[PATCH] random: kmalloc failure ignored in init_std_data()

[PATCH] random: kmalloc failure ignored in init_std_data()

[Roel Kluin]

Clean up and error out if kmalloc() fails.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
Found with sed: http://kernelnewbies.org/roelkluin

Build tested. Please review

diff --git a/drivers/char/random.c b/drivers/char/random.c
index d8a9255..8a68be8 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -939,7 +939,7 @@ EXPORT_SYMBOL(get_random_bytes);
  * data into the pool to prepare it for use. The pool is not cleared
  * as that can only decrease the entropy in the pool.
  */
-static void init_std_data(struct entropy_store *r)
+static int init_std_data(struct entropy_store *r)
 {
 	ktime_t now;
 	unsigned long flags;
@@ -952,16 +952,35 @@ static void init_std_data(struct entropy_store *r)
 	mix_pool_bytes(r, &now, sizeof(now));
 	mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
 	/* Enable continuous test in fips mode */
-	if (fips_enabled)
+	if (fips_enabled) {
 		r->last_data = kmalloc(EXTRACT_SIZE, GFP_KERNEL);
+		if (r->last_data == NULL)
+			return -ENOMEM;
+	}
+	return 0;
 }
 
 static int rand_initialize(void)
 {
-	init_std_data(&input_pool);
-	init_std_data(&blocking_pool);
-	init_std_data(&nonblocking_pool);
+	int ret;
+	ret = init_std_data(&input_pool);
+	if (ret != 0)
+		return ret;
+
+	ret = init_std_data(&blocking_pool);
+	if (ret != 0)
+		goto free_ip_ld;
+
+	ret = init_std_data(&nonblocking_pool);
+	if (ret != 0)
+		goto free_bp_ld;
+
 	return 0;
+free_bp_ld:
+	kfree(blocking_pool.last_data);
+free_ip_ld:
+	kfree(input_pool.last_data);
+	return ret;
 }
 module_init(rand_initialize);
 
@@ -1160,8 +1179,8 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 		/* Clear the entropy pool counters. */
 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
-		rand_initialize();
-		return 0;
+		retval = rand_initialize();
+		return retval;
 	default:
 		return -EINVAL;
 	}

Re: [PATCH] random: kmalloc failure ignored in init_std_data()

[Matt Mackall]

On Sat, 2009-09-19 at 01:03 +0200, Roel Kluin wrote:
> Clean up and error out if kmalloc() fails.

No thanks. Let's instead make it so it can't fail by building the array
into the statically allocated pool structures.

> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> Found with sed: http://kernelnewbies.org/roelkluin
> 
> Build tested. Please review
> 
> diff --git a/drivers/char/random.c b/drivers/char/random.c
> index d8a9255..8a68be8 100644
> --- a/drivers/char/random.c
> +++ b/drivers/char/random.c
> @@ -939,7 +939,7 @@ EXPORT_SYMBOL(get_random_bytes);
>   * data into the pool to prepare it for use. The pool is not cleared
>   * as that can only decrease the entropy in the pool.
>   */
> -static void init_std_data(struct entropy_store *r)
> +static int init_std_data(struct entropy_store *r)
>  {
>  	ktime_t now;
>  	unsigned long flags;
> @@ -952,16 +952,35 @@ static void init_std_data(struct entropy_store *r)
>  	mix_pool_bytes(r, &now, sizeof(now));
>  	mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
>  	/* Enable continuous test in fips mode */
> -	if (fips_enabled)
> +	if (fips_enabled) {
>  		r->last_data = kmalloc(EXTRACT_SIZE, GFP_KERNEL);
> +		if (r->last_data == NULL)
> +			return -ENOMEM;
> +	}
> +	return 0;
>  }
>  
>  static int rand_initialize(void)
>  {
> -	init_std_data(&input_pool);
> -	init_std_data(&blocking_pool);
> -	init_std_data(&nonblocking_pool);
> +	int ret;
> +	ret = init_std_data(&input_pool);
> +	if (ret != 0)
> +		return ret;
> +
> +	ret = init_std_data(&blocking_pool);
> +	if (ret != 0)
> +		goto free_ip_ld;
> +
> +	ret = init_std_data(&nonblocking_pool);
> +	if (ret != 0)
> +		goto free_bp_ld;
> +
>  	return 0;
> +free_bp_ld:
> +	kfree(blocking_pool.last_data);
> +free_ip_ld:
> +	kfree(input_pool.last_data);
> +	return ret;
>  }
>  module_init(rand_initialize);
>  
> @@ -1160,8 +1179,8 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
>  		/* Clear the entropy pool counters. */
>  		if (!capable(CAP_SYS_ADMIN))
>  			return -EPERM;
> -		rand_initialize();
> -		return 0;
> +		retval = rand_initialize();
> +		return retval;
>  	default:
>  		return -EINVAL;
>  	}

-- 
http://selenic.com : development and support for Mercurial and Linux

Re: [PATCH] random: kmalloc failure ignored in init_std_data()

[Roel Kluin]

kmalloc may fail so build the array into the statically allocated
pool structures instead.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
Is this what you had in mind? (it builds)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index d8a9255..9012540 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -400,6 +400,8 @@ module_param(debug, bool, 0644);
  *
  **********************************************************************/
 
+#define EXTRACT_SIZE 10
+
 struct entropy_store;
 struct entropy_store {
 	/* read-only data: */
@@ -414,7 +416,9 @@ struct entropy_store {
 	unsigned add_ptr;
 	int entropy_count;
 	int input_rotate;
-	__u8 *last_data;
+#ifdef CONFIG_CRYPTO_FIPS
+	__u8 last_data[EXTRACT_SIZE];
+#endif
 };
 
 static __u32 input_pool_data[INPUT_POOL_WORDS];
@@ -714,8 +718,6 @@ void add_disk_randomness(struct gendisk *disk)
 }
 #endif
 
-#define EXTRACT_SIZE 10
-
 /*********************************************************************
  *
  * Entropy extraction routines
@@ -951,9 +953,6 @@ static void init_std_data(struct entropy_store *r)
 	now = ktime_get_real();
 	mix_pool_bytes(r, &now, sizeof(now));
 	mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
-	/* Enable continuous test in fips mode */
-	if (fips_enabled)
-		r->last_data = kmalloc(EXTRACT_SIZE, GFP_KERNEL);
 }
 
 static int rand_initialize(void)

Re: [PATCH] random: kmalloc failure ignored in init_std_data()

[Matt Mackall]

On Sat, 2009-09-19 at 02:54 +0200, Roel Kluin wrote:
> kmalloc may fail so build the array into the statically allocated
> pool structures instead.
> 
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> Is this what you had in mind? (it builds)

Yes, looks good.

Acked-by: Matt Mackall <mpm@selenic.com>

> diff --git a/drivers/char/random.c b/drivers/char/random.c
> index d8a9255..9012540 100644
> --- a/drivers/char/random.c
> +++ b/drivers/char/random.c
> @@ -400,6 +400,8 @@ module_param(debug, bool, 0644);
>   *
>   **********************************************************************/
>  
> +#define EXTRACT_SIZE 10
> +
>  struct entropy_store;
>  struct entropy_store {
>  	/* read-only data: */
> @@ -414,7 +416,9 @@ struct entropy_store {
>  	unsigned add_ptr;
>  	int entropy_count;
>  	int input_rotate;
> -	__u8 *last_data;
> +#ifdef CONFIG_CRYPTO_FIPS
> +	__u8 last_data[EXTRACT_SIZE];
> +#endif
>  };
>  
>  static __u32 input_pool_data[INPUT_POOL_WORDS];
> @@ -714,8 +718,6 @@ void add_disk_randomness(struct gendisk *disk)
>  }
>  #endif
>  
> -#define EXTRACT_SIZE 10
> -
>  /*********************************************************************
>   *
>   * Entropy extraction routines
> @@ -951,9 +953,6 @@ static void init_std_data(struct entropy_store *r)
>  	now = ktime_get_real();
>  	mix_pool_bytes(r, &now, sizeof(now));
>  	mix_pool_bytes(r, utsname(), sizeof(*(utsname())));
> -	/* Enable continuous test in fips mode */
> -	if (fips_enabled)
> -		r->last_data = kmalloc(EXTRACT_SIZE, GFP_KERNEL);
>  }
>  
>  static int rand_initialize(void)

-- 
http://selenic.com : development and support for Mercurial and Linux

Re: [PATCH] random: kmalloc failure ignored in init_std_data()

[Andrew Morton]

On Sat, 19 Sep 2009 02:54:07 +0200 Roel Kluin <roel.kluin@gmail.com> wrote:

> kmalloc may fail so build the array into the statically allocated
> pool structures instead.

x86_64 allnoconfig:

drivers/char/random.c: In function 'extract_entropy':
drivers/char/random.c:867: error: 'struct entropy_store' has no member named 'last_data'
drivers/char/random.c:869: error: 'struct entropy_store' has no member named 'last_data'
drivers/char/random.c:871: error: 'struct entropy_store' has no member named 'last_data'
drivers/char/random.c:871: error: 'struct entropy_store' has no member named 'last_data'