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When using C-string lookup keys in a dynahash.c hash table, use strncpy()

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not memcpy() to copy the offered key into the hash table during HASH_ENTER.
This avoids possible core dump if the passed key is located very near the
end of memory.  Per report from Stefan Kaltenbrunner.
This commit is contained in:
Tom Lane 2005-06-18 20:51:59 +00:00
parent 2b6dd51a5f
commit 41d28499a2
2 changed files with 13 additions and 3 deletions
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12
src/backend/utils/hash/dynahash.c
View File

@ -9,7 +9,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/hash/dynahash.c,v 1.48 2003/08/19 01:13:41 tgl Exp $ * $Header: /cvsroot/pgsql/src/backend/utils/hash/dynahash.c,v 1.48.2.1 2005/06/18 20:51:59 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -144,6 +144,14 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags)
else else
hashp->match = memcmp; hashp->match = memcmp;
/*
* Similarly, the key-copying function defaults to strncpy() or memcpy().
*/
if (hashp->hash == string_hash)
hashp->keycopy = (HashCopyFunc) strncpy;
else
hashp->keycopy = memcpy;
if (flags & HASH_SHARED_MEM) if (flags & HASH_SHARED_MEM)
{ {
/* /*
@ -644,7 +652,7 @@ hash_search(HTAB *hashp,
/* copy key into record */ /* copy key into record */
currBucket->hashvalue = hashvalue; currBucket->hashvalue = hashvalue;
memcpy(ELEMENTKEY(currBucket), keyPtr, hctl->keysize); hashp->keycopy(ELEMENTKEY(currBucket), keyPtr, hctl->keysize);
/* caller is expected to fill the data field on return */ /* caller is expected to fill the data field on return */

4
src/include/utils/hsearch.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* $Id: hsearch.h,v 1.29 2003/08/19 01:13:41 tgl Exp $ * $Id: hsearch.h,v 1.29.2.1 2005/06/18 20:51:59 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -24,6 +24,7 @@
typedef uint32 (*HashValueFunc) (const void *key, Size keysize); typedef uint32 (*HashValueFunc) (const void *key, Size keysize);
typedef int (*HashCompareFunc) (const void *key1, const void *key2, typedef int (*HashCompareFunc) (const void *key1, const void *key2,
Size keysize); Size keysize);
typedef void *(*HashCopyFunc) (void *dest, const void *src, Size keysize);
/* /*
* Space allocation function for a hashtable --- designed to match malloc(). * Space allocation function for a hashtable --- designed to match malloc().
@ -108,6 +109,7 @@ typedef struct HTAB
* used */ * used */
char *tabname; /* table name (for error messages) */ char *tabname; /* table name (for error messages) */
bool isshared; /* true if table is in shared memory */ bool isshared; /* true if table is in shared memory */
HashCopyFunc keycopy; /* key copying function */
} HTAB; } HTAB;
/* Parameter data structure for hash_create */ /* Parameter data structure for hash_create */