On Thu, Aug 17, 2023 at 4:22 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > Prepare for the coming implementation by GCC and Clang of the __counted_by > attribute. Flexible array members annotated with __counted_by can have > their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS > (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family > functions). > > As found with Coccinelle[1], add __counted_by for struct sidtab_str_cache. > > [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci > > Cc: Paul Moore <paul@xxxxxxxxxxxxxx> > Cc: Stephen Smalley <stephen.smalley.work@xxxxxxxxx> > Cc: Eric Paris <eparis@xxxxxxxxxxxxxx> > Cc: Ondrej Mosnacek <omosnace@xxxxxxxxxx> > Cc: selinux@xxxxxxxxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > security/selinux/ss/sidtab.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) This also looks good to me, but similarly to the audit patch, since we are at -rc6 I'm going to wait to merge this until after the merge window. I'll send a follow up email once it's merged. Thanks. > diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c > index d8ead463b8df..732fd8e22a12 100644 > --- a/security/selinux/ss/sidtab.c > +++ b/security/selinux/ss/sidtab.c > @@ -25,7 +25,7 @@ struct sidtab_str_cache { > struct list_head lru_member; > struct sidtab_entry *parent; > u32 len; > - char str[]; > + char str[] __counted_by(len); > }; > > #define index_to_sid(index) ((index) + SECINITSID_NUM + 1) > -- > 2.34.1 -- paul-moore.com
