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.
Signed-off-by: Thorsten Blum <thorsten.b...@linux.dev>
---
fs/posix_acl.c | 13 ++++++-------
include/linux/posix_acl.h | 4 ++--
2 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 6c66a37522d0..4050942ab52f 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -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);
}
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 0e65b3d634d9..83b2c5fba1d9 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -30,7 +30,7 @@ struct posix_acl {
refcount_t a_refcount;
struct rcu_head a_rcu;
unsigned int a_count;
- 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 *);
--
2.46.1
