Re: libpq: fix unlikely memory leak

Tom Lane wrote:
> Since both allocations are only transient within this routine, there's
> a simpler more effective solution, which is to only do one malloc in
> the first place

Yeah, true. Attached is a revised patch -- committed to HEAD.

-Neil
Index: src/interfaces/libpq/fe-auth.c
===================================================================
RCS file: /var/lib/cvs/pgsql/src/interfaces/libpq/fe-auth.c,v
retrieving revision 1.102
diff -c -r1.102 fe-auth.c
*** src/interfaces/libpq/fe-auth.c    27 Jun 2005 02:04:26 -0000    1.102
--- src/interfaces/libpq/fe-auth.c    30 Jun 2005 01:55:35 -0000
***************
*** 407,433 ****
              {
                  char       *crypt_pwd2;

!                 if (!(crypt_pwd = malloc(MD5_PASSWD_LEN + 1)) ||
!                     !(crypt_pwd2 = malloc(MD5_PASSWD_LEN + 1)))
                  {
                      fprintf(stderr, libpq_gettext("out of memory\n"));
                      return STATUS_ERROR;
                  }
                  if (!EncryptMD5(password, conn->pguser,
                                  strlen(conn->pguser), crypt_pwd2))
                  {
                      free(crypt_pwd);
-                     free(crypt_pwd2);
                      return STATUS_ERROR;
                  }
                  if (!EncryptMD5(crypt_pwd2 + strlen("md5"), conn->md5Salt,
                                  sizeof(conn->md5Salt), crypt_pwd))
                  {
                      free(crypt_pwd);
-                     free(crypt_pwd2);
                      return STATUS_ERROR;
                  }
-                 free(crypt_pwd2);
                  break;
              }
          case AUTH_REQ_CRYPT:
--- 407,433 ----
              {
                  char       *crypt_pwd2;

!                 /* Allocate enough space for two MD5 hashes */
!                 crypt_pwd = malloc(2 * (MD5_PASSWD_LEN + 1));
!                 if (!crypt_pwd)
                  {
                      fprintf(stderr, libpq_gettext("out of memory\n"));
                      return STATUS_ERROR;
                  }
+
+                 crypt_pwd2 = crypt_pwd + MD5_PASSWD_LEN + 1;
                  if (!EncryptMD5(password, conn->pguser,
                                  strlen(conn->pguser), crypt_pwd2))
                  {
                      free(crypt_pwd);
                      return STATUS_ERROR;
                  }
                  if (!EncryptMD5(crypt_pwd2 + strlen("md5"), conn->md5Salt,
                                  sizeof(conn->md5Salt), crypt_pwd))
                  {
                      free(crypt_pwd);
                      return STATUS_ERROR;
                  }
                  break;
              }
          case AUTH_REQ_CRYPT: