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    SubjectRe: [PATCH v3] hv/hv_kvp_daemon: Handle IPv4 and Ipv6 combination for keyfile format
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    > On 18-Mar-2024, at 09:51, Ani Sinha <anisinha@redhat.com> wrote:
    >
    >
    >
    >> On 18-Mar-2024, at 08:15, Shradha Gupta <shradhagupta@linux.microsoft.com> wrote:
    >>
    >> If the network configuration strings are passed as a combination of IPv and
    >> IPv6 addresses, the current KVP daemon doesnot handle it for the keyfile
    >> configuration format.
    >> With these changes, the keyfile config generation logic scans through the
    >> list twice to generate IPv4 and IPv6 sections for the configuration files
    >> to handle this support.
    >>
    >> Testcases ran:Rhel 9, Hyper-V VMs
    >> (IPv4 only, IPv6 only, IPv4 and IPv6 combination)
    >> Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
    >> ---
    >> Changes in v3
    >> * Introduced a macro for the output string size
    >> * Added cound checks and used strncpy instead of strncpy
    >> * Rearranged code to reduce total lines of code
    >> ---
    >> tools/hv/hv_kvp_daemon.c | 177 ++++++++++++++++++++++++++++++---------
    >> 1 file changed, 136 insertions(+), 41 deletions(-)
    >>
    >> diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
    >> index 318e2dad27e0..156cef99d361 100644
    >> --- a/tools/hv/hv_kvp_daemon.c
    >> +++ b/tools/hv/hv_kvp_daemon.c
    >> @@ -76,6 +76,12 @@ enum {
    >> DNS
    >> };
    >>
    >> +enum {
    >> + IPV4 = 1,
    >> + IPV6,
    >> + IP_TYPE_MAX
    >> +};
    >> +
    >> static int in_hand_shake;
    >>
    >> static char *os_name = "";
    >> @@ -102,6 +108,11 @@ static struct utsname uts_buf;
    >>
    >> #define MAX_FILE_NAME 100
    >> #define ENTRIES_PER_BLOCK 50
    >> +/*
    >> + * Change this entry if the number of addresses increases in future
    >> + */
    >> +#define MAX_IP_ENTRIES 64
    >> +#define OUTSTR_BUF_SIZE ((INET6_ADDRSTRLEN + 1) * MAX_IP_ENTRIES)
    >>
    >> struct kvp_record {
    >> char key[HV_KVP_EXCHANGE_MAX_KEY_SIZE];
    >> @@ -1171,6 +1182,18 @@ static int process_ip_string(FILE *f, char *ip_string, int type)
    >> return 0;
    >> }
    >>
    >> +int ip_version_check(const char *input_addr)
    >> +{
    >> + struct in6_addr addr;
    >> +
    >> + if (inet_pton(AF_INET, input_addr, &addr))
    >> + return IPV4;
    >> + else if (inet_pton(AF_INET6, input_addr, &addr))
    >> + return IPV6;
    >> +
    >> + return -EINVAL;
    >> +}
    >> +
    >> /*
    >> * Only IPv4 subnet strings needs to be converted to plen
    >> * For IPv6 the subnet is already privided in plen format
    >> @@ -1197,14 +1220,71 @@ static int kvp_subnet_to_plen(char *subnet_addr_str)
    >> return plen;
    >> }
    >>
    >> +static int process_dns_gateway_nm(FILE *f, char *ip_string, int type,
    >> + int ip_sec)
    >> +{
    >> + char addr[INET6_ADDRSTRLEN], *output_str;
    >> + int ip_offset = 0, error = 0, ip_ver;
    >> + char *param_name;
    >> +
    >> + memset(addr, 0, sizeof(addr));
    >
    > ^^^^^^^^^^^^^^^^^^^^^^^^
    > Is this still needed?
    >
    >> +
    >> + if (type == DNS)
    >> + param_name = "dns";
    >> + else if (type == GATEWAY)
    >> + param_name = "gateway";
    >> + else
    >> + return -EINVAL;
    >> +
    >> + output_str = (char *)calloc(OUTSTR_BUF_SIZE, sizeof(char));
    >> + if (!output_str)
    >> + return -ENOMEM;
    >> +
    >> + while (1) {
    >> + memset(addr, 0, sizeof(addr));
    >> +
    >> + if (!parse_ip_val_buffer(ip_string, &ip_offset, addr,
    >> + (MAX_IP_ADDR_SIZE * 2)))
    >> + break;
    >> +
    >> + ip_ver = ip_version_check(addr);
    >> + if (ip_ver < 0)
    >> + continue;
    >> +
    >> + if ((ip_ver == IPV4 && ip_sec == IPV4) ||
    >> + (ip_ver == IPV6 && ip_sec == IPV6)) {
    >> + /*
    >> + * do a bound check to avoid out-of bound writes
    >> + */
    >> + if ((OUTSTR_BUF_SIZE - strlen(output_str)) >
    >> + (strlen(addr) + 1)) {
    >> + strncat(output_str, addr,
    >> + OUTSTR_BUF_SIZE - strlen(output_str));
    >> + strncat(output_str, ",",
    >
    > Please see man page for strncat(). Why is the third parameter simply not strlen(addr)?

    I see what you are trying to do. You are doing a bound check here. In that case, should this be
    OUTSTR_BUF_SIZE - strlen(output_str) - 1 to accommodate the terminating NULL? Man page says

    > it will use at most n bytes from src

    So n bytes from addr and one extra at the end for NULL termination since strncat () will add a terminating NULL byte in the end.

    >
    >> + OUTSTR_BUF_SIZE - strlen(output_str));
    >
    >
    >
    >> + }
    >> + } else {
    >> + continue;
    >> + }
    >> + }
    >> +
    >> + if (strlen(output_str)) {
    >
    > Please add the comment I mentioned in the previous version as to why you are doing this.
    >
    >> + output_str[strlen(output_str) - 1] = '\0';
    >> + error = fprintf(f, "%s=%s\n", param_name, output_str);
    >> + }
    >> +
    >> + free(output_str);
    >> + return error;
    >> +}
    >> +
    >> static int process_ip_string_nm(FILE *f, char *ip_string, char *subnet,
    >> - int is_ipv6)
    >> + int ip_sec)
    >> {
    >> char addr[INET6_ADDRSTRLEN];
    >> char subnet_addr[INET6_ADDRSTRLEN];
    >> int error, i = 0;
    >> int ip_offset = 0, subnet_offset = 0;
    >> - int plen;
    >> + int plen, ip_ver;
    >>
    >> memset(addr, 0, sizeof(addr));
    >> memset(subnet_addr, 0, sizeof(subnet_addr));
    >> @@ -1216,10 +1296,16 @@ static int process_ip_string_nm(FILE *f, char *ip_string, char *subnet,
    >> subnet_addr,
    >> (MAX_IP_ADDR_SIZE *
    >> 2))) {
    >> - if (!is_ipv6)
    >> + ip_ver = ip_version_check(addr);
    >> + if (ip_ver < 0)
    >> + continue;
    >> +
    >> + if (ip_ver == IPV4 && ip_sec == IPV4)
    >> plen = kvp_subnet_to_plen((char *)subnet_addr);
    >> - else
    >> + else if (ip_ver == IPV6 && ip_sec == IPV6)
    >> plen = atoi(subnet_addr);
    >> + else
    >> + continue;
    >>
    >> if (plen < 0)
    >> return plen;
    >> @@ -1238,12 +1324,11 @@ static int process_ip_string_nm(FILE *f, char *ip_string, char *subnet,
    >>
    >> static int kvp_set_ip_info(char *if_name, struct hv_kvp_ipaddr_value *new_val)
    >> {
    >> - int error = 0;
    >> + int error = 0, ip_ver;
    >> char if_filename[PATH_MAX];
    >> char nm_filename[PATH_MAX];
    >> FILE *ifcfg_file, *nmfile;
    >> char cmd[PATH_MAX];
    >> - int is_ipv6 = 0;
    >> char *mac_addr;
    >> int str_len;
    >>
    >> @@ -1421,52 +1506,62 @@ static int kvp_set_ip_info(char *if_name, struct hv_kvp_ipaddr_value *new_val)
    >> if (error)
    >> goto setval_error;
    >>
    >> - if (new_val->addr_family & ADDR_FAMILY_IPV6) {
    >> - error = fprintf(nmfile, "\n[ipv6]\n");
    >> - if (error < 0)
    >> - goto setval_error;
    >> - is_ipv6 = 1;
    >> - } else {
    >> - error = fprintf(nmfile, "\n[ipv4]\n");
    >> - if (error < 0)
    >> - goto setval_error;
    >> - }
    >> -
    >> /*
    >> - * Now we populate the keyfile format
    >> + * The keyfile format expects the IPv6 and IPv4 configuration in
    >> + * different sections. Therefore we iterate through the list twice,
    >> + * once to populate the IPv4 section and the next time for IPv6
    >> */
    >> + ip_ver = IPV4;
    >> + do {
    >> + if (ip_ver == IPV4) {
    >> + error = fprintf(nmfile, "\n[ipv4]\n");
    >> + if (error < 0)
    >> + goto setval_error;
    >> + } else {
    >> + error = fprintf(nmfile, "\n[ipv6]\n");
    >> + if (error < 0)
    >> + goto setval_error;
    >> + }
    >>
    >> - if (new_val->dhcp_enabled) {
    >> - error = kvp_write_file(nmfile, "method", "", "auto");
    >> - if (error < 0)
    >> - goto setval_error;
    >> - } else {
    >> - error = kvp_write_file(nmfile, "method", "", "manual");
    >> + /*
    >> + * Now we populate the keyfile format
    >> + */
    >> +
    >> + if (new_val->dhcp_enabled) {
    >> + error = kvp_write_file(nmfile, "method", "", "auto");
    >> + if (error < 0)
    >> + goto setval_error;
    >> + } else {
    >> + error = kvp_write_file(nmfile, "method", "", "manual");
    >> + if (error < 0)
    >> + goto setval_error;
    >> + }
    >> +
    >> + /*
    >> + * Write the configuration for ipaddress, netmask, gateway and
    >> + * name services
    >> + */
    >> + error = process_ip_string_nm(nmfile, (char *)new_val->ip_addr,
    >> + (char *)new_val->sub_net,
    >> + ip_ver);
    >> if (error < 0)
    >> goto setval_error;
    >> - }
    >>
    >> - /*
    >> - * Write the configuration for ipaddress, netmask, gateway and
    >> - * name services
    >> - */
    >> - error = process_ip_string_nm(nmfile, (char *)new_val->ip_addr,
    >> - (char *)new_val->sub_net, is_ipv6);
    >> - if (error < 0)
    >> - goto setval_error;
    >> -
    >> - /* we do not want ipv4 addresses in ipv6 section and vice versa */
    >> - if (is_ipv6 != is_ipv4((char *)new_val->gate_way)) {
    >> - error = fprintf(nmfile, "gateway=%s\n", (char *)new_val->gate_way);
    >> + error = process_dns_gateway_nm(nmfile,
    >> + (char *)new_val->gate_way,
    >> + GATEWAY, ip_ver);
    >> if (error < 0)
    >> goto setval_error;
    >> - }
    >>
    >> - if (is_ipv6 != is_ipv4((char *)new_val->dns_addr)) {
    >> - error = fprintf(nmfile, "dns=%s\n", (char *)new_val->dns_addr);
    >> + error = process_dns_gateway_nm(nmfile,
    >> + (char *)new_val->dns_addr, DNS,
    >> + ip_ver);
    >> if (error < 0)
    >> goto setval_error;
    >> - }
    >> +
    >> + ip_ver++;
    >> + } while (ip_ver < IP_TYPE_MAX);
    >> +
    >> fclose(nmfile);
    >> fclose(ifcfg_file);
    >>
    >> --
    >> 2.34.1



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