On 2022/5/18 12:55, Gustavo A. R. Silva wrote:
On Wed, May 18, 2022 at 08:56:39AM +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
The warnings above are not silenced with this patch as struct_size()
internally use sizeof on the struct-with-flex-array.
However, the use of struct_size() instead of the open-coded expressions
in the calls to kmalloc() is correct.
Reference: https://github.com/KSPP/linux/issues/174
I updated this issue on the issue tracker. Please, from now on, just
use that issue as a list of potential open-coded instances to be
audited. :)
Signed-off-by: GUO Zihua <guozihua@xxxxxxxxxx>
Reviewed-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
Thanks
--
Gustavo
---
v2:
Use size_add() helper following Kees Cook's suggestion.
---
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..e020222b1fe5 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, size_add(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);
--
2.36.0
.
Thanks for the review Gustavo.
I'll send a v3 patch and update the commit message. Maybe refer to the
mail from Linus instead.
--
Best
GUO Zihua
