diff mbox series

crypto: Use struct_size() helper in kmalloc()

Message ID 20220517080532.31015-1-guozihua@huawei.com (mailing list archive)
State New
Headers show
Series crypto: Use struct_size() helper in kmalloc() | expand

Commit Message

GUO Zihua May 17, 2022, 8:05 a.m. UTC
Make use of struct_size() heler for structures containing flexible array
member instead of sizeof() which prevents potential issues as well as
addressing the following sparse warning:

crypto/asymmetric_keys/asymmetric_type.c:155:23: warning: using sizeof
on a flexible structure
crypto/asymmetric_keys/asymmetric_type.c:247:28: warning: using sizeof
on a flexible structure

Reference: https://github.com/KSPP/linux/issues/174

Signed-off-by: GUO Zihua <guozihua@huawei.com>
---
 crypto/asymmetric_keys/asymmetric_type.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Kees Cook May 17, 2022, 9:26 p.m. UTC | #1
On Tue, May 17, 2022 at 04:05:32PM +0800, GUO Zihua wrote:
> Make use of struct_size() heler for structures containing flexible array
> member instead of sizeof() which prevents potential issues as well as
> addressing the following sparse warning:
> 
> crypto/asymmetric_keys/asymmetric_type.c:155:23: warning: using sizeof
> on a flexible structure
> crypto/asymmetric_keys/asymmetric_type.c:247:28: warning: using sizeof
> on a flexible structure
> 
> Reference: https://github.com/KSPP/linux/issues/174
> 
> Signed-off-by: GUO Zihua <guozihua@huawei.com>
> ---
>  crypto/asymmetric_keys/asymmetric_type.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
> index 41a2f0eb4ce4..96a99a91bf17 100644
> --- a/crypto/asymmetric_keys/asymmetric_type.c
> +++ b/crypto/asymmetric_keys/asymmetric_type.c
> @@ -152,7 +152,7 @@ struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
>  {
>  	struct asymmetric_key_id *kid;
>  
> -	kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
> +	kid = kmalloc(struct_size(kid, data, len_1 + len_2),

Please use the size_add() helper for this open-coded add here.

>  		      GFP_KERNEL);
>  	if (!kid)
>  		return ERR_PTR(-ENOMEM);
> @@ -244,7 +244,7 @@ struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
>  	if (asciihexlen & 1)
>  		return ERR_PTR(-EINVAL);
>  
> -	match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
> +	match_id = kmalloc(struct_size(match_id, data, asciihexlen / 2),

There is no size_div(), but that's ok here because the denominator is an
constant expression.

>  			   GFP_KERNEL);
>  	if (!match_id)
>  		return ERR_PTR(-ENOMEM);
> -- 
> 2.36.0
>
GUO Zihua May 18, 2022, 1:01 a.m. UTC | #2
On 2022/5/18 5:26, Kees Cook wrote:
> On Tue, May 17, 2022 at 04:05:32PM +0800, GUO Zihua wrote:
>> Make use of struct_size() heler for structures containing flexible array
>> member instead of sizeof() which prevents potential issues as well as
>> addressing the following sparse warning:
>>
>> crypto/asymmetric_keys/asymmetric_type.c:155:23: warning: using sizeof
>> on a flexible structure
>> crypto/asymmetric_keys/asymmetric_type.c:247:28: warning: using sizeof
>> on a flexible structure
>>
>> Reference: https://github.com/KSPP/linux/issues/174
>>
>> Signed-off-by: GUO Zihua <guozihua@huawei.com>
>> ---
>>   crypto/asymmetric_keys/asymmetric_type.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
>> index 41a2f0eb4ce4..96a99a91bf17 100644
>> --- a/crypto/asymmetric_keys/asymmetric_type.c
>> +++ b/crypto/asymmetric_keys/asymmetric_type.c
>> @@ -152,7 +152,7 @@ struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
>>   {
>>   	struct asymmetric_key_id *kid;
>>   
>> -	kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
>> +	kid = kmalloc(struct_size(kid, data, len_1 + len_2),
> 
> Please use the size_add() helper for this open-coded add here.
> 
>>   		      GFP_KERNEL);
>>   	if (!kid)
>>   		return ERR_PTR(-ENOMEM);
>> @@ -244,7 +244,7 @@ struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
>>   	if (asciihexlen & 1)
>>   		return ERR_PTR(-EINVAL);
>>   
>> -	match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
>> +	match_id = kmalloc(struct_size(match_id, data, asciihexlen / 2),
> 
> There is no size_div(), but that's ok here because the denominator is an
> constant expression.
> 
>>   			   GFP_KERNEL);
>>   	if (!match_id)
>>   		return ERR_PTR(-ENOMEM);
>> -- 
>> 2.36.0
>>
> 

Thanks Kees,

A v2 patch has been submitted.
diff mbox series

Patch

diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c
index 41a2f0eb4ce4..96a99a91bf17 100644
--- a/crypto/asymmetric_keys/asymmetric_type.c
+++ b/crypto/asymmetric_keys/asymmetric_type.c
@@ -152,7 +152,7 @@  struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
 {
 	struct asymmetric_key_id *kid;
 
-	kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
+	kid = kmalloc(struct_size(kid, data, len_1 + len_2),
 		      GFP_KERNEL);
 	if (!kid)
 		return ERR_PTR(-ENOMEM);
@@ -244,7 +244,7 @@  struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
 	if (asciihexlen & 1)
 		return ERR_PTR(-EINVAL);
 
-	match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
+	match_id = kmalloc(struct_size(match_id, data, asciihexlen / 2),
 			   GFP_KERNEL);
 	if (!match_id)
 		return ERR_PTR(-ENOMEM);