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dfilter: More arithmetic fixes 

Fix a failed assertion with constant arithmetic expressions.

Because we do not parse constants on the lexical level it is
more complicated to handle constant expressions with unparsed
values.

We need to handle missing type information gracefully for any
kind of arithmetic expression, not just unary minus.
This commit is contained in:
João Valverde 2022-04-01 18:44:15 +01:00 committed by João Valverde
parent df5941d467
commit f0ca30b60b
2 changed files with 17 additions and 13 deletions
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19
epan/dfilter/semcheck.c
View File

@ -1017,20 +1017,9 @@ check_relation_LHS_ARITHMETIC(dfwork_t *dfw, test_op_t st_op _U_,
{
stnode_t *entity;
sttype_id_t entity_type;
test_op_t st_op_math;
LOG_NODE(st_node);
sttype_test_get(st_arg1, &st_op_math, &entity, NULL);
resolve_unparsed(dfw, entity);
/* Check if we have a unary minus with a constant. That's not valid
* on the LHS. */
if (st_op_math == OP_UNARY_MINUS && node_is_constant(entity)) {
FAIL(dfw, "Left side of %s expression must be a field or function, not %s.",
stnode_todisplay(st_node), stnode_todisplay(entity));
}
check_arithmetic_operation(dfw, st_arg1, FT_NONE);
sttype_test_get(st_arg1, NULL, &entity, NULL);
@ -1441,6 +1430,12 @@ check_arithmetic_operation(dfwork_t *dfw, stnode_t *st_node, ftenum_t lhs_ftype)
FtypeCanFunc can_func = NULL;
sttype_test_get(st_node, &st_op, &st_arg1, &st_arg2);
resolve_unparsed(dfw, st_arg1);
/* On the LHS we require a field-like value as the first term. */
if (lhs_ftype == FT_NONE && node_is_constant(st_arg1)) {
FAIL(dfw, "Constant arithmetic expression on the LHS is invalid.");
}
switch (st_op) {
case OP_UNARY_MINUS:
@ -1465,7 +1460,7 @@ check_arithmetic_operation(dfwork_t *dfw, stnode_t *st_node, ftenum_t lhs_ftype)
}
ftype1 = check_arithmetic_entity(dfw, can_func, st_op, st_node, st_arg1, FT_NONE);
ftype1 = check_arithmetic_entity(dfw, can_func, st_op, st_node, st_arg1, lhs_ftype);
ftype2 = check_arithmetic_entity(dfw, can_func, st_op, st_node, st_arg2, ftype1);
if (!compatible_ftypes(ftype1, ftype2)) {

11
test/suite_dfilter/group_syntax.py
View File

@ -182,7 +182,7 @@ class case_unary_minus(unittest.TestCase):
checkDFilterCount(dfilter, 0)
def test_unary_3(self, checkDFilterFail):
error = 'Left side of "==" expression must be a field or function'
error = 'Constant arithmetic expression on the LHS is invalid'
dfilter = "-2 == tcp.dstport"
checkDFilterFail(dfilter, error)
@ -194,6 +194,15 @@ class case_arithmetic(unittest.TestCase):
dfilter = "udp.dstport == udp.srcport + 1"
checkDFilterCount(dfilter, 2)
def test_add_2(self, checkDFilterCount):
dfilter = "udp.dstport == 66 + 1"
checkDFilterCount(dfilter, 2)
def test_add_3(self, checkDFilterFail):
error = 'Constant arithmetic expression on the LHS is invalid'
dfilter = "2 + 3 == frame.number"
checkDFilterFail(dfilter, error)
def test_sub_1(self, checkDFilterCount):
dfilter = "udp.srcport == udp.dstport - 1"
checkDFilterCount(dfilter, 2)