Message-Id: <4547D425-64EF-4974-A131-56811F25B9E6@redhat.com>
Date: Wed, 6 Mar 2024 14:57:12 +0530
From: Ani Sinha <anisinha@...hat.com>
To: Shradha Gupta <shradhagupta@...ux.microsoft.com>
Cc: linux-kernel@...r.kernel.org,
 linux-hyperv@...r.kernel.org,
 "K. Y. Srinivasan" <kys@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>,
 Wei Liu <wei.liu@...nel.org>,
 Dexuan Cui <decui@...rosoft.com>,
 Long Li <longli@...rosoft.com>,
 Michael Kelley <mikelley@...rosoft.com>,
 Olaf Hering <olaf@...fle.de>,
 Shradha Gupta <shradhagupta@...rosoft.com>
Subject: Re: [PATCH] hv/hv_kvp_daemon: Handle IPv4 and Ipv6 combination for
 keyfile format



> On 01-Mar-2024, at 18:26, Shradha Gupta <shradhagupta@...ux.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.
> 
> Built-on: Rhel9
> Tested-on: Rhel9(IPv4 only, IPv6 only, IPv4 and IPv6 combination)
> Signed-off-by: Shradha Gupta <shradhagupta@...ux.microsoft.com>
> ---
> tools/hv/hv_kvp_daemon.c | 152 ++++++++++++++++++++++++++++-----------
> 1 file changed, 112 insertions(+), 40 deletions(-)
> 
> diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
> index 318e2dad27e0..7e84e40b55fb 100644
> --- a/tools/hv/hv_kvp_daemon.c
> +++ b/tools/hv/hv_kvp_daemon.c
> @@ -76,6 +76,11 @@ enum {
> DNS
> };
> 
> +enum {
> + IPV4 = 1,
> + IPV6
> +};
> +
> static int in_hand_shake;
> 
> static char *os_name = "";
> @@ -1171,6 +1176,18 @@ 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;
> + else
> + return -EINVAL;
> +}
> +
> /*
>  * Only IPv4 subnet strings needs to be converted to plen
>  * For IPv6 the subnet is already privided in plen format
> @@ -1197,14 +1214,56 @@ 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, ip_ver;
> + char *param_name;
> +
> + output_str = malloc(strlen(ip_string));
> +
> + if (!output_str)
> + return 1;
> +
> + output_str[0] = '\0';
> +
> + if (type == DNS)
> + param_name = "dns";
> + else
> + param_name = "gateway";
> +
> + while (parse_ip_val_buffer(ip_string, &ip_offset, addr,
> +   (MAX_IP_ADDR_SIZE * 2))) {
> + ip_ver = ip_version_check(addr);
> +
> + if ((ip_ver == IPV4 && ip_sec == IPV4) ||
> +    (ip_ver == IPV6 && ip_sec == IPV6)) {
> + strcat(output_str, addr);
> + strcat(output_str, ",");

We need to check if we are not going out of bounds here. So existing length of output_str + length of addr + 1 should be < strlen(ip_string) which is the length of the buffer. See parse_ip_val_buffer() how it does out of bounds check.

> + } else {
> + continue;
> + }
> + }
> +
> + if (strlen(output_str)) {
> + output_str[strlen(output_str) - 1] = '\0';
> + error = fprintf(f, "%s=%s\n", param_name, output_str);
> + if (error <  0)
> + return error;
> + }
> +
> + return 0;
> +}
> +
> 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 +1275,13 @@ 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 == 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;
> @@ -1242,8 +1304,8 @@ static int kvp_set_ip_info(char *if_name, struct hv_kvp_ipaddr_value *new_val)
> char if_filename[PATH_MAX];
> char nm_filename[PATH_MAX];
> FILE *ifcfg_file, *nmfile;
> + int ip_sections_count;
> char cmd[PATH_MAX];
> - int is_ipv6 = 0;
> char *mac_addr;
> int str_len;
> 
> @@ -1421,52 +1483,62 @@ 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_sections_count = 1;
> + do {
> + if (ip_sections_count == 1) {
> + 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_sections_count);
> 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_sections_count);
> 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_sections_count);
> if (error < 0)
> goto setval_error;
> - }
> +
> + ip_sections_count++;
> + } while (ip_sections_count <= 2);
> +
> fclose(nmfile);
> fclose(ifcfg_file);
> 
> -- 
> 2.34.1
> 

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