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| author | Simon McVittie <smcv@collabora.com> | 2022-09-12 13:14:18 +0100 |
|---|---|---|
| committer | Simon McVittie <smcv@collabora.com> | 2022-10-05 10:24:09 +0100 |
| commit | 079bbf16186e87fb0157adf8951f19864bc2ed69 (patch) | |
| tree | 8d1cc0570c606605f5c0f9a97271aea2e1e904c0 /dbus | |
| parent | 67800ac5febc9f15d6c4f113c758797472842ff3 (diff) | |
| download | dbus-079bbf16186e87fb0157adf8951f19864bc2ed69.tar.gz | |
dbus-marshal-validate: Validate length of arrays of fixed-length items
This fast-path previously did not check that the array was made up
of an integer number of items. This could lead to assertion failures
and out-of-bounds accesses during subsequent message processing (which
assumes that the message has already been validated), particularly after
the addition of _dbus_header_remove_unknown_fields(), which makes it
more likely that dbus-daemon will apply non-trivial edits to messages.
Thanks: Evgeny Vereshchagin
Fixes: e61f13cf "Bug 18064 - more efficient validation for fixed-size type arrays"
Resolves: https://gitlab.freedesktop.org/dbus/dbus/-/issues/413
Resolves: CVE-2022-42011
Signed-off-by: Simon McVittie <smcv@collabora.com>
Diffstat (limited to 'dbus')
| -rw-r--r-- | dbus/dbus-marshal-validate.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/dbus/dbus-marshal-validate.c b/dbus/dbus-marshal-validate.c index ae68414d..7d0d6cf7 100644 --- a/dbus/dbus-marshal-validate.c +++ b/dbus/dbus-marshal-validate.c @@ -503,13 +503,24 @@ validate_body_helper (DBusTypeReader *reader, */ if (dbus_type_is_fixed (array_elem_type)) { + /* Note that fixed-size types all have sizes equal to + * their alignments, so this is really the item size. */ + alignment = _dbus_type_get_alignment (array_elem_type); + _dbus_assert (alignment == 1 || alignment == 2 || + alignment == 4 || alignment == 8); + + /* Because the alignment is a power of 2, this is + * equivalent to: (claimed_len % alignment) != 0, + * but avoids slower integer division */ + if ((claimed_len & (alignment - 1)) != 0) + return DBUS_INVALID_ARRAY_LENGTH_INCORRECT; + /* bools need to be handled differently, because they can * have an invalid value */ if (array_elem_type == DBUS_TYPE_BOOLEAN) { dbus_uint32_t v; - alignment = _dbus_type_get_alignment (array_elem_type); while (p < array_end) { |