Un-break peer authentication.

Commit 613c6d26bd42dd8c2dd0664315be9551475b8864 sloppily replaced a
lookup of the UID obtained from getpeereid() with a lookup of the
server's own user name, thus totally destroying peer authentication.
Revert.  Per report from Christoph Berg.

In passing, make sure get_user_name() zeroes *errstr on success on
Windows as well as non-Windows.  I don't think any callers actually
depend on this ATM, but we should be consistent across platforms.

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 2a46f7b9130ba29af7968b358cbd405ed97f815f..a2f1c96b8bc69ee1b7c34448f8fa007db54b0b8f 100644 (file)
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -21,7 +21,6 @@
 #include <arpa/inet.h>
 #include <unistd.h>
 
-#include "common/username.h"
 #include "libpq/auth.h"
 #include "libpq/crypt.h"
 #include "libpq/ip.h"
@@ -1560,8 +1559,7 @@ auth_peer(hbaPort *port)
        char            ident_user[IDENT_USERNAME_MAX + 1];
        uid_t           uid;
        gid_t           gid;
-       const char *user_name;
-       char       *errstr;
+       struct passwd *pass;
 
        errno = 0;
        if (getpeereid(port->sock, &uid, &gid) != 0)
@@ -1578,15 +1576,17 @@ auth_peer(hbaPort *port)
                return STATUS_ERROR;
        }
 
-       user_name = get_user_name(&errstr);
-       if (!user_name)
+       pass = getpwuid(uid);
+
+       if (pass == NULL)
        {
-               ereport(LOG, (errmsg_internal("%s", errstr)));
-               pfree(errstr);
+               ereport(LOG,
+                               (errmsg("local user with ID %d does not exist",
+                                               (int) uid)));
                return STATUS_ERROR;
        }
 
-       strlcpy(ident_user, user_name, IDENT_USERNAME_MAX + 1);
+       strlcpy(ident_user, pass->pw_name, IDENT_USERNAME_MAX + 1);
 
        return check_usermap(port->hba->usermap, port->user_name, ident_user, false);
 }

diff --git a/src/common/username.c b/src/common/username.c
index e946972a561d2737baebb71f0ddb4dad6affaaae..24c5b476278ce2cad121a831fd73cd78f616efa6 100644 (file)
--- a/src/common/username.c
+++ b/src/common/username.c
@@ -54,6 +54,8 @@ get_user_name(char **errstr)
        static char username[256 + 1];
        DWORD           len = sizeof(username) - 1;
 
+       *errstr = NULL;
+
        if (!GetUserName(username, &len))
        {
                *errstr = psprintf(_("user name lookup failure: %s"), strerror(errno));