Don't putenv() a string that is allocated in a context that will go away

soon.  I suspect this explains bug #3902, though I'm still not able to
reproduce that.

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index d873e71782ac86e2ee45d93fe92665f94998da77..3c52e6d008fc5da4f0eea11b41901a3e9bce016c 100644 (file)
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -384,7 +384,6 @@ pg_GSS_recvauth(Port *port)
                                min_stat,
                                lmin_s,
                                gflags;
-       char       *kt_path;
        int                     mtype;
        int                     ret;
        StringInfoData buf;
@@ -398,11 +397,19 @@ pg_GSS_recvauth(Port *port)
                 * setenv("KRB5_KTNAME", pg_krb_server_keyfile, 0); except setenv()
                 * not always available.
                 */
-               if (!getenv("KRB5_KTNAME"))
+               if (getenv("KRB5_KTNAME") == NULL)
                {
-                       kt_path = palloc(MAXPGPATH + 13);
-                       snprintf(kt_path, MAXPGPATH + 13,
-                                        "KRB5_KTNAME=%s", pg_krb_server_keyfile);
+                       size_t  kt_len = strlen(pg_krb_server_keyfile) + 14;
+                       char   *kt_path = malloc(kt_len);
+
+                       if (!kt_path)
+                       {
+                               ereport(LOG,
+                                               (errcode(ERRCODE_OUT_OF_MEMORY),
+                                                errmsg("out of memory")));
+                               return STATUS_ERROR;
+                       }
+                       snprintf(kt_path, kt_len, "KRB5_KTNAME=%s", pg_krb_server_keyfile);
                        putenv(kt_path);
                }
        }