diff options
| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-12-02 23:20:40 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2020-12-04 12:53:00 +0100 |
| commit | 6975c6d39366e0a086a43fa984392e2231c1b193 (patch) | |
| tree | 50677ff98632c4c160397dcd7d54d109bb0e94e5 /src | |
| parent | a8dc9e2a2b40d5d29b12920873bbe1f2cfeda8f6 (diff) | |
mnl: reply netlink error message might be larger than MNL_SOCKET_BUFFER_SIZE
Netlink attribute maximum size is 65536 bytes (given nla_len is
16-bits). NFTA_SET_ELEM_LIST_ELEMENTS stores as many set elements as
possible that can fit into this netlink attribute.
Netlink messages with NLMSG_ERROR type originating from the kernel
contain the original netlink message as payload, they might be larger
than 65536 bytes.
Add NFT_MNL_ACK_MAXSIZE which estimates the maximum Netlink header
coming as (error) reply from the kernel. This estimate is based on the
maximum netlink message size that nft sends from userspace.
Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1464
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/mnl.c | 5 |
1 files changed, 4 insertions, 1 deletions
@@ -359,6 +359,9 @@ static int mnl_batch_extack_cb(const struct nlmsghdr *nlh, void *data) } #define NFT_MNL_ECHO_RCVBUFF_DEFAULT (MNL_SOCKET_BUFFER_SIZE * 1024) +#define NFT_MNL_ACK_MAXSIZE ((sizeof(struct nlmsghdr) + \ + sizeof(struct nfgenmsg) + (1 << 16)) + \ + MNL_SOCKET_BUFFER_SIZE) int mnl_batch_talk(struct netlink_ctx *ctx, struct list_head *err_list, uint32_t num_cmds) @@ -366,7 +369,7 @@ int mnl_batch_talk(struct netlink_ctx *ctx, struct list_head *err_list, struct mnl_socket *nl = ctx->nft->nf_sock; int ret, fd = mnl_socket_get_fd(nl), portid = mnl_socket_get_portid(nl); uint32_t iov_len = nftnl_batch_iovec_len(ctx->batch); - char rcv_buf[MNL_SOCKET_BUFFER_SIZE]; + char rcv_buf[NFT_MNL_ACK_MAXSIZE]; const struct sockaddr_nl snl = { .nl_family = AF_NETLINK }; |