acl: Annotate struct posix_acl with __counted_by()

Add the __counted_by compiler attribute to the flexible array member
a_entries to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and
CONFIG_FORTIFY_SOURCE.

Use struct_size() to calculate the number of bytes to allocate for new
and cloned acls and remove the local size variables.

Change the posix_acl_alloc() function parameter count from int to
unsigned int to match posix_acl's a_count data type. Add identifier
names to the function definition to silence two checkpatch warnings.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://lore.kernel.org/r/20241018121426.155247-2-thorsten.blum@linux.dev
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Thorsten Blum 2024-10-18 14:14:21 +02:00 committed by Christian Brauner
parent 99bdadbde9
commit 8c6e03ffed
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
2 changed files with 8 additions and 9 deletions

View File

@ -200,11 +200,11 @@ EXPORT_SYMBOL(posix_acl_init);
* Allocate a new ACL with the specified number of entries.
*/
struct posix_acl *
posix_acl_alloc(int count, gfp_t flags)
posix_acl_alloc(unsigned int count, gfp_t flags)
{
const size_t size = sizeof(struct posix_acl) +
count * sizeof(struct posix_acl_entry);
struct posix_acl *acl = kmalloc(size, flags);
struct posix_acl *acl;
acl = kmalloc(struct_size(acl, a_entries, count), flags);
if (acl)
posix_acl_init(acl, count);
return acl;
@ -220,9 +220,8 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
struct posix_acl *clone = NULL;
if (acl) {
int size = sizeof(struct posix_acl) + acl->a_count *
sizeof(struct posix_acl_entry);
clone = kmemdup(acl, size, flags);
clone = kmemdup(acl, struct_size(acl, a_entries, acl->a_count),
flags);
if (clone)
refcount_set(&clone->a_refcount, 1);
}

View File

@ -30,7 +30,7 @@ struct posix_acl {
refcount_t a_refcount;
unsigned int a_count;
struct rcu_head a_rcu;
struct posix_acl_entry a_entries[];
struct posix_acl_entry a_entries[] __counted_by(a_count);
};
#define FOREACH_ACL_ENTRY(pa, acl, pe) \
@ -62,7 +62,7 @@ posix_acl_release(struct posix_acl *acl)
/* posix_acl.c */
extern void posix_acl_init(struct posix_acl *, int);
extern struct posix_acl *posix_acl_alloc(int, gfp_t);
extern struct posix_acl *posix_acl_alloc(unsigned int count, gfp_t flags);
extern struct posix_acl *posix_acl_from_mode(umode_t, gfp_t);
extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
extern int __posix_acl_create(struct posix_acl **, gfp_t, umode_t *);