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| author | Christian Linhart <chris@demorecorder.com> | 2015-09-13 15:45:15 +0200 |
|---|---|---|
| committer | Christian Linhart <chris@demorecorder.com> | 2015-10-26 17:35:16 +0100 |
| commit | f4348694c939f83e7135df4779d1bd138836c4db (patch) | |
| tree | 3142b74b2a8a3c195cadbbe3536c333f2d5d83e8 | |
| parent | 1601efa74cf128ac53cb507cc0392d7554f25c1a (diff) | |
xselinux: add explicit padding for struc "ListItem"
This is needed so that subsequent list-items in a list are aligned
to 4 bytes which is necessary because ListItem contains 32-bit values
of types ATOM and CARD32. (Actually, only the final align-pad
is needed for that.)
The xserver makes sure that the length of both char-lists is a multiple of 4:
http://cgit.freedesktop.org/xorg/xserver/tree/Xext/xselinux_ext.c?id=xorg-server-1.17.99.901#n360
So, instead of a explicit padding we could add something like an assertion
or precondition that the fields "object_context_len" and "data_context_len"
have to be a multiple of 4.
Unfortunately I couldn't find a protocol specification of the xselinux
extension, to see whether the multiple of 4 is mandated by the protocol spec
or whether there should be align-pads. (and whether there should
be an align pad between "object_context" and "data_context"
Does anybody know where the spec for the xselinux protocol is?
There ought to be a spec somewhere for this because this is
security relevant.
Signed-off-by: Christian Linhart <chris@demorecorder.com>
Reviewed-by: Peter Harris <pharris@opentext.com>
| -rw-r--r-- | src/xselinux.xml | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/xselinux.xml b/src/xselinux.xml index 7751470..a97a146 100644 --- a/src/xselinux.xml +++ b/src/xselinux.xml @@ -111,9 +111,11 @@ authorization from the authors. <list type="char" name="object_context"> <fieldref>object_context_len</fieldref> </list> + <pad align="4" /> <list type="char" name="data_context"> <fieldref>data_context_len</fieldref> </list> + <pad align="4" /> </struct> <request name="SetPropertyCreateContext" opcode="8"> |