On Mon, Jan 06, 2025 at 06:04:56PM +0100, Mickaël Salaün wrote:
> On Sat, Jan 04, 2025 at 07:26:27AM +0800, kernel test robot wrote:
> > security/landlock/ruleset.c: In function 'create_rule':
> > >> security/landlock/ruleset.c:96:9: warning: 'memcpy' accessing 4294967295
> > >> bytes at offsets 20 and 0 overlaps 6442450943 bytes at offset
> > >> -2147483648 [-Wrestrict]
> > 96 | memcpy(new_rule->layers, layers,
> > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 97 | flex_array_size(new_rule, layers,
> > num_layers));
> > |
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> I guess the GCC warning is a false positive?
> See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116494
Does the warning go away if flex_array_size() is open-coded or if the
create_rule prototype uses "*" instead of "[]" syntax for the "layers"
argument?
The warning is about the "read" part ("accessing"). Using tip-of-tree
gcc with -fdiagnostics-details might show more details on the calling
path.
-Kees
--
Kees Cook
