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Commit 63e0d61

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Neil Conway
committed
Adjust datetime parsing to be more robust. We now pass the length of the
working buffer into ParseDateTime() and reject too-long input there, rather than checking the length of the input string before calling ParseDateTime(). The old method was bogus because ParseDateTime() can use a variable amount of working space, depending on the content of the input string (e.g. how many fields need to be NUL terminated). This fixes a minor stack overrun -- I don't _think_ it's exploitable, although I won't claim to be an expert. Along the way, fix a bug reported by Mark Dilger: the working buffer allocated by interval_in() was too short, which resulted in rejecting some perfectly valid interval input values. I added a regression test for this fix.
1 parent 15e4d1e commit 63e0d61

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7 files changed

+86
-75
lines changed

7 files changed

+86
-75
lines changed

‎src/backend/utils/adt/date.c

Lines changed: 10 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/utils/adt/date.c,v 1.108 2005/05/24 02:09:45 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/utils/adt/date.c,v 1.109 2005/05/26 02:04:13 neilc Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -65,12 +65,10 @@ date_in(PG_FUNCTION_ARGS)
6565
int dterr;
6666
char *field[MAXDATEFIELDS];
6767
int ftype[MAXDATEFIELDS];
68-
char lowstr[MAXDATELEN + 1];
68+
char workbuf[MAXDATELEN + 1];
6969

70-
if (strlen(str) >= sizeof(lowstr))
71-
dterr = DTERR_BAD_FORMAT;
72-
else
73-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
70+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
71+
field, ftype, MAXDATEFIELDS, &nf);
7472
if (dterr == 0)
7573
dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tzp);
7674
if (dterr != 0)
@@ -894,15 +892,13 @@ time_in(PG_FUNCTION_ARGS)
894892
int tz;
895893
int nf;
896894
int dterr;
897-
char lowstr[MAXDATELEN + 1];
895+
char workbuf[MAXDATELEN + 1];
898896
char *field[MAXDATEFIELDS];
899897
int dtype;
900898
int ftype[MAXDATEFIELDS];
901899

902-
if (strlen(str) >= sizeof(lowstr))
903-
dterr = DTERR_BAD_FORMAT;
904-
else
905-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
900+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
901+
field, ftype, MAXDATEFIELDS, &nf);
906902
if (dterr == 0)
907903
dterr = DecodeTimeOnly(field, ftype, nf, &dtype, tm, &fsec, &tz);
908904
if (dterr != 0)
@@ -1733,15 +1729,13 @@ timetz_in(PG_FUNCTION_ARGS)
17331729
int tz;
17341730
int nf;
17351731
int dterr;
1736-
char lowstr[MAXDATELEN + 1];
1732+
char workbuf[MAXDATELEN + 1];
17371733
char *field[MAXDATEFIELDS];
17381734
int dtype;
17391735
int ftype[MAXDATEFIELDS];
17401736

1741-
if (strlen(str) >= sizeof(lowstr))
1742-
dterr = DTERR_BAD_FORMAT;
1743-
else
1744-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
1737+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
1738+
field, ftype, MAXDATEFIELDS, &nf);
17451739
if (dterr == 0)
17461740
dterr = DecodeTimeOnly(field, ftype, nf, &dtype, tm, &fsec, &tz);
17471741
if (dterr != 0)

‎src/backend/utils/adt/datetime.c

Lines changed: 47 additions & 30 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.144 2005/05/24 02:09:45 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.145 2005/05/26 02:04:13 neilc Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -699,21 +699,23 @@ TrimTrailingZeros(char *str)
699699
}
700700
}
701701

702-
703702
/* ParseDateTime()
704703
* Break string into tokens based on a date/time context.
705704
* Returns 0 if successful, DTERR code if bogus input detected.
706705
*
707706
* timestr - the input string
708-
* lowstr - workspace for field string storage (must be large enough for
709-
* a copy of the input string, including trailing null)
707+
* workbuf - workspace for field string storage. This must be
708+
* larger than the largest legal input for this datetime type --
709+
* some additional space will be needed to NUL terminate fields.
710+
* buflen - the size of workbuf
710711
* field[] - pointers to field strings are returned in this array
711712
* ftype[] - field type indicators are returned in this array
712713
* maxfields - dimensions of the above two arrays
713714
* *numfields - set to the actual number of fields detected
714715
*
715-
* The fields extracted from the input are stored as separate, null-terminated
716-
* strings in the workspace at lowstr. Any text is converted to lower case.
716+
* The fields extracted from the input are stored as separate,
717+
* null-terminated strings in the workspace at workbuf. Any text is
718+
* converted to lower case.
717719
*
718720
* Several field types are assigned:
719721
* DTK_NUMBER - digits and (possibly) a decimal point
@@ -729,12 +731,27 @@ TrimTrailingZeros(char *str)
729731
* DTK_DATE can hold Posix time zones (GMT-8)
730732
*/
731733
int
732-
ParseDateTime(const char *timestr, char *lowstr,
734+
ParseDateTime(const char *timestr, char *workbuf, size_t buflen,
733735
char **field, int *ftype, int maxfields, int *numfields)
734736
{
735737
int nf = 0;
736738
const char *cp = timestr;
737-
char *lp = lowstr;
739+
char *bufp = workbuf;
740+
const char *bufend = workbuf + buflen;
741+
742+
/*
743+
* Set the character pointed-to by "bufptr" to "newchar", and
744+
* increment "bufptr". "end" gives the end of the buffer -- we
745+
* return an error if there is no space left to append a character
746+
* to the buffer. Note that "bufptr" is evaluated twice.
747+
*/
748+
#define APPEND_CHAR(bufptr, end, newchar) \
749+
do \
750+
{ \
751+
if (((bufptr) + 1) >= (end)) \
752+
return DTERR_BAD_FORMAT; \
753+
*(bufptr)++ = newchar; \
754+
} while (0)
738755

739756
/* outer loop through fields */
740757
while (*cp != '\0')
@@ -749,37 +766,37 @@ ParseDateTime(const char *timestr, char *lowstr,
749766
/* Record start of current field */
750767
if (nf >= maxfields)
751768
return DTERR_BAD_FORMAT;
752-
field[nf] = lp;
769+
field[nf] = bufp;
753770

754771
/* leading digit? then date or time */
755772
if (isdigit((unsigned char) *cp))
756773
{
757-
*lp++ = *cp++;
774+
APPEND_CHAR(bufp, bufend, *cp++);
758775
while (isdigit((unsigned char) *cp))
759-
*lp++ = *cp++;
776+
APPEND_CHAR(bufp, bufend, *cp++);
760777

761778
/* time field? */
762779
if (*cp == ':')
763780
{
764781
ftype[nf] = DTK_TIME;
765-
*lp++ = *cp++;
782+
APPEND_CHAR(bufp, bufend, *cp++);
766783
while (isdigit((unsigned char) *cp) ||
767784
(*cp == ':') || (*cp == '.'))
768-
*lp++ = *cp++;
785+
APPEND_CHAR(bufp, bufend, *cp++);
769786
}
770787
/* date field? allow embedded text month */
771788
else if (*cp == '-' || *cp == '/' || *cp == '.')
772789
{
773790
/* save delimiting character to use later */
774791
char delim = *cp;
775792

776-
*lp++ = *cp++;
793+
APPEND_CHAR(bufp, bufend, *cp++);
777794
/* second field is all digits? then no embedded text month */
778795
if (isdigit((unsigned char) *cp))
779796
{
780797
ftype[nf] = ((delim == '.') ? DTK_NUMBER : DTK_DATE);
781798
while (isdigit((unsigned char) *cp))
782-
*lp++ = *cp++;
799+
APPEND_CHAR(bufp, bufend, *cp++);
783800

784801
/*
785802
* insist that the delimiters match to get a
@@ -788,16 +805,16 @@ ParseDateTime(const char *timestr, char *lowstr,
788805
if (*cp == delim)
789806
{
790807
ftype[nf] = DTK_DATE;
791-
*lp++ = *cp++;
808+
APPEND_CHAR(bufp, bufend, *cp++);
792809
while (isdigit((unsigned char) *cp) || *cp == delim)
793-
*lp++ = *cp++;
810+
APPEND_CHAR(bufp, bufend, *cp++);
794811
}
795812
}
796813
else
797814
{
798815
ftype[nf] = DTK_DATE;
799816
while (isalnum((unsigned char) *cp) || *cp == delim)
800-
*lp++ = pg_tolower((unsigned char) *cp++);
817+
APPEND_CHAR(bufp, bufend, pg_tolower((unsigned char) *cp++));
801818
}
802819
}
803820

@@ -811,9 +828,9 @@ ParseDateTime(const char *timestr, char *lowstr,
811828
/* Leading decimal point? Then fractional seconds... */
812829
else if (*cp == '.')
813830
{
814-
*lp++ = *cp++;
831+
APPEND_CHAR(bufp, bufend, *cp++);
815832
while (isdigit((unsigned char) *cp))
816-
*lp++ = *cp++;
833+
APPEND_CHAR(bufp, bufend, *cp++);
817834

818835
ftype[nf] = DTK_NUMBER;
819836
}
@@ -825,9 +842,9 @@ ParseDateTime(const char *timestr, char *lowstr,
825842
else if (isalpha((unsigned char) *cp))
826843
{
827844
ftype[nf] = DTK_STRING;
828-
*lp++ = pg_tolower((unsigned char) *cp++);
845+
APPEND_CHAR(bufp, bufend, pg_tolower((unsigned char) *cp++));
829846
while (isalpha((unsigned char) *cp))
830-
*lp++ = pg_tolower((unsigned char) *cp++);
847+
APPEND_CHAR(bufp, bufend, pg_tolower((unsigned char) *cp++));
831848

832849
/*
833850
* Full date string with leading text month? Could also be a
@@ -838,34 +855,34 @@ ParseDateTime(const char *timestr, char *lowstr,
838855
char delim = *cp;
839856

840857
ftype[nf] = DTK_DATE;
841-
*lp++ = *cp++;
858+
APPEND_CHAR(bufp, bufend, *cp++);
842859
while (isdigit((unsigned char) *cp) || *cp == delim)
843-
*lp++ = *cp++;
860+
APPEND_CHAR(bufp, bufend, *cp++);
844861
}
845862
}
846863
/* sign? then special or numeric timezone */
847864
else if (*cp == '+' || *cp == '-')
848865
{
849-
*lp++ = *cp++;
866+
APPEND_CHAR(bufp, bufend, *cp++);
850867
/* soak up leading whitespace */
851868
while (isspace((unsigned char) *cp))
852869
cp++;
853870
/* numeric timezone? */
854871
if (isdigit((unsigned char) *cp))
855872
{
856873
ftype[nf] = DTK_TZ;
857-
*lp++ = *cp++;
874+
APPEND_CHAR(bufp, bufend, *cp++);
858875
while (isdigit((unsigned char) *cp) ||
859876
*cp == ':' || *cp == '.')
860-
*lp++ = *cp++;
877+
APPEND_CHAR(bufp, bufend, *cp++);
861878
}
862879
/* special? */
863880
else if (isalpha((unsigned char) *cp))
864881
{
865882
ftype[nf] = DTK_SPECIAL;
866-
*lp++ = pg_tolower((unsigned char) *cp++);
883+
APPEND_CHAR(bufp, bufend, pg_tolower((unsigned char) *cp++));
867884
while (isalpha((unsigned char) *cp))
868-
*lp++ = pg_tolower((unsigned char) *cp++);
885+
APPEND_CHAR(bufp, bufend, pg_tolower((unsigned char) *cp++));
869886
}
870887
/* otherwise something wrong... */
871888
else
@@ -882,7 +899,7 @@ ParseDateTime(const char *timestr, char *lowstr,
882899
return DTERR_BAD_FORMAT;
883900

884901
/* force in a delimiter after each field */
885-
*lp++ = '\0';
902+
*bufp++ = '\0';
886903
nf++;
887904
}
888905

‎src/backend/utils/adt/nabstime.c

Lines changed: 7 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
*
1111
*
1212
* IDENTIFICATION
13-
* $PostgreSQL: pgsql/src/backend/utils/adt/nabstime.c,v 1.131 2005/05/24 02:09:45 momjian Exp $
13+
* $PostgreSQL: pgsql/src/backend/utils/adt/nabstime.c,v 1.132 2005/05/26 02:04:13 neilc Exp $
1414
*
1515
*-------------------------------------------------------------------------
1616
*/
@@ -306,15 +306,13 @@ abstimein(PG_FUNCTION_ARGS)
306306
*tm = &date;
307307
int dterr;
308308
char *field[MAXDATEFIELDS];
309-
char lowstr[MAXDATELEN + 1];
309+
char workbuf[MAXDATELEN + 1];
310310
int dtype;
311311
int nf,
312312
ftype[MAXDATEFIELDS];
313313

314-
if (strlen(str) >= sizeof(lowstr))
315-
dterr = DTERR_BAD_FORMAT;
316-
else
317-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
314+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
315+
field, ftype, MAXDATEFIELDS, &nf);
318316
if (dterr == 0)
319317
dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz);
320318
if (dterr != 0)
@@ -711,12 +709,10 @@ reltimein(PG_FUNCTION_ARGS)
711709
char *field[MAXDATEFIELDS];
712710
int nf,
713711
ftype[MAXDATEFIELDS];
714-
char lowstr[MAXDATELEN + 1];
712+
char workbuf[MAXDATELEN + 1];
715713

716-
if (strlen(str) >= sizeof(lowstr))
717-
dterr = DTERR_BAD_FORMAT;
718-
else
719-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
714+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
715+
field, ftype, MAXDATEFIELDS, &nf);
720716
if (dterr == 0)
721717
dterr = DecodeInterval(field, ftype, nf, &dtype, tm, &fsec);
722718
if (dterr != 0)

‎src/backend/utils/adt/timestamp.c

Lines changed: 10 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.123 2005/05/24 02:09:45 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.124 2005/05/26 02:04:13 neilc Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -77,12 +77,10 @@ timestamp_in(PG_FUNCTION_ARGS)
7777
int dterr;
7878
char *field[MAXDATEFIELDS];
7979
int ftype[MAXDATEFIELDS];
80-
char lowstr[MAXDATELEN + MAXDATEFIELDS];
80+
char workbuf[MAXDATELEN + MAXDATEFIELDS];
8181

82-
if (strlen(str) >= sizeof(lowstr))
83-
dterr = DTERR_BAD_FORMAT;
84-
else
85-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
82+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
83+
field, ftype, MAXDATEFIELDS, &nf);
8684
if (dterr == 0)
8785
dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz);
8886
if (dterr != 0)
@@ -317,12 +315,10 @@ timestamptz_in(PG_FUNCTION_ARGS)
317315
int dterr;
318316
char *field[MAXDATEFIELDS];
319317
int ftype[MAXDATEFIELDS];
320-
char lowstr[MAXDATELEN + MAXDATEFIELDS];
318+
char workbuf[MAXDATELEN + MAXDATEFIELDS];
321319

322-
if (strlen(str) >= sizeof(lowstr))
323-
dterr = DTERR_BAD_FORMAT;
324-
else
325-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
320+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
321+
field, ftype, MAXDATEFIELDS, &nf);
326322
if (dterr == 0)
327323
dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz);
328324
if (dterr != 0)
@@ -493,7 +489,7 @@ interval_in(PG_FUNCTION_ARGS)
493489
int dterr;
494490
char *field[MAXDATEFIELDS];
495491
int ftype[MAXDATEFIELDS];
496-
char lowstr[MAXDATELEN + MAXDATEFIELDS];
492+
char workbuf[256];
497493

498494
tm->tm_year = 0;
499495
tm->tm_mon = 0;
@@ -503,10 +499,8 @@ interval_in(PG_FUNCTION_ARGS)
503499
tm->tm_sec = 0;
504500
fsec = 0;
505501

506-
if (strlen(str) >= sizeof(lowstr))
507-
dterr = DTERR_BAD_FORMAT;
508-
else
509-
dterr = ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf);
502+
dterr = ParseDateTime(str, workbuf, sizeof(workbuf), field,
503+
ftype, MAXDATEFIELDS, &nf);
510504
if (dterr == 0)
511505
dterr = DecodeInterval(field, ftype, nf, &dtype, tm, &fsec);
512506
if (dterr != 0)

‎src/include/utils/datetime.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
1010
* Portions Copyright (c) 1994, Regents of the University of California
1111
*
12-
* $PostgreSQL: pgsql/src/include/utils/datetime.h,v 1.53 2005/05/24 04:03:01 momjian Exp $
12+
* $PostgreSQL: pgsql/src/include/utils/datetime.h,v 1.54 2005/05/26 02:04:14 neilc Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -276,7 +276,7 @@ extern void GetCurrentTimeUsec(struct pg_tm * tm, fsec_t *fsec, int *tzp);
276276
extern void j2date(int jd, int *year, int *month, int *day);
277277
extern int date2j(int year, int month, int day);
278278

279-
extern int ParseDateTime(const char *timestr, char *lowstr,
279+
extern int ParseDateTime(const char *timestr, char *workbuf, size_t buflen,
280280
char **field, int *ftype,
281281
int maxfields, int *numfields);
282282
extern int DecodeDateTime(char **field, int *ftype,

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