latent_entropy: Mark functions with __latent_entropy
The __latent_entropy gcc attribute can be used only on functions and
variables. If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents. The variable must
be an integer, an integer array type or a structure with integer fields.
These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index 5295535..9852c7e 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -105,7 +105,7 @@
void put_files_struct(struct files_struct *fs);
void reset_files_struct(struct files_struct *);
int unshare_files(struct files_struct **);
-struct files_struct *dup_fd(struct files_struct *, int *);
+struct files_struct *dup_fd(struct files_struct *, int *) __latent_entropy;
void do_close_on_exec(struct files_struct *);
int iterate_fd(struct files_struct *, unsigned,
int (*)(const void *, struct file *, unsigned),