diff options
Diffstat (limited to 'net/netlink/genetlink.c')
| -rw-r--r-- | net/netlink/genetlink.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 7c136de117eb..39b7c00e4cef 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -739,6 +739,36 @@ out: return err; } +static int genl_header_check(const struct genl_family *family, + struct nlmsghdr *nlh, struct genlmsghdr *hdr, + struct netlink_ext_ack *extack) +{ + u16 flags; + + /* Only for commands added after we started validating */ + if (hdr->cmd < family->resv_start_op) + return 0; + + if (hdr->reserved) { + NL_SET_ERR_MSG(extack, "genlmsghdr.reserved field is not 0"); + return -EINVAL; + } + + /* Old netlink flags have pretty loose semantics, allow only the flags + * consumed by the core where we can enforce the meaning. + */ + flags = nlh->nlmsg_flags; + if ((flags & NLM_F_DUMP) == NLM_F_DUMP) /* DUMP is 2 bits */ + flags &= ~NLM_F_DUMP; + if (flags & ~(NLM_F_REQUEST | NLM_F_ACK | NLM_F_ECHO)) { + NL_SET_ERR_MSG(extack, + "ambiguous or reserved bits set in nlmsg_flags"); + return -EINVAL; + } + + return 0; +} + static int genl_family_rcv_msg(const struct genl_family *family, struct sk_buff *skb, struct nlmsghdr *nlh, @@ -757,7 +787,7 @@ static int genl_family_rcv_msg(const struct genl_family *family, if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen)) return -EINVAL; - if (hdr->cmd >= family->resv_start_op && hdr->reserved) + if (genl_header_check(family, nlh, hdr, extack)) return -EINVAL; if (genl_get_cmd(hdr->cmd, family, &op)) |