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Guard against overflow in "left" fields of query_int and ltxtquery.

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contrib/intarray's query_int type uses an int16 field to hold the
offset from a binary operator node to its left operand.  However, it
allows the number of nodes to be as much as will fit in MaxAllocSize,
so there is a risk of overflowing int16 depending on the precise shape
of the tree.  Simple right-associative cases like "a | b | c | ..."
work fine, so we should not solve this by restricting the overall
number of nodes.  Instead add a direct test of whether each individual
offset is too large.

contrib/ltree's ltxtquery type uses essentially the same logic and
has the same 16-bit restriction.

(The core backend's tsquery.c has a variant of this logic too, but
in that case the target field is 32 bits, so it is okay so long
as varlena datums are restricted to 1GB.)

In v16 and up, these types support soft error reporting, so we have
to complicate the recursive findoprnd function's API a bit to allow
the complaint to be reported softly.  v14/v15 don't need that.

Undocumented and overcomplicated code like this makes my head hurt,
so add some comments and simplify while at it.

Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Backpatch-through: 14
Security: CVE-2026-6473
This commit is contained in:
Tom Lane 2026-05-11 05:13:49 -07:00 committed by Noah Misch
parent 47dae5e740
commit 5c1069c35b
6 changed files with 132 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

82
contrib/intarray/_int_bool.c
View file

@ -435,37 +435,77 @@ boolop(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(result);
}
static void
findoprnd(ITEM *ptr, int32 *pos)
/*
* Recursively fill the "left" fields of an ITEM array that represents
* a valid postfix tree.
*
* state: only needed for error reporting
* ptr: starting element of array
* pos: in/out argument, the array index this call is responsible to fill
*
* At exit, *pos has been decremented to point before the sub-tree whose
* top is the entry-time value of *pos.
*
* Returns true if okay, false if error (the only possible error is
* overflow of a "left" field).
*/
static bool
findoprnd(WORKSTATE *state, ITEM *ptr, int32 *pos)
{
int32 mypos;
/* since this function recurses, it could be driven to stack overflow. */
check_stack_depth();
/* get the position this call is supposed to update */
mypos = *pos;
Assert(mypos >= 0);
/* in all cases, we should decrement *pos to advance over this item */
(*pos)--;
#ifdef BS_DEBUG
elog(DEBUG3, (ptr[*pos].type == OPR) ?
"%d %c" : "%d %d", *pos, ptr[*pos].val);
elog(DEBUG3, (ptr[mypos].type == OPR) ?
"%d %c" : "%d %d", mypos, ptr[mypos].val);
#endif
if (ptr[*pos].type == VAL)
if (ptr[mypos].type == VAL)
{
ptr[*pos].left = 0;
(*pos)--;
/* base case: a VAL has no operand, so just set its left to zero */
ptr[mypos].left = 0;
}
else if (ptr[*pos].val == (int32) '!')
else if (ptr[mypos].val == (int32) '!')
{
ptr[*pos].left = -1;
(*pos)--;
findoprnd(ptr, pos);
/* unary operator, likewise easy: operand is just before it */
ptr[mypos].left = -1;
/* recurse to scan operand */
if (!findoprnd(state, ptr, pos))
return false;
}
else
{
ITEM *curitem = &ptr[*pos];
int32 tmp = *pos;
/* binary operator */
int32 delta;
(*pos)--;
findoprnd(ptr, pos);
curitem->left = *pos - tmp;
findoprnd(ptr, pos);
/* recurse to scan right operand */
if (!findoprnd(state, ptr, pos))
return false;
/* we must fill left with offset to left operand's top */
/* abs(delta) < QUERYTYPEMAXITEMS, so it can't overflow ... */
delta = *pos - mypos;
/* ... but it might be too large to fit in the 16-bit left field */
Assert(delta < 0);
if (unlikely(delta < PG_INT16_MIN))
ereturn(state->escontext, false,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("query_int expression is too complex")));
ptr[mypos].left = (int16) delta;
/* recurse to scan left operand */
if (!findoprnd(state, ptr, pos))
return false;
}
return true;
}
@ -516,6 +556,7 @@ bqarr_in(PG_FUNCTION_ARGS)
query->size = state.num;
ptr = GETQUERY(query);
/* fill the query array from the data makepol constructed */
for (i = state.num - 1; i >= 0; i--)
{
ptr[i].type = state.str->type;
@ -525,8 +566,13 @@ bqarr_in(PG_FUNCTION_ARGS)
state.str = tmp;
}
/* now fill the "left" fields */
pos = query->size - 1;
findoprnd(ptr, &pos);
if (!findoprnd(&state, ptr, &pos))
PG_RETURN_NULL();
/* if successful, findoprnd should have scanned the whole array */
Assert(pos == -1);
#ifdef BS_DEBUG
initStringInfo(&pbuf);
for (i = 0; i < query->size; i++)

3
contrib/intarray/expected/_int.out
View file

@ -398,6 +398,9 @@ SELECT '1&(2&(4&(5|!6)))'::query_int;
1 & 2 & 4 & ( 5 | !6 )
(1 row)
SELECT (SELECT '0 | ' || string_agg(i::text, ' & ')
FROM generate_series(1, 17000) AS i)::query_int;
ERROR: query_int expression is too complex
-- test non-error-throwing input
SELECT str as "query_int",
pg_input_is_valid(str,'query_int') as ok,

2
contrib/intarray/sql/_int.sql
View file

@ -74,6 +74,8 @@ SELECT '1&(2&(4&(5&6)))'::query_int;
SELECT '1&2&4&5&6'::query_int;
SELECT '1&(2&(4&(5|6)))'::query_int;
SELECT '1&(2&(4&(5|!6)))'::query_int;
SELECT (SELECT '0 | ' || string_agg(i::text, ' & ')
FROM generate_series(1, 17000) AS i)::query_int;
-- test non-error-throwing input

3
contrib/ltree/expected/ltree.out
View file

@ -1281,6 +1281,9 @@ SELECT 'tree.awdfg_qwerty'::ltree @ 'tree & aw_rw%*'::ltxtquery;
f
(1 row)
SELECT (SELECT 'a | ' || string_agg('b', ' & ')
FROM generate_series(1, 17000) AS i)::ltxtquery;
ERROR: ltxtquery is too large
--arrays
SELECT '{1.2.3}'::ltree[] @> '1.2.3.4';
?column?

73
contrib/ltree/ltxtquery_io.c
View file

@ -294,33 +294,71 @@ makepol(QPRS_STATE *state)
return END;
}
static void
findoprnd(ITEM *ptr, int32 *pos)
/*
* Recursively fill the "left" fields of an ITEM array that represents
* a valid postfix tree.
*
* state: only needed for error reporting
* ptr: starting element of array
* pos: in/out argument, the array index this call is responsible to fill
*
* At exit, *pos has been incremented to point after the sub-tree whose
* top is the entry-time value of *pos.
*
* Returns true if okay, false if error (the only possible error is
* overflow of a "left" field).
*/
static bool
findoprnd(QPRS_STATE *state, ITEM *ptr, int32 *pos)
{
int32 mypos;
/* since this function recurses, it could be driven to stack overflow. */
check_stack_depth();
if (ptr[*pos].type == VAL || ptr[*pos].type == VALTRUE)
/* get the position this call is supposed to update */
mypos = *pos;
/* in all cases, we should increment *pos to advance over this item */
(*pos)++;
if (ptr[mypos].type == VAL || ptr[mypos].type == VALTRUE)
{
ptr[*pos].left = 0;
(*pos)++;
/* base case: a VAL has no operand, so just set its left to zero */
ptr[mypos].left = 0;
}
else if (ptr[*pos].val == (int32) '!')
else if (ptr[mypos].val == (int32) '!')
{
ptr[*pos].left = 1;
(*pos)++;
findoprnd(ptr, pos);
/* unary operator, likewise easy: operand is just after it */
ptr[mypos].left = 1;
/* recurse to scan operand */
if (!findoprnd(state, ptr, pos))
return false;
}
else
{
ITEM *curitem = &ptr[*pos];
int32 tmp = *pos;
/* binary operator */
int32 delta;
(*pos)++;
findoprnd(ptr, pos);
curitem->left = *pos - tmp;
findoprnd(ptr, pos);
/* recurse to scan right operand */
if (!findoprnd(state, ptr, pos))
return false;
/* we must fill left with offset to left operand's top */
/* delta can't overflow, see LTXTQUERY_TOO_BIG ... */
delta = *pos - mypos;
/* ... but it might be too large to fit in the 16-bit left field */
Assert(delta > 0);
if (unlikely(delta > PG_INT16_MAX))
ereturn(state->escontext, false,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("ltxtquery is too large")));
ptr[mypos].left = (int16) delta;
/* recurse to scan left operand */
if (!findoprnd(state, ptr, pos))
return false;
}
return true;
}
@ -396,7 +434,10 @@ queryin(char *buf, struct Node *escontext)
/* set left operand's position for every operator */
pos = 0;
findoprnd(ptr, &pos);
if (!findoprnd(&state, ptr, &pos))
return NULL;
/* if successful, findoprnd should have scanned the whole array */
Assert(pos == state.num);
return query;
}

3
contrib/ltree/sql/ltree.sql
View file

@ -252,6 +252,9 @@ SELECT 'tree.awdfg'::ltree @ 'tree & aWdfg@'::ltxtquery;
SELECT 'tree.awdfg_qwerty'::ltree @ 'tree & aw_qw%*'::ltxtquery;
SELECT 'tree.awdfg_qwerty'::ltree @ 'tree & aw_rw%*'::ltxtquery;
SELECT (SELECT 'a | ' || string_agg('b', ' & ')
FROM generate_series(1, 17000) AS i)::ltxtquery;
--arrays
SELECT '{1.2.3}'::ltree[] @> '1.2.3.4';