libiberty: demangler crash with missing :? or fold expression component.

When constructing an :? or fold expression that requires a third
expression only the first and second were explicitly checked to
not be NULL. Since the third expression is also required in these
constructs it needs to be explicitly checked and rejected when missing.
Otherwise the demangler will crash once it tries to d_print the
NULL component. Added two examples to demangle-expected of strings
that would crash before this fix.

Found by American Fuzzy Lop (afl) fuzzer.

From-SVN: r242451
This commit is contained in:
Mark Wielaard 2016-11-15 19:31:59 +00:00 committed by Mark Wielaard
parent 0d0bfbf47c
commit 168126e598
3 changed files with 19 additions and 0 deletions

View File

@ -1,3 +1,10 @@
2016-11-15 Mark Wielaard <mark@klomp.org>
* cp-demangle.c (d_expression_1): Make sure third expression
exists for ?: and fold expressions.
* testsuite/demangle-expected: Add examples of strings that could
crash the demangler because of missing expression.
2016-11-14 Mark Wielaard <mark@klomp.org>
* cplus-dem.c (demangle_signature): After 'H', template function,

View File

@ -3415,6 +3415,8 @@ d_expression_1 (struct d_info *di)
first = d_expression_1 (di);
second = d_expression_1 (di);
third = d_expression_1 (di);
if (third == NULL)
return NULL;
}
else if (code[0] == 'f')
{
@ -3422,6 +3424,8 @@ d_expression_1 (struct d_info *di)
first = d_operator_name (di);
second = d_expression_1 (di);
third = d_expression_1 (di);
if (third == NULL)
return NULL;
}
else if (code[0] == 'n')
{

View File

@ -4626,3 +4626,11 @@ _$_H1R
# Could crash
_Q8ccQ4M2e.
_Q8ccQ4M2e.
# fold-expression with missing third component could crash.
_Z12binary_rightIJLi1ELi2ELi3EEEv1AIXfRplT_LiEEE
_Z12binary_rightIJLi1ELi2ELi3EEEv1AIXfRplT_LiEEE
# ?: expression with missing third component could crash.
AquT_quT_4mxautouT_4mxxx
AquT_quT_4mxautouT_4mxxx