On Fri, May 26, 2017 at 1:17 PM, Kees Cook <[email protected]> wrote: > This is another false positive in bad cast detection: > > net/unix/af_unix.c: In function ‘unix_skb_scm_eq’: > net/unix/af_unix.c:1621:31: note: found mismatched rhs struct pointer types: > ‘struct unix_skb_parms’ and ‘char’ > > const struct unix_skb_parms *u = &UNIXCB(skb); > ^ > > UNIXCB is: > > #define UNIXCB(skb) (*(struct unix_skb_parms *)&((skb)->cb)) > > And ->cb is: > > char cb[48] __aligned(8); > > This is a rather crazy cast, but appears to be safe in the face of > randomization, so whitelist it in the plugin. > > Cc: Hannes Frederic Sowa <[email protected]> > Cc: Signed-off-by: David S. Miller <[email protected]>
Argh, paste-o. I was adding git history folks here to Cc, pardon the glitch. This should be Cc: and absolutely not a S-o-B from Dave. -Kees > Signed-off-by: Kees Cook <[email protected]> > --- > scripts/gcc-plugins/randomize_layout_plugin.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/scripts/gcc-plugins/randomize_layout_plugin.c > b/scripts/gcc-plugins/randomize_layout_plugin.c > index e126ac7874af..bf110915a5aa 100644 > --- a/scripts/gcc-plugins/randomize_layout_plugin.c > +++ b/scripts/gcc-plugins/randomize_layout_plugin.c > @@ -43,6 +43,8 @@ struct whitelist_entry { > }; > > static const struct whitelist_entry whitelist[] = { > + /* unix_skb_parms via UNIXCB() buffer */ > + { "net/unix/af_unix.c", "unix_skb_parms", "char" }, > /* walk struct security_hook_heads as an array of struct list_head */ > { "security/security.c", "list_head", "security_hook_heads" }, > { } > -- > 2.7.4 > -- Kees Cook Pixel Security
