diff options
| author | Jakub Kicinski <kuba@kernel.org> | 2022-08-24 17:18:30 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-08-29 12:47:15 +0100 |
| commit | 9c5d03d362519f36cd551aec596388f895c93d2d (patch) | |
| tree | 5669b75a062436435dc9d4354c668d0f61b7146c /net/netlink | |
| parent | 53a406803ca5b0b1f91beffacad4321fae4fa2a7 (diff) | |
genetlink: start to validate reserved header bytes
We had historically not checked that genlmsghdr.reserved
is 0 on input which prevents us from using those precious
bytes in the future.
One use case would be to extend the cmd field, which is
currently just 8 bits wide and 256 is not a lot of commands
for some core families.
To make sure that new families do the right thing by default
put the onus of opting out of validation on existing families.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com> (NetLabel)
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink')
| -rw-r--r-- | net/netlink/genetlink.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 76aed0571e3a..7c136de117eb 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -757,6 +757,9 @@ 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) + return -EINVAL; + if (genl_get_cmd(hdr->cmd, family, &op)) return -EOPNOTSUPP; @@ -1348,6 +1351,7 @@ static struct genl_family genl_ctrl __ro_after_init = { .module = THIS_MODULE, .ops = genl_ctrl_ops, .n_ops = ARRAY_SIZE(genl_ctrl_ops), + .resv_start_op = CTRL_CMD_GETPOLICY + 1, .mcgrps = genl_ctrl_groups, .n_mcgrps = ARRAY_SIZE(genl_ctrl_groups), .id = GENL_ID_CTRL, |