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/block/blk-softirq.c b/block/blk-softirq.c
index 53b1737..489eab8 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c
@@ -18,7 +18,7 @@
* Softirq action handler - move entries to local list and loop over them
* while passing them to the queue registered handler.
*/
-static void blk_done_softirq(struct softirq_action *h)
+static __latent_entropy void blk_done_softirq(struct softirq_action *h)
{
struct list_head *cpu_list, local_list;
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 3efb3bf..7274ae8 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -479,8 +479,8 @@
static void crng_reseed(struct crng_state *crng, struct entropy_store *r);
static void push_to_pool(struct work_struct *work);
-static __u32 input_pool_data[INPUT_POOL_WORDS];
-static __u32 blocking_pool_data[OUTPUT_POOL_WORDS];
+static __u32 input_pool_data[INPUT_POOL_WORDS] __latent_entropy;
+static __u32 blocking_pool_data[OUTPUT_POOL_WORDS] __latent_entropy;
static struct entropy_store input_pool = {
.poolinfo = &poolinfo_table[0],
diff --git a/fs/namespace.c b/fs/namespace.c
index 7bb2cda..4a9568b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2759,6 +2759,7 @@
return new_ns;
}
+__latent_entropy
struct mnt_namespace *copy_mnt_ns(unsigned long flags, struct mnt_namespace *ns,
struct user_namespace *user_ns, struct fs_struct *new_fs)
{
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 573c5a1..432f5c9 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -188,6 +188,13 @@
#endif /* GCC_VERSION >= 40300 */
#if GCC_VERSION >= 40500
+
+#ifndef __CHECKER__
+#ifdef LATENT_ENTROPY_PLUGIN
+#define __latent_entropy __attribute__((latent_entropy))
+#endif
+#endif
+
/*
* Mark a position in code as unreachable. This can be used to
* suppress control flow warnings after asm blocks that transfer
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 6685698..ceaddaf 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -406,6 +406,10 @@
# define __attribute_const__ /* unimplemented */
#endif
+#ifndef __latent_entropy
+# define __latent_entropy
+#endif
+
/*
* Tell gcc if a function is cold. The compiler will assume any path
* directly leading to the call is unlikely.
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),
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 1dbf52f..e0341af 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -437,7 +437,7 @@
extern unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask);
/* drivers/char/random.c */
-extern void add_disk_randomness(struct gendisk *disk);
+extern void add_disk_randomness(struct gendisk *disk) __latent_entropy;
extern void rand_initialize_disk(struct gendisk *disk);
static inline sector_t get_start_sect(struct block_device *bdev)
diff --git a/include/linux/init.h b/include/linux/init.h
index 6935d02..1e5c131 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -39,7 +39,7 @@
/* These are for everybody (although not all archs will actually
discard it in modules) */
-#define __init __section(.init.text) __cold notrace
+#define __init __section(.init.text) __cold notrace __latent_entropy
#define __initdata __section(.init.data)
#define __initconst __constsection(.init.rodata)
#define __exitdata __section(.exit.data)
@@ -86,7 +86,8 @@
#define __exit __section(.exit.text) __exitused __cold notrace
/* Used for MEMORY_HOTPLUG */
-#define __meminit __section(.meminit.text) __cold notrace
+#define __meminit __section(.meminit.text) __cold notrace \
+ __latent_entropy
#define __meminitdata __section(.meminit.data)
#define __meminitconst __constsection(.meminit.rodata)
#define __memexit __section(.memexit.text) __exitused __cold notrace
diff --git a/include/linux/random.h b/include/linux/random.h
index a59c74c..d80a438 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -30,8 +30,8 @@
#endif
extern void add_input_randomness(unsigned int type, unsigned int code,
- unsigned int value);
-extern void add_interrupt_randomness(int irq, int irq_flags);
+ unsigned int value) __latent_entropy;
+extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
extern void get_random_bytes(void *buf, int nbytes);
extern int add_random_ready_callback(struct random_ready_callback *rdy);
diff --git a/kernel/fork.c b/kernel/fork.c
index 001b184..0539388 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -404,7 +404,8 @@
}
#ifdef CONFIG_MMU
-static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
+static __latent_entropy int dup_mmap(struct mm_struct *mm,
+ struct mm_struct *oldmm)
{
struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
struct rb_node **rb_link, *rb_parent;
@@ -1296,7 +1297,8 @@
* parts of the process environment (as per the clone
* flags). The actual kick-off is left to the caller.
*/
-static struct task_struct *copy_process(unsigned long clone_flags,
+static __latent_entropy struct task_struct *copy_process(
+ unsigned long clone_flags,
unsigned long stack_start,
unsigned long stack_size,
int __user *child_tidptr,
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index 944b1b4..1898559 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -170,7 +170,7 @@
false));
}
-static void rcu_process_callbacks(struct softirq_action *unused)
+static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused)
{
__rcu_process_callbacks(&rcu_sched_ctrlblk);
__rcu_process_callbacks(&rcu_bh_ctrlblk);
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 5d80925..e5164de 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3013,7 +3013,7 @@
/*
* Do RCU core processing for the current CPU.
*/
-static void rcu_process_callbacks(struct softirq_action *unused)
+static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused)
{
struct rcu_state *rsp;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 039de34..004996d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8283,7 +8283,7 @@
* run_rebalance_domains is triggered when needed from the scheduler tick.
* Also triggered for nohz idle balancing (with nohz_balancing_kick set).
*/
-static void run_rebalance_domains(struct softirq_action *h)
+static __latent_entropy void run_rebalance_domains(struct softirq_action *h)
{
struct rq *this_rq = this_rq();
enum cpu_idle_type idle = this_rq->idle_balance ?
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 17caf4b..34033fd 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -482,7 +482,7 @@
}
EXPORT_SYMBOL(__tasklet_hi_schedule_first);
-static void tasklet_action(struct softirq_action *a)
+static __latent_entropy void tasklet_action(struct softirq_action *a)
{
struct tasklet_struct *list;
@@ -518,7 +518,7 @@
}
}
-static void tasklet_hi_action(struct softirq_action *a)
+static __latent_entropy void tasklet_hi_action(struct softirq_action *a)
{
struct tasklet_struct *list;
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 32bf6f7..2d47980 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1633,7 +1633,7 @@
/*
* This function runs timers and the timer-tq in bottom half context.
*/
-static void run_timer_softirq(struct softirq_action *h)
+static __latent_entropy void run_timer_softirq(struct softirq_action *h)
{
struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
diff --git a/lib/irq_poll.c b/lib/irq_poll.c
index 836f7db..63be749 100644
--- a/lib/irq_poll.c
+++ b/lib/irq_poll.c
@@ -74,7 +74,7 @@
}
EXPORT_SYMBOL(irq_poll_complete);
-static void irq_poll_softirq(struct softirq_action *h)
+static void __latent_entropy irq_poll_softirq(struct softirq_action *h)
{
struct list_head *list = this_cpu_ptr(&blk_cpu_iopoll);
int rearm = 0, budget = irq_poll_budget;
diff --git a/lib/random32.c b/lib/random32.c
index 69ed593..a309235 100644
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -47,7 +47,7 @@
}
#endif
-static DEFINE_PER_CPU(struct rnd_state, net_rand_state);
+static DEFINE_PER_CPU(struct rnd_state, net_rand_state) __latent_entropy;
/**
* prandom_u32_state - seeded pseudo-random number generator.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 248851d..901121a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -92,7 +92,7 @@
#endif
#ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
-volatile u64 latent_entropy;
+volatile u64 latent_entropy __latent_entropy;
EXPORT_SYMBOL(latent_entropy);
#endif
diff --git a/net/core/dev.c b/net/core/dev.c
index ea63120..ee076c2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3855,7 +3855,7 @@
}
EXPORT_SYMBOL(netif_rx_ni);
-static void net_tx_action(struct softirq_action *h)
+static __latent_entropy void net_tx_action(struct softirq_action *h)
{
struct softnet_data *sd = this_cpu_ptr(&softnet_data);
@@ -5187,7 +5187,7 @@
return work;
}
-static void net_rx_action(struct softirq_action *h)
+static __latent_entropy void net_rx_action(struct softirq_action *h)
{
struct softnet_data *sd = this_cpu_ptr(&softnet_data);
unsigned long time_limit = jiffies + 2;