From 340ce2c433b8033e57c0c23e9087ea15a349fd3e Mon Sep 17 00:00:00 2001 From: Mark Wielaard Date: Sun, 10 Jun 2018 16:59:12 +0200 Subject: [PATCH] libdw: Break long or circular DIE ref chains in dwarf_[has]attr_integrate. Bad DWARF could create a very long or circular DIE ref chain by linking DW_AT_abstract_origin or DW_AT_specification to the DIE itself. Break the chain after seeing a large number (16) of DIEs. Signed-off-by: Mark Wielaard --- libdw/ChangeLog | 6 ++++++ libdw/dwarf_attr_integrate.c | 4 ++-- libdw/dwarf_hasattr_integrate.c | 4 ++-- 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/libdw/ChangeLog b/libdw/ChangeLog index 1195cf6..07a1346 100644 --- a/libdw/ChangeLog +++ b/libdw/ChangeLog @@ -1,3 +1,9 @@ +2018-06-10 Mark Wielaard + + * dwarf_attr_integrate.c (dwarf_attr_integrate): Stop after 16 DIE + ref chains. + * dwarf_hasattr_integrate.c (dwarf_hasattr_integrate): Likewise. + 2018-06-08 Mark Wielaard * dwarf_getabbrev.c (dwarf_getabbrev): Check die and offset. diff --git a/libdw/dwarf_attr_integrate.c b/libdw/dwarf_attr_integrate.c index 748d988..fc06863 100644 --- a/libdw/dwarf_attr_integrate.c +++ b/libdw/dwarf_attr_integrate.c @@ -38,7 +38,7 @@ dwarf_attr_integrate (Dwarf_Die *die, unsigned int search_name, Dwarf_Attribute *result) { Dwarf_Die die_mem; - + int chain = 16; /* Largest DIE ref chain we will follow. */ do { Dwarf_Attribute *attr = INTUSE(dwarf_attr) (die, search_name, result); @@ -53,7 +53,7 @@ dwarf_attr_integrate (Dwarf_Die *die, unsigned int search_name, die = INTUSE(dwarf_formref_die) (attr, &die_mem); } - while (die != NULL); + while (die != NULL && chain-- != 0); /* Not NULL if it didn't have abstract_origin and specification attributes. If it is a split CU then see if the skeleton diff --git a/libdw/dwarf_hasattr_integrate.c b/libdw/dwarf_hasattr_integrate.c index 4d4b4c5..1d94628 100644 --- a/libdw/dwarf_hasattr_integrate.c +++ b/libdw/dwarf_hasattr_integrate.c @@ -37,7 +37,7 @@ int dwarf_hasattr_integrate (Dwarf_Die *die, unsigned int search_name) { Dwarf_Die die_mem; - + int chain = 16; /* Largest DIE ref chain we will follow. */ do { if (INTUSE(dwarf_hasattr) (die, search_name)) @@ -53,7 +53,7 @@ dwarf_hasattr_integrate (Dwarf_Die *die, unsigned int search_name) die = INTUSE(dwarf_formref_die) (attr, &die_mem); } - while (die != NULL); + while (die != NULL && chain-- != 0); /* Not NULL if it didn't have abstract_origin and specification attributes. If it is a split CU then see if the skeleton -- 2.7.4