Re: prevent invalidly encoded input - Mailing list pgsql-patches

Tom Lane wrote:
>
> So it looks like you need to recheck if unescape_single_char sees a
> high-bit-set char.
>
> You should take a second look at the COPY code to see if there's a
> similar case there --- I forget what it does with backslash followed
> by non-digit.
>
>

It's covered. Revised patch attached. I'll probably apply this some time
tomorrow.

cheers

andrew
Index: src/backend/commands/copy.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/commands/copy.c,v
retrieving revision 1.286
diff -c -r1.286 copy.c
*** src/backend/commands/copy.c    7 Sep 2007 20:59:26 -0000    1.286
--- src/backend/commands/copy.c    12 Sep 2007 03:21:25 -0000
***************
*** 2685,2690 ****
--- 2685,2691 ----
          char       *start_ptr;
          char       *end_ptr;
          int            input_len;
+         bool        saw_high_bit = false;

          /* Make sure space remains in fieldvals[] */
          if (fieldno >= maxfields)
***************
*** 2749,2754 ****
--- 2750,2757 ----
                                  }
                              }
                              c = val & 0377;
+                             if (IS_HIGHBIT_SET(c))
+                                 saw_high_bit = true;
                          }
                          break;
                      case 'x':
***************
*** 2772,2777 ****
--- 2775,2782 ----
                                      }
                                  }
                                  c = val & 0xff;
+                                 if (IS_HIGHBIT_SET(c))
+                                     saw_high_bit = true;
                              }
                          }
                          break;
***************
*** 2799,2805 ****
                           * literally
                           */
                  }
!             }

              /* Add c to output string */
              *output_ptr++ = c;
--- 2804,2810 ----
                           * literally
                           */
                  }
!             }

              /* Add c to output string */
              *output_ptr++ = c;
***************
*** 2808,2813 ****
--- 2813,2828 ----
          /* Terminate attribute value in output area */
          *output_ptr++ = '\0';

+         /* If we de-escaped a char with the high bit set, make sure
+          * we still have valid data for the db encoding. Avoid calling strlen
+          * here for the sake of efficiency.
+          */
+         if (saw_high_bit)
+         {
+             char *fld = fieldvals[fieldno];
+             pg_verifymbstr(fld, output_ptr - (fld + 1), false);
+         }
+
          /* Check whether raw input matched null marker */
          input_len = end_ptr - start_ptr;
          if (input_len == cstate->null_print_len &&
Index: src/backend/parser/scan.l
===================================================================
RCS file: /cvsroot/pgsql/src/backend/parser/scan.l,v
retrieving revision 1.140
diff -c -r1.140 scan.l
*** src/backend/parser/scan.l    12 Aug 2007 20:18:06 -0000    1.140
--- src/backend/parser/scan.l    12 Sep 2007 03:21:26 -0000
***************
*** 60,65 ****
--- 60,66 ----
  bool            standard_conforming_strings = false;

  static bool        warn_on_first_escape;
+ static bool     saw_high_bit = false;

  /*
   * literalbuf is used to accumulate literal values when multiple rules
***************
*** 426,431 ****
--- 427,433 ----

  {xqstart}        {
                      warn_on_first_escape = true;
+                     saw_high_bit = false;
                      SET_YYLLOC();
                      if (standard_conforming_strings)
                          BEGIN(xq);
***************
*** 435,440 ****
--- 437,443 ----
                  }
  {xestart}        {
                      warn_on_first_escape = false;
+                     saw_high_bit = false;
                      SET_YYLLOC();
                      BEGIN(xe);
                      startlit();
***************
*** 443,448 ****
--- 446,453 ----
  <xq,xe>{quotefail} {
                      yyless(1);
                      BEGIN(INITIAL);
+                     if (saw_high_bit)
+                         pg_verifymbstr(literalbuf, literallen, false);
                      yylval.str = litbufdup();
                      return SCONST;
                  }
***************
*** 469,486 ****
--- 474,497 ----
                      }
                      check_string_escape_warning(yytext[1]);
                      addlitchar(unescape_single_char(yytext[1]));
+                     if (IS_HIGHBIT_SET(literalbuf[literallen]))
+                         saw_high_bit = true;
                  }
  <xe>{xeoctesc}  {
                      unsigned char c = strtoul(yytext+1, NULL, 8);

                      check_escape_warning();
                      addlitchar(c);
+                     if (IS_HIGHBIT_SET(c))
+                         saw_high_bit = true;
                  }
  <xe>{xehexesc}  {
                      unsigned char c = strtoul(yytext+2, NULL, 16);

                      check_escape_warning();
                      addlitchar(c);
+                     if (IS_HIGHBIT_SET(c))
+                         saw_high_bit = true;
                  }
  <xq,xe>{quotecontinue} {
                      /* ignore */