {
  55 +       if ((int)(NLMSG_ALIGN(n->nlmsg_len + len)) > maxlen) {
  56                 return -1;
  57         }
  58         rta = (struct rtattr*)(((char*)n) + NLMSG_ALIGN(n->nlmsg_len));
  59         rta->rta_type = type;
  60         rta->rta_len = len;
  61         memcpy(RTA_DATA(rta), data, alen);
  62 -       n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + len;
  63 +       n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len + len);
  64         return 0;
  65  }
  66
  67 @@ -370,14 +370,14 @@ int FAST_FUNC rta_addattr32(struct rtatt
  68         int len = RTA_LENGTH(4);
  69         struct rtattr *subrta;
  70
  71 -       if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
  72 +       if (RTA_ALIGN(rta->rta_len + len) > maxlen) {
  73                 return -1;
  74         }
  75         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
  76         subrta->rta_type = type;
  77         subrta->rta_len = len;
  78         move_to_unaligned32(RTA_DATA(subrta), data);
  79 -       rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
  80 +       rta->rta_len = NLMSG_ALIGN(rta->rta_len + len);
  81         return 0;
  82  }
  83
  84 @@ -386,14 +386,14 @@ int FAST_FUNC rta_addattr_l(struct rtatt
  85         struct rtattr *subrta;
  86         int len = RTA_LENGTH(alen);
  87
  88 -       if (RTA_ALIGN(rta->rta_len) + len > maxlen) {
  89 +       if (RTA_ALIGN(rta->rta_len + len) > maxlen) {
  90                 return -1;
  91         }
  92         subrta = (struct rtattr*)(((char*)rta) + RTA_ALIGN(rta->rta_len));
  93         subrta->rta_type = type;
  94         subrta->rta_len = len;
  95         memcpy(RTA_DATA(subrta), data, alen);
  96 -       rta->rta_len = NLMSG_ALIGN(rta->rta_len) + len;
  97 +       rta->rta_len = NLMSG_ALIGN(rta->rta_len + len);
  98         return 0;
  99  }
 100