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 >
