Hello,
On 7/10/20 12:42 PM, Alice Mitchell wrote:
> This adds support for substituting in the systems machine_id as well as random generated uuid or hostname,
> and caches the results
Just curious... should the nfs.conf man page be updated to explain this new support?
steved.
> ---
> support/nfs/conffile.c | 268 +++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 257 insertions(+), 11 deletions(-)
>
> diff --git a/support/nfs/conffile.c b/support/nfs/conffile.c
> index cbeef10d..58c03911 100644
> --- a/support/nfs/conffile.c
> +++ b/support/nfs/conffile.c
> @@ -40,6 +40,7 @@
> #include <sys/stat.h>
> #include <netinet/in.h>
> #include <arpa/inet.h>
> +#include <linux/if_alg.h>
> #include <ctype.h>
> #include <fcntl.h>
> #include <stdio.h>
> @@ -110,12 +111,66 @@ struct conf_binding {
> char *tag;
> char *value;
> int is_default;
> + char *cache;
> };
>
> LIST_HEAD (conf_bindings, conf_binding) conf_bindings[256];
>
> +typedef char * (*expand_fn_t)(void);
> +struct expansion_types {
> + const char *name;
> + expand_fn_t func;
> +};
> +
> +typedef struct {
> + uint8_t bytes[16];
> +} id128_t;
> +
> +/*
> + * Application ID for use with generating a machine-id string
> + */
> +static id128_t nfs_appid = {.bytes = {0xff,0x3b,0xf0,0x0f,0x34,0xa6,0x43,0xc5, \
> + 0x93,0xdd,0x16,0xdc,0x7c,0xeb,0x88,0xc8}};
> +
> const char *modified_by = NULL;
>
> +static __inline__ char
> +hexchar(int x) {
> + static const char table[16] = "0123456789abcdef";
> + return table[x & 15];
> +}
> +
> +static __inline__ int
> +unhexchar(char h)
> +{
> + if (h >= '0' && h <= '9')
> + return h - '0';
> + if (h >= 'a' && h <= 'f')
> + return h - 'a' + 10;
> + if (h >= 'A' && h <= 'F')
> + return h - 'A' + 10;
> + return -1;
> +}
> +
> +static char *
> +tohexstr(const unsigned char *data, int len)
> +{
> + int i;
> + char *result = NULL;
> +
> + result = calloc(1, (len*2)+1);
> + if (!result) {
> + xlog(L_ERROR, "malloc error formatting string");
> + return NULL;
> + }
> +
> + for (i = 0; i < len; i++) {
> + result[i*2] = hexchar(data[i] >> 4);
> + result[i*2+1] = hexchar(data[i] & 0x0F);
> + }
> + return result;
> +}
> +
> static __inline__ uint8_t
> conf_hash(const char *s)
> {
> @@ -128,6 +183,201 @@ conf_hash(const char *s)
> return hash;
> }
>
> +static int
> +id128_from_string(const char s[], id128_t *ret)
> +{
> + id128_t t;
> + unsigned int n, i;
> + for (n=0, i=0; n<16; ) {
> + int a, b;
> + a = unhexchar(s[i++]);
> + if (a < 0)
> + return 1;
> + b = unhexchar(s[i++]);
> + if (b < 0)
> + return 1;
> +
> + t.bytes[n++] = (a << 4) | b;
> + }
> + if (s[i] != 0)
> + return 1;
> + if (ret)
> + *ret = t;
> + return 0;
> +}
> +
> +/*
> + * cryptographic hash (sha256) data into a hex encoded string
> + */
> +static char *
> +strhash(unsigned char *key, size_t keylen, unsigned char *data, size_t dlen)
> +{
> + union {
> + struct sockaddr sa;
> + struct sockaddr_alg alg;
> + } sa;
> + int sock = -1;
> + int hfd = -1;
> + uint8_t digest[129];
> + int n;
> + char *result = NULL;
> +
> + memset(&sa, 0, sizeof(sa));
> + sa.alg.salg_family = AF_ALG;
> + strcpy((char *)sa.alg.salg_type, "hash");
> + strcpy((char *)sa.alg.salg_name, "hmac(sha256)");
> +
> + sock = socket(AF_ALG, SOCK_SEQPACKET|SOCK_CLOEXEC, 0);
> + if (sock < 0) {
> + xlog(L_ERROR, "error creating socket");
> + goto cleanup;
> + }
> +
> + if (bind(sock, (struct sockaddr *)&sa.sa, sizeof(sa)) < 0) {
> + xlog(L_ERROR, "error opening khash interface");
> + goto cleanup;
> + }
> +
> + if (key && keylen > 0) {
> + if (setsockopt(sock, SOL_ALG, ALG_SET_KEY, key, keylen) < 0) {
> + xlog(L_ERROR, "Error setting key: %s", strerror(errno));
> + goto cleanup;
> + }
> + }
> +
> + hfd = accept4(sock, NULL, 0, SOCK_CLOEXEC);
> + if (hfd < 0) {
> + xlog(L_ERROR, "Error initiating khash: %s", strerror(errno));
> + goto cleanup;
> + }
> +
> + n = send(hfd, data, dlen, 0);
> + if (n < 0) {
> + xlog(L_ERROR, "Error updating khash: %s", strerror(errno));
> + goto cleanup;
> + }
> +
> + n = recv(hfd, digest, sizeof(digest), 0);
> + if (n < 0) {
> + xlog(L_ERROR, "Error fetching khash: %s", strerror(errno));
> + goto cleanup;
> + }
> +
> + result = tohexstr(digest, n);
> +cleanup:
> + if (sock != -1)
> + close(sock);
> + if (hfd != -1)
> + close(hfd);
> + if (hfd != -1)
> + close(hfd);
> +
> + return result;
> +}
> +
> +/*
> + * Read one line of content from a file
> + */
> +static char *
> +read_oneline(const char *filename)
> +{
> + char *content = conf_readfile(filename);
> + char *end;
> +
> + if (content == NULL)
> + return NULL;
> +
> + /* trim to only the first line */
> + end = strchr(content, '\n');
> + if (end != NULL)
> + *end = '\0';
> + end = strchr(content, '\r');
> + if (end != NULL)
> + *end = '\0';
> +
> + return content;
> +}
> +
> +static char *
> +expand_machine_id(void)
> +{
> + char *key = read_oneline("/etc/machine-id");
> + id128_t mid;
> + char * result = NULL;
> + size_t idlen = 0;
> +
> + if (key == NULL)
> + return NULL;
> +
> + idlen = strlen(key);
> + if (!id128_from_string(key, &mid)) {
> + result = strhash(mid.bytes, sizeof(mid), nfs_appid.bytes, sizeof(nfs_appid));
> + if (result && strlen(result) > idlen)
> + result[idlen]=0;
> + }
> + free(key);
> + return result;
> +}
> +
> +static char *
> +expand_random_uuid(void)
> +{
> + return read_oneline("/proc/sys/kernel/random/uuid");
> +}
> +
> +static char *
> +expand_hostname(void)
> +{
> + int maxlen = HOST_NAME_MAX + 1;
> + char * hostname = calloc(1, maxlen);
> +
> + if (!hostname)
> + return NULL;
> + if ((gethostname(hostname, maxlen)) == -1) {
> + free(hostname);
> + return NULL;
> + }
> + return hostname;
> +}
> +
> +static struct expansion_types var_expansions[] = {
> + { "machine_id", expand_machine_id },
> + { "machine-id", expand_machine_id },
> + { "random-uuid", expand_random_uuid },
> + { "hostname", expand_hostname },
> +};
> +
> +/* Deal with more complex variable substitutions */
> +static char *
> +expand_variable(const char *name)
> +{
> + size_t len;
> +
> + if (name == NULL || name[0] != '$')
> + return NULL;
> +
> + len = strlen(name);
> + if (name[1] == '{' && name[len-1] == '}') {
> + char *varname = strndupa(&name[2], len-3);
> +
> + for (size_t i=0; i<sizeof(var_expansions); i++) {
> + if (!strcasecmp(varname, var_expansions[i].name)) {
> + return var_expansions[i].func();
> + }
> + }
> + xlog_warn("get_conf: Unknown variable ${%s}", varname);
> + } else {
> + /* expand $name from [environment] section,
> + * or from environment
> + */
> + char *env = getenv(&name[1]);
> + if (env == NULL || *env == 0)
> + env = conf_get_section("environment", NULL, &name[1]);
> + return env;
> + }
> + return NULL;
> +}
> +
> /*
> * free all the component parts of a conf_binding struct
> */
> @@ -143,6 +393,8 @@ static void free_confbind(struct conf_binding *cb)
> free(cb->tag);
> if (cb->value)
> free(cb->value);
> + if (cb->cache)
> + free(cb->cache);
> free(cb);
> }
>
> @@ -782,7 +1034,7 @@ char *
> conf_get_section(const char *section, const char *arg, const char *tag)
> {
> struct conf_binding *cb;
> -retry:
> +
> cb = LIST_FIRST (&conf_bindings[conf_hash (section)]);
> for (; cb; cb = LIST_NEXT (cb, link)) {
> if (strcasecmp(section, cb->section) != 0)
> @@ -794,19 +1046,13 @@ retry:
> if (strcasecmp(tag, cb->tag) != 0)
> continue;
> if (cb->value[0] == '$') {
> - /* expand $name from [environment] section,
> - * or from environment
> - */
> - char *env = getenv(cb->value+1);
> - if (env && *env)
> - return env;
> - section = "environment";
> - tag = cb->value + 1;
> - goto retry;
> + if (!cb->cache)
> + cb->cache = expand_variable(cb->value);
> + return cb->cache;
> }
> return cb->value;
> }
> - return 0;
> + return NULL;
> }
>
> /*
>
