| Message ID | 20210910223613.3225685-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | landlock: Drop "const" argument qualifier to avoid GCC 4.9 warnings | expand |
On 11/09/2021 00:36, Kees Cook wrote: > When building under GCC 4.9, the compiler warns about const mismatches: > > security/landlock/ruleset.c: In function 'insert_rule': > security/landlock/ruleset.c:196:34: error: passing argument 2 of 'create_rule' from incompatible pointer type [-Werror] > new_rule = create_rule(object, &this->layers, this->num_layers, > ^ > security/landlock/ruleset.c:69:30: note: expected 'const struct landlock_layer ** const' but argument is of type 'struct landlock_layer (*)[]' > static struct landlock_rule *create_rule( > ^ > security/landlock/ruleset.c: In function 'landlock_insert_rule': > security/landlock/ruleset.c:240:38: error: passing argument 3 of 'insert_rule' from incompatible pointer type [-Werror] > return insert_rule(ruleset, object, &layers, ARRAY_SIZE(layers)); > ^ > security/landlock/ruleset.c:144:12: note: expected 'const struct landlock_layer ** const' but argument is of type 'struct landlock_layer (*)[1]' > static int insert_rule(struct landlock_ruleset *const ruleset, I guess this is a bug in GCC 4.9 (i.e. missing automatic const upgrade). Couldn't we backport a fix to GCC 4.9 instead? > ^ > > Drop "const" from the function definition. > > Cc: "Mickaël Salaün" <mic@digikod.net> > Cc: James Morris <jmorris@namei.org> > Cc: "Serge E. Hallyn" <serge@hallyn.com> > Cc: linux-security-module@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > security/landlock/ruleset.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c > index ec72b9262bf3..64c37af88ee7 100644 > --- a/security/landlock/ruleset.c > +++ b/security/landlock/ruleset.c > @@ -68,7 +68,7 @@ static void build_check_rule(void) > > static struct landlock_rule *create_rule( > struct landlock_object *const object, > - const struct landlock_layer (*const layers)[], > + struct landlock_layer (*layers)[], The "const layers" is not an issue, it should not be removed. > const u32 num_layers, > const struct landlock_layer *const new_layer) > { > @@ -143,7 +143,7 @@ static void build_check_ruleset(void) > */ > static int insert_rule(struct landlock_ruleset *const ruleset, > struct landlock_object *const object, > - const struct landlock_layer (*const layers)[], > + struct landlock_layer (*layers)[], Same here for the second const. > size_t num_layers) > { > struct rb_node **walker_node; >
On Mon, Sep 13, 2021 at 01:19:19PM +0200, Mickaël Salaün wrote: > > On 11/09/2021 00:36, Kees Cook wrote: > > When building under GCC 4.9, the compiler warns about const mismatches: > > > > security/landlock/ruleset.c: In function 'insert_rule': > > security/landlock/ruleset.c:196:34: error: passing argument 2 of 'create_rule' from incompatible pointer type [-Werror] > > new_rule = create_rule(object, &this->layers, this->num_layers, > > ^ > > security/landlock/ruleset.c:69:30: note: expected 'const struct landlock_layer ** const' but argument is of type 'struct landlock_layer (*)[]' > > static struct landlock_rule *create_rule( > > ^ > > security/landlock/ruleset.c: In function 'landlock_insert_rule': > > security/landlock/ruleset.c:240:38: error: passing argument 3 of 'insert_rule' from incompatible pointer type [-Werror] > > return insert_rule(ruleset, object, &layers, ARRAY_SIZE(layers)); > > ^ > > security/landlock/ruleset.c:144:12: note: expected 'const struct landlock_layer ** const' but argument is of type 'struct landlock_layer (*)[1]' > > static int insert_rule(struct landlock_ruleset *const ruleset, > > I guess this is a bug in GCC 4.9 (i.e. missing automatic const upgrade). > Couldn't we backport a fix to GCC 4.9 instead? I don't disagree, but I'm just trying to deal with the fall-out of -Werror. Perhaps speak up on this thread in support of deprecating GCC 4.9? https://lore.kernel.org/lkml/20210910234047.1019925-1-ndesaulniers@google.com/ -Kees
diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c index ec72b9262bf3..64c37af88ee7 100644 --- a/security/landlock/ruleset.c +++ b/security/landlock/ruleset.c @@ -68,7 +68,7 @@ static void build_check_rule(void) static struct landlock_rule *create_rule( struct landlock_object *const object, - const struct landlock_layer (*const layers)[], + struct landlock_layer (*layers)[], const u32 num_layers, const struct landlock_layer *const new_layer) { @@ -143,7 +143,7 @@ static void build_check_ruleset(void) */ static int insert_rule(struct landlock_ruleset *const ruleset, struct landlock_object *const object, - const struct landlock_layer (*const layers)[], + struct landlock_layer (*layers)[], size_t num_layers) { struct rb_node **walker_node;
When building under GCC 4.9, the compiler warns about const mismatches: security/landlock/ruleset.c: In function 'insert_rule': security/landlock/ruleset.c:196:34: error: passing argument 2 of 'create_rule' from incompatible pointer type [-Werror] new_rule = create_rule(object, &this->layers, this->num_layers, ^ security/landlock/ruleset.c:69:30: note: expected 'const struct landlock_layer ** const' but argument is of type 'struct landlock_layer (*)[]' static struct landlock_rule *create_rule( ^ security/landlock/ruleset.c: In function 'landlock_insert_rule': security/landlock/ruleset.c:240:38: error: passing argument 3 of 'insert_rule' from incompatible pointer type [-Werror] return insert_rule(ruleset, object, &layers, ARRAY_SIZE(layers)); ^ security/landlock/ruleset.c:144:12: note: expected 'const struct landlock_layer ** const' but argument is of type 'struct landlock_layer (*)[1]' static int insert_rule(struct landlock_ruleset *const ruleset, ^ Drop "const" from the function definition. Cc: "Mickaël Salaün" <mic@digikod.net> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: linux-security-module@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> --- security/landlock/ruleset.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)