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Fix misuse of StrNCpy to copy and add null to non-null-terminated data.

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Does not work since it fetches one byte beyond the source data, and when
the phase of the moon is wrong, the source data is smack up against the
end of backend memory and you get SIGSEGV.  Don't laugh, this is a fix
for an actual user bug report.
This commit is contained in:
Tom Lane 2000-07-07 21:12:53 +00:00
parent de85dd1d51
commit 65da0d66b4
9 changed files with 56 additions and 43 deletions
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4
contrib/miscutil/misc_utils.c
View File

@ -99,9 +99,9 @@ active_listeners(text *relname)
if (relname && (VARSIZE(relname) > VARHDRSZ))
{
MemSet(listen_name, 0, NAMEDATALEN);
len = MIN(VARSIZE(relname) - VARHDRSZ, NAMEDATALEN - 1);
strncpy(listen_name, VARDATA(relname), len);
listen_name[len] = '\0';
memcpy(listen_name, VARDATA(relname), len);
ScanKeyEntryInitialize(&key, 0,
Anum_pg_listener_relname,
F_NAMEEQ,

26
src/backend/libpq/be-fsstubs.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/libpq/be-fsstubs.c,v 1.48 2000/07/03 23:09:37 wieck Exp $
* $Header: /cvsroot/pgsql/src/backend/libpq/be-fsstubs.c,v 1.49 2000/07/07 21:12:53 tgl Exp $
*
* NOTES
* This should be moved to a more appropriate place. It is here
@ -379,26 +379,23 @@ lo_import(PG_FUNCTION_ARGS)
/*
* open the file to be read in
*/
nbytes = VARSIZE(filename) - VARHDRSZ + 1;
if (nbytes > FNAME_BUFSIZE)
nbytes = FNAME_BUFSIZE;
StrNCpy(fnamebuf, VARDATA(filename), nbytes);
nbytes = VARSIZE(filename) - VARHDRSZ;
if (nbytes >= FNAME_BUFSIZE)
nbytes = FNAME_BUFSIZE-1;
memcpy(fnamebuf, VARDATA(filename), nbytes);
fnamebuf[nbytes] = '\0';
fd = PathNameOpenFile(fnamebuf, O_RDONLY | PG_BINARY, 0666);
if (fd < 0)
{ /* error */
elog(ERROR, "lo_import: can't open unix file \"%s\": %m",
fnamebuf);
}
/*
* create an inversion "object"
*/
lobj = inv_create(INV_READ | INV_WRITE);
if (lobj == NULL)
{
elog(ERROR, "lo_import: can't create inv object for \"%s\"",
fnamebuf);
}
/*
* the oid for the large object is just the oid of the relation
@ -461,18 +458,17 @@ lo_export(PG_FUNCTION_ARGS)
* 022. This code used to drop it all the way to 0, but creating
* world-writable export files doesn't seem wise.
*/
nbytes = VARSIZE(filename) - VARHDRSZ + 1;
if (nbytes > FNAME_BUFSIZE)
nbytes = FNAME_BUFSIZE;
StrNCpy(fnamebuf, VARDATA(filename), nbytes);
nbytes = VARSIZE(filename) - VARHDRSZ;
if (nbytes >= FNAME_BUFSIZE)
nbytes = FNAME_BUFSIZE-1;
memcpy(fnamebuf, VARDATA(filename), nbytes);
fnamebuf[nbytes] = '\0';
oumask = umask((mode_t) 0022);
fd = PathNameOpenFile(fnamebuf, O_CREAT | O_WRONLY | O_TRUNC | PG_BINARY, 0666);
umask(oumask);
if (fd < 0)
{ /* error */
elog(ERROR, "lo_export: can't open unix file \"%s\": %m",
fnamebuf);
}
/*
* read in from the Unix file and write to the inversion file

6
src/backend/libpq/be-pqexec.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/libpq/Attic/be-pqexec.c,v 1.35 2000/07/05 23:11:19 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/libpq/Attic/be-pqexec.c,v 1.36 2000/07/07 21:12:53 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -236,8 +236,8 @@ strmake(char *str, int len)
if (len <= 0)
len = strlen(str);
newstr = (char *) palloc((unsigned) len + 1);
StrNCpy(newstr, str, len + 1);
newstr = (char *) palloc(len + 1);
memcpy(newstr, str, len);
newstr[len] = (char) 0;
return newstr;
}

3
src/backend/port/dynloader/aix.c
View File

@ -536,7 +536,8 @@ readExports(ModulePtr mp)
* first SYMNMLEN chars and make sure we have a zero byte at
* the end.
*/
StrNCpy(tmpsym, ls->l_name, SYMNMLEN + 1);
strncpy(tmpsym, ls->l_name, SYMNMLEN);
tmpsym[SYMNMLEN] = '\0';
symname = tmpsym;
}
ep->name = strdup(symname);

5
src/backend/utils/adt/like.c
View File

@ -11,7 +11,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/like.c,v 1.36 2000/07/06 05:48:11 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/like.c,v 1.37 2000/07/07 21:12:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -48,7 +48,8 @@ fixedlen_like(char *s, text *p, int charlen)
(void) pg_mb2wchar_with_len((unsigned char *) s, sterm, charlen);
#else
sterm = (char *) palloc(charlen + 1);
StrNCpy(sterm, s, charlen + 1);
memcpy(sterm, s, charlen);
sterm[charlen] = '\0';
#endif
/*

12
src/backend/utils/adt/not_in.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/not_in.c,v 1.23 2000/06/09 01:11:09 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/Attic/not_in.c,v 1.24 2000/07/07 21:12:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -52,10 +52,12 @@ int4notin(PG_FUNCTION_ARGS)
char my_copy[NAMEDATALEN * 2 + 2];
Datum value;
strlength = VARSIZE(relation_and_attr) - VARHDRSZ + 1;
if (strlength > sizeof(my_copy))
strlength = sizeof(my_copy);
StrNCpy(my_copy, VARDATA(relation_and_attr), strlength);
/* make a null-terminated copy of text */
strlength = VARSIZE(relation_and_attr) - VARHDRSZ;
if (strlength >= sizeof(my_copy))
strlength = sizeof(my_copy)-1;
memcpy(my_copy, VARDATA(relation_and_attr), strlength);
my_copy[strlength] = '\0';
relation = (char *) strtok(my_copy, ".");
attribute = (char *) strtok(NULL, ".");

5
src/backend/utils/adt/regexp.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.32 2000/07/06 05:48:11 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.33 2000/07/07 21:12:50 tgl Exp $
*
* Alistair Crooks added the code for the regex caching
* agc - cached the regular expressions used - there's a good chance
@ -164,7 +164,8 @@ fixedlen_regexeq(char *s, text *p, int charlen, int cflags)
/* be sure sterm is null-terminated */
sterm = (char *) palloc(charlen + 1);
StrNCpy(sterm, s, charlen + 1);
memcpy(sterm, s, charlen);
sterm[charlen] = '\0';
result = RE_compile_and_execute(p, sterm, cflags);

18
src/backend/utils/adt/varchar.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/varchar.c,v 1.67 2000/07/03 23:09:53 wieck Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/varchar.c,v 1.68 2000/07/07 21:12:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -115,9 +115,11 @@ bpcharout(PG_FUNCTION_ARGS)
char *result;
int len;
/* copy and add null term */
len = VARSIZE(s) - VARHDRSZ;
result = (char *) palloc(len + 1);
StrNCpy(result, VARDATA(s), len + 1); /* copy and add null term */
memcpy(result, VARDATA(s), len);
result[len] = '\0';
#ifdef CYR_RECODE
convertstr(result, len, 1);
@ -268,8 +270,8 @@ bpchar_name(char *s)
return NULL;
len = VARSIZE(s) - VARHDRSZ;
if (len > NAMEDATALEN)
len = NAMEDATALEN;
if (len >= NAMEDATALEN)
len = NAMEDATALEN-1;
while (len > 0)
{
@ -284,7 +286,7 @@ bpchar_name(char *s)
#endif
result = (NameData *) palloc(NAMEDATALEN);
StrNCpy(NameStr(*result), VARDATA(s), NAMEDATALEN);
memcpy(NameStr(*result), VARDATA(s), len);
/* now null pad to full length... */
while (len < NAMEDATALEN)
@ -316,7 +318,7 @@ name_bpchar(NameData *s)
#endif
result = (char *) palloc(VARHDRSZ + len);
strncpy(VARDATA(result), NameStr(*s), len);
memcpy(VARDATA(result), NameStr(*s), len);
VARATT_SIZEP(result) = len + VARHDRSZ;
return result;
@ -365,9 +367,11 @@ varcharout(PG_FUNCTION_ARGS)
char *result;
int len;
/* copy and add null term */
len = VARSIZE(s) - VARHDRSZ;
result = (char *) palloc(len + 1);
StrNCpy(result, VARDATA(s), len + 1); /* copy and add null term */
memcpy(result, VARDATA(s), len);
result[len] = '\0';
#ifdef CYR_RECODE
convertstr(result, len, 1);

20
src/include/c.h
View File

@ -8,7 +8,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: c.h,v 1.75 2000/07/06 21:33:44 petere Exp $
* $Id: c.h,v 1.76 2000/07/07 21:12:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -781,11 +781,19 @@ extern int assertTest(int val);
/*
* StrNCpy
* Like standard library function strncpy(), except that result string
* is guaranteed to be null-terminated --- that is, at most N-1 bytes
* of the source string will be kept.
* Also, the macro returns no result (too hard to do that without
* evaluating the arguments multiple times, which seems worse).
* Like standard library function strncpy(), except that result string
* is guaranteed to be null-terminated --- that is, at most N-1 bytes
* of the source string will be kept.
* Also, the macro returns no result (too hard to do that without
* evaluating the arguments multiple times, which seems worse).
*
* BTW: when you need to copy a non-null-terminated string (like a text
* datum) and add a null, do not do it with StrNCpy(..., len+1). That
* might seem to work, but it fetches one byte more than there is in the
* text object. One fine day you'll have a SIGSEGV because there isn't
* another byte before the end of memory. Don't laugh, we've had real
* live bug reports from real live users over exactly this mistake.
* Do it honestly with "memcpy(dst,src,len); dst[len] = '\0';", instead.
*/
#define StrNCpy(dst,src,len) \
do \