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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 20:51:44 +00:00
parent 9f64e10225
commit 558ff41f27
2 changed files with 28 additions and 8 deletions
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12
src/backend/utils/hash/dynahash.c
View File

@@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.58 2004/12/31 22:01:37 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/utils/hash/dynahash.c,v 1.58.4.1 2005/06/18 20:51:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -143,6 +143,14 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags)
else
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)
{
/*
@@ -657,7 +665,7 @@ hash_search(HTAB *hashp,
/* copy key into record */
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 */

22
src/include/utils/hsearch.h
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.34 2004/12/31 22:03:46 pgsql Exp $
* $PostgreSQL: pgsql/src/include/utils/hsearch.h,v 1.34.4.1 2005/06/18 20:51:44 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -16,15 +16,26 @@
/*
* Hash and comparison functions must have these signatures. Comparison
* functions return zero for match, nonzero for no match. (The comparison
* function definition is designed to allow memcmp() and strncmp() to be
* used directly as key comparison functions.)
* Hash functions must have this signature.
*/
typedef uint32 (*HashValueFunc) (const void *key, Size keysize);
/*
* Key comparison functions must have this signature. Comparison functions
* return zero for match, nonzero for no match. (The comparison function
* definition is designed to allow memcmp() and strncmp() to be used directly
* as key comparison functions.)
*/
typedef int (*HashCompareFunc) (const void *key1, const void *key2,
Size keysize);
/*
* Key copying functions must have this signature. The return value is not
* used. (The definition is set up to allow memcpy() and strncpy() to be
* used directly.)
*/
typedef void *(*HashCopyFunc) (void *dest, const void *src, Size keysize);
/*
* Space allocation function for a hashtable --- designed to match malloc().
* Note: there is no free function API; can't destroy a hashtable unless you
@@ -108,6 +119,7 @@ typedef struct HTAB
* used */
char *tabname; /* table name (for error messages) */
bool isshared; /* true if table is in shared memory */
HashCopyFunc keycopy; /* key copying function */
} HTAB;
/* Parameter data structure for hash_create */