In initialize_SSL, don't fail unnecessarily when home dir is unavailable.

Instead, just act as though the certificate file(s) are not present.
There is only one case where this need be a hard failure condition: when
sslmode is verify-ca or verify-full, not having a root cert file is an
error.  Change the logic so that we complain only in that case, and
otherwise fall through cleanly.  This is how it used to behave pre-9.0,
but my patch 4ed4b6c54e5fab24ab2624d80e26f7546edc88ad of 2010-05-26 broke
the case.  Per report from Christian Kastner.

diff --git a/src/interfaces/libpq/fe-secure.c b/src/interfaces/libpq/fe-secure.c
index 14a1dcd..eacf9c6 100644 (file)
--- a/src/interfaces/libpq/fe-secure.c
+++ b/src/interfaces/libpq/fe-secure.c
@@ -825,37 +825,37 @@ initialize_SSL(PGconn *conn)
        char            homedir[MAXPGPATH];
        char            fnbuf[MAXPGPATH];
        char            sebuf[256];
+       bool            have_homedir;
        bool            have_cert;
        EVP_PKEY   *pkey = NULL;
 
        /*
         * We'll need the home directory if any of the relevant parameters are
-        * defaulted.
+        * defaulted.  If pqGetHomeDirectory fails, act as though none of the
+        * files could be found.
         */
        if (!(conn->sslcert && strlen(conn->sslcert) > 0) ||
                !(conn->sslkey && strlen(conn->sslkey) > 0) ||
                !(conn->sslrootcert && strlen(conn->sslrootcert) > 0) ||
                !(conn->sslcrl && strlen(conn->sslcrl) > 0))
-       {
-               if (!pqGetHomeDirectory(homedir, sizeof(homedir)))
-               {
-                       printfPQExpBuffer(&conn->errorMessage,
-                                                         libpq_gettext("could not get home directory to locate client certificate files\n"));
-                       return -1;
-               }
-       }
-       else
-       {
-               homedir[0] = '\0';
-       }
+               have_homedir = pqGetHomeDirectory(homedir, sizeof(homedir));
+       else                                            /* won't need it */
+               have_homedir = false;
 
        /* Read the client certificate file */
        if (conn->sslcert && strlen(conn->sslcert) > 0)
                strncpy(fnbuf, conn->sslcert, sizeof(fnbuf));
-       else
+       else if (have_homedir)
                snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, USER_CERT_FILE);
+       else
+               fnbuf[0] = '\0';
 
-       if (stat(fnbuf, &buf) != 0)
+       if (fnbuf[0] == '\0')
+       {
+               /* no home directory, proceed without a client cert */
+               have_cert = false;
+       }
+       else if (stat(fnbuf, &buf) != 0)
        {
                /*
                 * If file is not present, just go on without a client cert; server
@@ -1001,11 +1001,13 @@ initialize_SSL(PGconn *conn)
                        strncpy(fnbuf, conn->sslkey, sizeof(fnbuf));
                }
        }
-       else
+       else if (have_homedir)
        {
                /* No PGSSLKEY specified, load default file */
                snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, USER_KEY_FILE);
        }
+       else
+               fnbuf[0] = '\0';
 
        if (have_cert && fnbuf[0] != '\0')
        {
@@ -1060,10 +1062,13 @@ initialize_SSL(PGconn *conn)
         */
        if (conn->sslrootcert && strlen(conn->sslrootcert) > 0)
                strncpy(fnbuf, conn->sslrootcert, sizeof(fnbuf));
-       else
+       else if (have_homedir)
                snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, ROOT_CERT_FILE);
+       else
+               fnbuf[0] = '\0';
 
-       if (stat(fnbuf, &buf) == 0)
+       if (fnbuf[0] != '\0' &&
+               stat(fnbuf, &buf) == 0)
        {
                X509_STORE *cvstore;
 
@@ -1082,11 +1087,14 @@ initialize_SSL(PGconn *conn)
                {
                        if (conn->sslcrl && strlen(conn->sslcrl) > 0)
                                strncpy(fnbuf, conn->sslcrl, sizeof(fnbuf));
-                       else
+                       else if (have_homedir)
                                snprintf(fnbuf, sizeof(fnbuf), "%s/%s", homedir, ROOT_CRL_FILE);
+                       else
+                               fnbuf[0] = '\0';
 
                        /* Set the flags to check against the complete CRL chain */
-                       if (X509_STORE_load_locations(cvstore, fnbuf, NULL) == 1)
+                       if (fnbuf[0] != '\0' &&
+                               X509_STORE_load_locations(cvstore, fnbuf, NULL) == 1)
                        {
                                /* OpenSSL 0.96 does not support X509_V_FLAG_CRL_CHECK */
 #ifdef X509_V_FLAG_CRL_CHECK
@@ -1116,9 +1124,19 @@ initialize_SSL(PGconn *conn)
                 */
                if (conn->sslmode[0] == 'v')    /* "verify-ca" or "verify-full" */
                {
-                       printfPQExpBuffer(&conn->errorMessage,
-                               libpq_gettext("root certificate file \"%s\" does not exist\n"
-                                                         "Either provide the file or change sslmode to disable server certificate verification.\n"), fnbuf);
+                       /*
+                        * The only way to reach here with an empty filename is if
+                        * pqGetHomeDirectory failed.  That's a sufficiently unusual case
+                        * that it seems worth having a specialized error message for it.
+                        */
+                       if (fnbuf[0] == '\0')
+                               printfPQExpBuffer(&conn->errorMessage,
+                                                                 libpq_gettext("could not get home directory to locate root certificate file\n"
+                                                                                               "Either provide the file or change sslmode to disable server certificate verification.\n"));
+                       else
+                               printfPQExpBuffer(&conn->errorMessage,
+                                                                 libpq_gettext("root certificate file \"%s\" does not exist\n"
+                                                                                               "Either provide the file or change sslmode to disable server certificate verification.\n"), fnbuf);
                        return -1;
                }
        }