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Fix assorted places that need to use palloc_array().

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multirange_recv and BlockRefTableReaderNextRelation were incautious
about multiplying a possibly-large integer by a factor more than 1
and then using it as an allocation size.  This is harmless on 64-bit
systems where we'd compute a size exceeding MaxAllocSize and then
fail, but on 32-bit systems we could overflow size_t leading to an
undersized allocation and buffer overrun.

Fix these places by using palloc_array() instead of a handwritten
multiplication.  (In HEAD, some of them were fixed already, but
none of that work got back-patched at the time.)

In addition, BlockRefTableReaderNextRelation passes the same value
to BlockRefTableRead's "int length" parameter.  If built for
64-bit frontend code, palloc_array() allows a larger array size
than it otherwise would, potentially allowing that parameter to
overflow.  Add an explicit check to forestall that and keep the
behavior the same cross-platform.

Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us>
Backpatch-through: 14
Security: CVE-2026-6473
This commit is contained in:
Tom Lane 2026-05-11 05:13:48 -07:00 committed by Noah Misch
parent ebcfa7867f
commit 01b5ef7df0
2 changed files with 25 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
src/backend/utils/adt/multirangetypes.c
View file

@ -340,7 +340,7 @@ multirange_recv(PG_FUNCTION_ARGS)
Oid mltrngtypoid = PG_GETARG_OID(1);
int32 typmod = PG_GETARG_INT32(2);
MultirangeIOData *cache;
uint32 range_count;
int32 range_count;
RangeType **ranges;
MultirangeType *ret;
StringInfoData tmpbuf;
@ -348,7 +348,8 @@ multirange_recv(PG_FUNCTION_ARGS)
cache = get_multirange_io_data(fcinfo, mltrngtypoid, IOFunc_receive);
range_count = pq_getmsgint(buf, 4);
ranges = palloc(range_count * sizeof(RangeType *));
/* palloc_array will enforce a more-or-less-sane range_count value */
ranges = palloc_array(RangeType *, range_count);
initStringInfo(&tmpbuf);
for (int i = 0; i < range_count; i++)
@ -835,7 +836,7 @@ multirange_deserialize(TypeCacheEntry *rangetyp,
{
int i;
*ranges = palloc(*range_count * sizeof(RangeType *));
*ranges = palloc_array(RangeType *, *range_count);
for (i = 0; i < *range_count; i++)
(*ranges)[i] = multirange_get_range(rangetyp, multirange, i);
}
@ -999,7 +1000,7 @@ multirange_constructor2(PG_FUNCTION_ARGS)
deconstruct_array(rangeArray, rngtypid, rangetyp->typlen, rangetyp->typbyval,
rangetyp->typalign, &elements, &nulls, &range_count);
ranges = palloc0(range_count * sizeof(RangeType *));
ranges = palloc_array(RangeType *, range_count);
for (i = 0; i < range_count; i++)
{
if (nulls[i])

27
src/common/blkreftable.c
View file

@ -497,7 +497,7 @@ WriteBlockRefTable(BlockRefTable *brtab,
/* Extract entries into serializable format and sort them. */
sdata =
palloc(brtab->hash->members * sizeof(BlockRefTableSerializedEntry));
palloc_array(BlockRefTableSerializedEntry, brtab->hash->members);
blockreftable_start_iterate(brtab->hash, &it);
while ((brtentry = blockreftable_iterate(brtab->hash, &it)) != NULL)
{
@ -657,10 +657,24 @@ BlockRefTableReaderNextRelation(BlockRefTableReader *reader,
return false;
}
/*
* Sanity-check the nchunks value. In the backend, palloc_array would
* enforce this anyway (with a more generic error message); but in
* frontend it would not, potentially allowing BlockRefTableRead's length
* parameter to overflow.
*/
if (sentry.nchunks > MaxAllocSize / sizeof(uint16))
{
reader->error_callback(reader->error_callback_arg,
"file \"%s\" has oversized chunk size array",
reader->error_filename);
return false;
}
/* Read chunk size array. */
if (reader->chunk_size != NULL)
pfree(reader->chunk_size);
reader->chunk_size = palloc(sentry.nchunks * sizeof(uint16));
reader->chunk_size = palloc_array(uint16, sentry.nchunks);
BlockRefTableRead(reader, reader->chunk_size,
sentry.nchunks * sizeof(uint16));
@ -997,10 +1011,9 @@ BlockRefTableEntryMarkBlockModified(BlockRefTableEntry *entry,
if (entry->nchunks == 0)
{
entry->chunk_size = palloc0(sizeof(uint16) * max_chunks);
entry->chunk_usage = palloc0(sizeof(uint16) * max_chunks);
entry->chunk_data =
palloc0(sizeof(BlockRefTableChunk) * max_chunks);
entry->chunk_size = palloc0_array(uint16, max_chunks);
entry->chunk_usage = palloc0_array(uint16, max_chunks);
entry->chunk_data = palloc0_array(BlockRefTableChunk, max_chunks);
}
else
{
@ -1029,7 +1042,7 @@ BlockRefTableEntryMarkBlockModified(BlockRefTableEntry *entry,
if (entry->chunk_size[chunkno] == 0)
{
entry->chunk_data[chunkno] =
palloc(sizeof(uint16) * INITIAL_ENTRIES_PER_CHUNK);
palloc_array(uint16, INITIAL_ENTRIES_PER_CHUNK);
entry->chunk_size[chunkno] = INITIAL_ENTRIES_PER_CHUNK;
entry->chunk_data[chunkno][0] = chunkoffset;
entry->chunk_usage[chunkno] = 1;