Re: [Keyrings] [PATCH] KEYS: Add an RCU payload dereference macro

[Mimi Zohar]

On Thu, 2011-03-03 at 17:32 +0000, David Howells wrote:
> Add an RCU payload dereference macro as this seems to be a common piece of code
> amongst key types that use RCU referenced payloads.
> 
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>

Yes, a lot cleaner. thanks!

Signed-of-by: Mimi Zohar <zohar@xxxxxxxxxx>

> ---
> 
>  include/linux/key.h          |    4 ++++
>  security/keys/encrypted.c    |    3 +--
>  security/keys/trusted.c      |    3 +--
>  security/keys/user_defined.c |    3 +--
>  4 files changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/key.h b/include/linux/key.h
> index 3db0adc..a6b1edc 100644
> --- a/include/linux/key.h
> +++ b/include/linux/key.h
> @@ -275,6 +275,10 @@ static inline key_serial_t key_serial(struct key *key)
>  	return key ? key->serial : 0;
>  }
> 
> +#define rcu_dereference_key(KEY)					\
> +	(rcu_dereference_protected((KEY)->payload.rcudata,		\
> +				   rwsem_is_locked(&((struct key *)(KEY))->sem)))
> +
>  #ifdef CONFIG_SYSCTL
>  extern ctl_table key_sysctls[];
>  #endif
> diff --git a/security/keys/encrypted.c b/security/keys/encrypted.c
> index 9e7e4ce..69907a5 100644
> --- a/security/keys/encrypted.c
> +++ b/security/keys/encrypted.c
> @@ -765,8 +765,7 @@ static long encrypted_read(const struct key *key, char __user *buffer,
>  	size_t asciiblob_len;
>  	int ret;
> 
> -	epayload = rcu_dereference_protected(key->payload.data,
> -				  rwsem_is_locked(&((struct key *)key)->sem));
> +	epayload = rcu_dereference_key(key);
> 
>  	/* returns the hex encoded iv, encrypted-data, and hmac as ascii */
>  	asciiblob_len = epayload->datablob_len + ivsize + 1
> diff --git a/security/keys/trusted.c b/security/keys/trusted.c
> index 83fc92e..c99b936 100644
> --- a/security/keys/trusted.c
> +++ b/security/keys/trusted.c
> @@ -1076,8 +1076,7 @@ static long trusted_read(const struct key *key, char __user *buffer,
>  	char *bufp;
>  	int i;
> 
> -	p = rcu_dereference_protected(key->payload.data,
> -			rwsem_is_locked(&((struct key *)key)->sem));
> +	p = rcu_dereference_key(key);
>  	if (!p)
>  		return -EINVAL;
>  	if (!buffer || buflen <= 0)
> diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
> index 02807fb..c6ca866 100644
> --- a/security/keys/user_defined.c
> +++ b/security/keys/user_defined.c
> @@ -184,8 +184,7 @@ long user_read(const struct key *key, char __user *buffer, size_t buflen)
>  	struct user_key_payload *upayload;
>  	long ret;
> 
> -	upayload = rcu_dereference_protected(
> -		key->payload.data, rwsem_is_locked(&((struct key *)key)->sem));
> +	upayload = rcu_dereference_key(key);
>  	ret = upayload->datalen;
> 
>  	/* we can return the data as is */
> 
> _______________________________________________
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