[COMMITTED] libdw: Check end of attributes list consistently.
Sat Aug 18 20:08:00 GMT 2018
dwarf_child (__libdw_find_attr), dwarf_getabbrevattr[_data] and
dwarf_getattrs all assume the end of the attribute list is when
both the name (code) and form of the attribute are zero.
dwarf_getabbrev (__libdw_getabbrev) and dwarf_hasattr assume the
end of the attribute list is when either the name (code) or the
form of the attribute is zero.
The DWARF spec says: "The series of attribute specifications ends
with an entry containing 0 for the name and 0 for the form." So
the first check is correct.
Make sure dwarf_getabbrev and dwarf_hasattr use the same check.
This is important since all other functions expect dwarf_getabbrev
(__libdw_getabbrev) to have done a data sanity check of the attribute.
So if the ending condition is different it could cause a crash.
Signed-off-by: Mark Wielaard <email@example.com>
libdw/ChangeLog | 7 +++++++
libdw/dwarf_getabbrev.c | 2 +-
libdw/dwarf_hasattr.c | 4 ++--
3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 472d9228..7cb25923 100644
@@ -1,3 +1,10 @@
+2018-08-18 Mark Wielaard <firstname.lastname@example.org>
+ * dwarf_getabbrev.c (__libdw_getabbrev): Continue until both name
+ and form are zero.
+ * dwarf_hasattr.c (dwarf_hasattr): Stop when both name and form
+ are zero.
2018-08-18 Mark Wielaard <email@example.com>
* dwarf_getaranges.c (dwarf_getaranges.c): Make sure there is enough
diff --git a/libdw/dwarf_getabbrev.c b/libdw/dwarf_getabbrev.c
index 988d12c2..6a7e981b 100644
@@ -140,7 +140,7 @@ __libdw_getabbrev (Dwarf *dbg, struct Dwarf_CU *cu, Dwarf_Off offset,
get_sleb128 (formval, abbrevp, end);
- while (attrname != 0 && attrform != 0);
+ while (attrname != 0 || attrform != 0);
/* Return the length to the caller if she asked for it. */
if (lengthp != NULL)
diff --git a/libdw/dwarf_hasattr.c b/libdw/dwarf_hasattr.c
index 90053b13..eca08394 100644
@@ -60,8 +60,8 @@ dwarf_hasattr (Dwarf_Die *die, unsigned int search_name)
unsigned int attr_form;
get_uleb128_unchecked (attr_form, attrp);
- /* We can stop if we found the attribute with value zero. */
- if (attr_name == 0 || attr_form == 0)
+ /* We can stop if we found the end of the attribute list. */
+ if (attr_name == 0 && attr_form == 0)
if (attr_name == search_name)
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