diff options
Diffstat (limited to 'src/backend/lib/stringinfo.c')
| -rw-r--r-- | src/backend/lib/stringinfo.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/src/backend/lib/stringinfo.c b/src/backend/lib/stringinfo.c index 26fdbc8e488..4ca8ffeaa99 100644 --- a/src/backend/lib/stringinfo.c +++ b/src/backend/lib/stringinfo.c @@ -9,13 +9,14 @@ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.37 2003/11/29 22:39:42 pgsql Exp $ + * $PostgreSQL: pgsql/src/backend/lib/stringinfo.c,v 1.38 2004/05/11 20:07:26 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include "lib/stringinfo.h" +#include "utils/memutils.h" /* @@ -220,7 +221,20 @@ enlargeStringInfo(StringInfo str, int needed) { int newlen; + /* + * Guard against ridiculous "needed" values, which can occur if we're + * fed bogus data. Without this, we can get an overflow or infinite + * loop in the following. + */ + if (needed < 0 || + ((Size) needed) >= (MaxAllocSize - (Size) str->len)) + elog(ERROR, "invalid string enlargement request size %d", + needed); + needed += str->len + 1; /* total space required now */ + + /* Because of the above test, we now have needed <= MaxAllocSize */ + if (needed <= str->maxlen) return; /* got enough space already */ @@ -234,6 +248,14 @@ enlargeStringInfo(StringInfo str, int needed) while (needed > newlen) newlen = 2 * newlen; + /* + * Clamp to MaxAllocSize in case we went past it. Note we are assuming + * here that MaxAllocSize <= INT_MAX/2, else the above loop could + * overflow. We will still have newlen >= needed. + */ + if (newlen > (int) MaxAllocSize) + newlen = (int) MaxAllocSize; + str->data = (char *) repalloc(str->data, newlen); str->maxlen = newlen; |