#include "cifs_spnego.h"
+#define CIFS_DEFAULT_KRB5_DIR "/tmp"
+#define CIFS_DEFAULT_KRB5_PREFIX "krb5cc_"
+
+#define MAX_CCNAME_LEN PATH_MAX + 5
+
const char *CIFSSPNEGO_VERSION = "1.3";
static const char *prog = "cifs.upcall";
typedef enum _sectype {
MS_KRB5
} sectype_t;
-/*
- * given a process ID, get the value of the KRB5CCNAME environment variable
- * in the context of that process. On error, just return NULL.
- */
-static char *
-get_krb5_ccname(pid_t pid)
+static inline int
+k5_data_equal(krb5_data d1, krb5_data d2, unsigned int length)
{
- int fd;
- ssize_t len, left;
+ if (!length)
+ length = d1.length;
- /*
- * FIXME: sysconf for ARG_MAX instead? Kernel seems to be limited to a
- * page however, so it may not matter.
- */
- char buf[4096];
- char *p, *value = NULL;
-
- buf[4095] = '\0';
- snprintf(buf, 4095, "/proc/%d/environ", pid);
- fd = open(buf, O_RDONLY);
- if (fd < 0) {
- syslog(LOG_DEBUG, "%s: unable to open %s: %d", __func__, buf,
- errno);
- return NULL;
+ return (d1.length == length &&
+ d1.length == d2.length &&
+ memcmp(d1.data, d2.data, length) == 0);
+
+}
+
+/* does the ccache have a valid TGT? */
+static time_t
+get_tgt_time(const char *ccname) {
+ krb5_context context;
+ krb5_ccache ccache;
+ krb5_cc_cursor cur;
+ krb5_creds creds;
+ krb5_principal principal;
+ krb5_data tgt = { .data = "krbtgt",
+ .length = 6 };
+ time_t credtime = 0;
+
+ if (krb5_init_context(&context)) {
+ syslog(LOG_DEBUG, "%s: unable to init krb5 context", __func__);
+ return 0;
}
- /* FIXME: don't assume that we get it all in the first read? */
- len = read(fd, buf, 4096);
- close(fd);
- if (len < 0) {
- syslog(LOG_DEBUG, "%s: unable to read from /proc/%d/environ: "
- "%d", __func__, pid, errno);
+ if (krb5_cc_resolve(context, ccname, &ccache)) {
+ syslog(LOG_DEBUG, "%s: unable to resolve krb5 cache", __func__);
+ goto err_cache;
+ }
+
+ if (krb5_cc_set_flags(context, ccache, 0)) {
+ syslog(LOG_DEBUG, "%s: unable to set flags", __func__);
+ goto err_cache;
+ }
+
+ if (krb5_cc_get_principal(context, ccache, &principal)) {
+ syslog(LOG_DEBUG, "%s: unable to get principal", __func__);
+ goto err_princ;
+ }
+
+ if (krb5_cc_start_seq_get(context, ccache, &cur)) {
+ syslog(LOG_DEBUG, "%s: unable to seq start", __func__);
+ goto err_ccstart;
+ }
+
+ while (!credtime && !krb5_cc_next_cred(context, ccache, &cur, &creds)) {
+ if (k5_data_equal(creds.server->realm, principal->realm, 0) &&
+ k5_data_equal(creds.server->data[0], tgt, tgt.length) &&
+ k5_data_equal(creds.server->data[1], principal->realm, 0) &&
+ creds.times.endtime > time(NULL))
+ credtime = creds.times.endtime;
+ krb5_free_cred_contents(context, &creds);
+ }
+ krb5_cc_end_seq_get(context, ccache, &cur);
+
+err_ccstart:
+ krb5_free_principal(context, principal);
+err_princ:
+ krb5_cc_set_flags(context, ccache, KRB5_TC_OPENCLOSE);
+ krb5_cc_close(context, ccache);
+err_cache:
+ krb5_free_context(context);
+ return credtime;
+}
+
+static int
+krb5cc_filter(const struct dirent *dirent)
+{
+ if (strstr(dirent->d_name, CIFS_DEFAULT_KRB5_PREFIX))
+ return 1;
+ else
+ return 0;
+}
+
+/* search for a credcache that looks like a likely candidate */
+static char *
+find_krb5_cc(const char *dirname, uid_t uid)
+{
+ struct dirent **namelist;
+ struct stat sbuf;
+ char ccname[MAX_CCNAME_LEN], *credpath, *best_cache = NULL;
+ int i, n;
+ time_t cred_time, best_time = 0;
+
+ n = scandir(dirname, &namelist, krb5cc_filter, NULL);
+ if (n < 0) {
+ syslog(LOG_DEBUG, "%s: scandir error on directory '%s': %s",
+ __func__, dirname, strerror(errno));
return NULL;
}
- left = len;
- p = buf;
+ for (i = 0; i < n; i++) {
+ snprintf(ccname, sizeof(ccname), "FILE:%s/%s", dirname,
+ namelist[i]->d_name);
+ credpath = ccname + 5;
+ syslog(LOG_DEBUG, "%s: considering %s", __func__, credpath);
- /* can't have valid KRB5CCNAME if there are < 13 bytes left */
- while (left > 12) {
- if (strncmp("KRB5CCNAME=", p, 11)) {
- p += strnlen(p, left);
- ++p;
- left = buf + len - p;
+ if (lstat(credpath, &sbuf)) {
+ syslog(LOG_DEBUG, "%s: stat error on '%s': %s",
+ __func__, credpath, strerror(errno));
+ free(namelist[i]);
continue;
}
- p += 11;
- left -= 11;
- value = SMB_STRNDUP(p, left);
- break;
+ if (sbuf.st_uid != uid) {
+ syslog(LOG_DEBUG, "%s: %s is owned by %u, not %u",
+ __func__, credpath, sbuf.st_uid, uid);
+ free(namelist[i]);
+ continue;
+ }
+ if (!S_ISREG(sbuf.st_mode)) {
+ syslog(LOG_DEBUG, "%s: %s is not a regular file",
+ __func__, credpath);
+ free(namelist[i]);
+ continue;
+ }
+ if (!(cred_time = get_tgt_time(ccname))) {
+ syslog(LOG_DEBUG, "%s: %s is not a valid credcache.",
+ __func__, ccname);
+ free(namelist[i]);
+ continue;
+ }
+
+ if (cred_time <= best_time) {
+ syslog(LOG_DEBUG, "%s: %s expires sooner than current "
+ "best.", __func__, ccname);
+ free(namelist[i]);
+ continue;
+ }
+
+ syslog(LOG_DEBUG, "%s: %s is valid ccache", __func__, ccname);
+ free(best_cache);
+ best_cache = SMB_STRNDUP(ccname, MAX_CCNAME_LEN);
+ best_time = cred_time;
+ free(namelist[i]);
}
- syslog(LOG_DEBUG, "%s: KRB5CCNAME=%s", __func__,
- value ? value : "(null)");
- return value;
+ free(namelist);
+
+ return best_cache;
}
/*
syslog(LOG_ERR, "setuid: %s", strerror(errno));
goto out;
}
- }
- if (have & DKD_HAVE_PID)
- ccname = get_krb5_ccname(arg.pid);
+ ccname = find_krb5_cc(CIFS_DEFAULT_KRB5_DIR, arg.uid);
+ }
host = arg.hostname;
git.samba.org / samba.git / blobdiff