diff options
author | Simon McVittie <smcv@collabora.com> | 2022-09-13 15:10:22 +0100 |
---|---|---|
committer | Simon McVittie <smcv@collabora.com> | 2022-10-05 10:23:28 +0100 |
commit | 9d07424e9011e3bbe535e83043d335f3093d2916 (patch) | |
tree | fa6ed140293c2998e3985c9aa951dcbb56940b82 /dbus | |
parent | 1ecbbc3760a0604a170fdd4308d893d0fe7128e6 (diff) | |
download | dbus-9d07424e9011e3bbe535e83043d335f3093d2916.tar.gz |
dbus-marshal-validate: Check brackets in signature nest correctly
In debug builds with assertions enabled, a signature with incorrectly
nested `()` and `{}`, for example `a{i(u}` or `(a{ii)}`, could result
in an assertion failure.
In production builds without assertions enabled, a signature with
incorrectly nested `()` and `{}` could potentially result in a crash
or incorrect message parsing, although we do not have a concrete example
of either of these failure modes.
Thanks: Evgeny Vereshchagin
Resolves: https://gitlab.freedesktop.org/dbus/dbus/-/issues/418
Resolves: CVE-2022-42010
Signed-off-by: Simon McVittie <smcv@collabora.com>
Diffstat (limited to 'dbus')
-rw-r--r-- | dbus/dbus-marshal-validate.c | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/dbus/dbus-marshal-validate.c b/dbus/dbus-marshal-validate.c index 4d492f3f..ae68414d 100644 --- a/dbus/dbus-marshal-validate.c +++ b/dbus/dbus-marshal-validate.c @@ -62,6 +62,8 @@ _dbus_validate_signature_with_reason (const DBusString *type_str, int element_count; DBusList *element_count_stack; + char opened_brackets[DBUS_MAXIMUM_TYPE_RECURSION_DEPTH * 2 + 1] = { '\0' }; + char last_bracket; result = DBUS_VALID; element_count_stack = NULL; @@ -93,6 +95,10 @@ _dbus_validate_signature_with_reason (const DBusString *type_str, while (p != end) { + _dbus_assert (struct_depth + dict_entry_depth >= 0); + _dbus_assert (struct_depth + dict_entry_depth < _DBUS_N_ELEMENTS (opened_brackets)); + _dbus_assert (opened_brackets[struct_depth + dict_entry_depth] == '\0'); + switch (*p) { case DBUS_TYPE_BYTE: @@ -136,6 +142,10 @@ _dbus_validate_signature_with_reason (const DBusString *type_str, goto out; } + _dbus_assert (struct_depth + dict_entry_depth >= 1); + _dbus_assert (struct_depth + dict_entry_depth < _DBUS_N_ELEMENTS (opened_brackets)); + _dbus_assert (opened_brackets[struct_depth + dict_entry_depth - 1] == '\0'); + opened_brackets[struct_depth + dict_entry_depth - 1] = DBUS_STRUCT_BEGIN_CHAR; break; case DBUS_STRUCT_END_CHAR: @@ -151,9 +161,20 @@ _dbus_validate_signature_with_reason (const DBusString *type_str, goto out; } + _dbus_assert (struct_depth + dict_entry_depth >= 1); + _dbus_assert (struct_depth + dict_entry_depth < _DBUS_N_ELEMENTS (opened_brackets)); + last_bracket = opened_brackets[struct_depth + dict_entry_depth - 1]; + + if (last_bracket != DBUS_STRUCT_BEGIN_CHAR) + { + result = DBUS_INVALID_STRUCT_ENDED_BUT_NOT_STARTED; + goto out; + } + _dbus_list_pop_last (&element_count_stack); struct_depth -= 1; + opened_brackets[struct_depth + dict_entry_depth] = '\0'; break; case DBUS_DICT_ENTRY_BEGIN_CHAR: @@ -178,6 +199,10 @@ _dbus_validate_signature_with_reason (const DBusString *type_str, goto out; } + _dbus_assert (struct_depth + dict_entry_depth >= 1); + _dbus_assert (struct_depth + dict_entry_depth < _DBUS_N_ELEMENTS (opened_brackets)); + _dbus_assert (opened_brackets[struct_depth + dict_entry_depth - 1] == '\0'); + opened_brackets[struct_depth + dict_entry_depth - 1] = DBUS_DICT_ENTRY_BEGIN_CHAR; break; case DBUS_DICT_ENTRY_END_CHAR: @@ -186,8 +211,19 @@ _dbus_validate_signature_with_reason (const DBusString *type_str, result = DBUS_INVALID_DICT_ENTRY_ENDED_BUT_NOT_STARTED; goto out; } - + + _dbus_assert (struct_depth + dict_entry_depth >= 1); + _dbus_assert (struct_depth + dict_entry_depth < _DBUS_N_ELEMENTS (opened_brackets)); + last_bracket = opened_brackets[struct_depth + dict_entry_depth - 1]; + + if (last_bracket != DBUS_DICT_ENTRY_BEGIN_CHAR) + { + result = DBUS_INVALID_DICT_ENTRY_ENDED_BUT_NOT_STARTED; + goto out; + } + dict_entry_depth -= 1; + opened_brackets[struct_depth + dict_entry_depth] = '\0'; element_count = _DBUS_POINTER_TO_INT (_dbus_list_pop_last (&element_count_stack)); |