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Some security checks that we've found an external value completely

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when fetching toasted values.

Jan
This commit is contained in:
Jan Wieck 2000-07-11 12:32:03 +00:00
parent f3e5d8620c
commit 793704d71e
1 changed files with 34 additions and 2 deletions
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36
src/backend/access/heap/tuptoaster.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/heap/tuptoaster.c,v 1.6 2000/07/06 18:22:45 wieck Exp $
* $Header: /cvsroot/pgsql/src/backend/access/heap/tuptoaster.c,v 1.7 2000/07/11 12:32:03 wieck Exp $
*
*
* INTERFACE ROUTINES
@ -929,9 +929,17 @@ toast_fetch_datum(varattrib *attr)
Datum chunk;
bool isnull;
char *chunks_found;
char *chunks_expected;
ressize = attr->va_content.va_external.va_extsize;
numchunks = (ressize / TOAST_MAX_CHUNK_SIZE) + 1;
chunks_found = palloc(numchunks);
chunks_expected = palloc(numchunks);
memset(chunks_found, 0, numchunks);
memset(chunks_expected, 1, numchunks);
result = (varattrib *)palloc(ressize + VARHDRSZ);
VARATT_SIZEP(result) = ressize + VARHDRSZ;
if (VARATT_IS_COMPRESSED(attr))
@ -971,7 +979,7 @@ toast_fetch_datum(varattrib *attr)
heap_fetch(toastrel, SnapshotAny, &toasttup, &buffer);
pfree(indexRes);
if (!toasttup.t_data)
if (toasttup.t_data == NULL)
continue;
ttup = &toasttup;
@ -982,6 +990,20 @@ toast_fetch_datum(varattrib *attr)
residx = (int32)heap_getattr(ttup, 2, toasttupDesc, &isnull);
chunk = heap_getattr(ttup, 3, toasttupDesc, &isnull);
/* ----------
* Some checks on the data we've found
* ----------
*/
if (residx * TOAST_MAX_CHUNK_SIZE + VARATT_SIZE(chunk) - VARHDRSZ
> ressize)
elog(ERROR, "chunk data exceeds original data size for "
"toast value %d",
attr->va_content.va_external.va_valueid);
if (chunks_found[residx]++ > 0)
elog(ERROR, "chunk %d for toast value %d appears multiple times",
residx,
attr->va_content.va_external.va_valueid);
/* ----------
* Copy the data into our result
* ----------
@ -993,6 +1015,16 @@ toast_fetch_datum(varattrib *attr)
ReleaseBuffer(buffer);
}
/* ----------
* Final checks that we successfully fetched the datum
* ----------
*/
if (memcmp(chunks_found, chunks_expected, numchunks) != 0)
elog(ERROR, "not all toast chunks found for value %d",
attr->va_content.va_external.va_valueid);
pfree(chunks_expected);
pfree(chunks_found);
/* ----------
* End scan and close relations
* ----------