diff options
Diffstat (limited to 'sys/netlink/netlink_message_parser.c')
| -rw-r--r-- | sys/netlink/netlink_message_parser.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/sys/netlink/netlink_message_parser.c b/sys/netlink/netlink_message_parser.c index 4c41235efaac..54aceb660a98 100644 --- a/sys/netlink/netlink_message_parser.c +++ b/sys/netlink/netlink_message_parser.c @@ -50,6 +50,38 @@ #include <netlink/netlink_debug.h> _DECLARE_DEBUG(LOG_INFO); +/* + * Some applications try to provide only the non-zero part of the required + * message header instead of a full one. It happens when fetching routes or + * interface addresses, where the first header byte is the family. + * This behavior is "illegal" under the "strict" Netlink socket option, however + * there are many applications out there doing things in the "old" way. + * Support this usecase by copying the provided bytes into the temporary + * zero-filled header and running the parser on this header instead. + */ +struct nlmsghdr * +nl_alloc_compat_hdr(struct nlmsghdr *hdr, uint32_t len, struct nl_pstate *npt) +{ + struct nlmsghdr *tmp; + + MPASS(hdr->nlmsg_len < sizeof(struct nlmsghdr) + len); + + len += sizeof(struct nlmsghdr); + if (npt->strict) { + nlmsg_report_err_msg(npt, + "header too short: expected %d, got %d", + len, hdr->nlmsg_len); + return (NULL); + } + tmp = npt_alloc(npt, len); + if (tmp == NULL) + return (NULL); + memcpy(tmp, hdr, hdr->nlmsg_len); + tmp->nlmsg_len = len; + + return (tmp); +} + bool nlmsg_report_err_msg(struct nl_pstate *npt, const char *fmt, ...) { |