mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-12-03 08:00:21 +08:00
Code Issues Packages Projects Releases Wiki Activity

Fix inadequately-sized output buffer in contrib/unaccent.

Browse Source 
The output buffer size in unaccent_lexize() was calculated as input string
length times pg_database_encoding_max_length(), which effectively assumes
that replacement strings aren't more than one character.  While that was
all that we previously documented it to support, the code actually has
always allowed replacement strings of arbitrary length; so if you tried
to make use of longer strings, you were at risk of buffer overrun.  To fix,
use an expansible StringInfo buffer instead of trying to determine the
maximum space needed a-priori.

This would be a security issue if unaccent rules files could be installed
by unprivileged users; but fortunately they can't, so in the back branches
the problem can be labeled as improper configuration by a superuser.
Nonetheless, a memory stomp isn't a nice way of reacting to improper
configuration, so let's back-patch the fix.
This commit is contained in:
Tom Lane 2014-07-01 11:22:43 -04:00
parent 9f03ca9151
commit 5a421a47eb
1 changed files with 24 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
contrib/unaccent/unaccent.c
View File

@ -15,6 +15,7 @@
#include "catalog/namespace.h"
#include "commands/defrem.h"
#include "lib/stringinfo.h"
#include "tsearch/ts_cache.h"
#include "tsearch/ts_locale.h"
#include "tsearch/ts_public.h"
@ -309,9 +310,12 @@ unaccent_lexize(PG_FUNCTION_ARGS)
TrieChar *rootTrie = (TrieChar *) PG_GETARG_POINTER(0);
char *srcchar = (char *) PG_GETARG_POINTER(1);
int32 len = PG_GETARG_INT32(2);
char *srcstart = srcchar,
*trgchar = NULL;
TSLexeme *res = NULL;
char *srcstart = srcchar;
TSLexeme *res;
StringInfoData buf;
/* we allocate storage for the buffer only if needed */
buf.data = NULL;
while (len > 0)
{
@ -322,37 +326,36 @@ unaccent_lexize(PG_FUNCTION_ARGS)
&matchlen);
if (node && node->replaceTo)
{
if (!res)
if (buf.data == NULL)
{
/* allocate res only if it's needed */
res = palloc0(sizeof(TSLexeme) * 2);
res->lexeme = trgchar = palloc(len * pg_database_encoding_max_length() + 1 /* \0 */ );
res->flags = TSL_FILTER;
/* initialize buffer */
initStringInfo(&buf);
/* insert any data we already skipped over */
if (srcchar != srcstart)
{
memcpy(trgchar, srcstart, srcchar - srcstart);
trgchar += (srcchar - srcstart);
}
appendBinaryStringInfo(&buf, srcstart, srcchar - srcstart);
}
memcpy(trgchar, node->replaceTo, node->replacelen);
trgchar += node->replacelen;
appendBinaryStringInfo(&buf, node->replaceTo, node->replacelen);
}
else
{
matchlen = pg_mblen(srcchar);
if (res)
{
memcpy(trgchar, srcchar, matchlen);
trgchar += matchlen;
}
if (buf.data != NULL)
appendBinaryStringInfo(&buf, srcchar, matchlen);
}
srcchar += matchlen;
len -= matchlen;
}
if (res)
*trgchar = '\0';
/* return a result only if we made at least one substitution */
if (buf.data != NULL)
{
res = (TSLexeme *) palloc0(sizeof(TSLexeme) * 2);
res->lexeme = buf.data;
res->flags = TSL_FILTER;
}
else
res = NULL;
PG_RETURN_POINTER(res);
}