@@ -2879,33 +2879,31 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
if (*ea_inode_array == NULL) {
/*
* Start with 15 inodes, so it fits into a power-of-two size.
- * If *ea_inode_array is NULL, this is essentially offsetof()
*/
- (*ea_inode_array) =
- kmalloc(offsetof(struct ext4_xattr_inode_array,
- inodes[EIA_MASK]),
- GFP_NOFS);
+ (*ea_inode_array) = kmalloc(
+ struct_size(*ea_inode_array, inodes, EIA_MASK),
+ GFP_NOFS);
if (*ea_inode_array == NULL)
return -ENOMEM;
(*ea_inode_array)->count = 0;
} else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) {
/* expand the array once all 15 + n * 16 slots are full */
struct ext4_xattr_inode_array *new_array = NULL;
- int count = (*ea_inode_array)->count;
- /* if new_array is NULL, this is essentially offsetof() */
new_array = kmalloc(
- offsetof(struct ext4_xattr_inode_array,
- inodes[count + EIA_INCR]),
- GFP_NOFS);
+ struct_size(*ea_inode_array, inodes,
+ (*ea_inode_array)->count + EIA_INCR),
+ GFP_NOFS);
if (new_array == NULL)
return -ENOMEM;
memcpy(new_array, *ea_inode_array,
- offsetof(struct ext4_xattr_inode_array, inodes[count]));
+ struct_size(*ea_inode_array, inodes,
+ (*ea_inode_array)->count));
kfree(*ea_inode_array);
*ea_inode_array = new_array;
}
- (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode;
+ (*ea_inode_array)->count++;
+ (*ea_inode_array)->inodes[(*ea_inode_array)->count - 1] = inode;
return 0;
}
@@ -130,8 +130,8 @@ struct ext4_xattr_ibody_find {
};
struct ext4_xattr_inode_array {
- unsigned int count; /* # of used items in the array */
- struct inode *inodes[];
+ unsigned int count;
+ struct inode *inodes[] __counted_by(count);
};
extern const struct xattr_handler ext4_xattr_user_handler;
Add the __counted_by compiler attribute to the flexible array member inodes to improve access bounds-checking via CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE. Remove the now obsolete comment on the count field. In ext4_expand_inode_array(), use struct_size() instead of offsetof() and remove the local variable count. Increment the count field before adding a new inode to the inodes array. Compile-tested only. Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com> --- Changes in v2: - Adjust ext4_expand_inode_array() as suggested by Gustavo A. R. Silva - Use struct_size() and struct_size_t() instead of offsetof() - Link to v1: https://lore.kernel.org/linux-kernel/20240729110454.346918-3-thorsten.blum@toblux.com/ Changes in v3: - Use struct_size() instead of struct_size_t() as suggested by Kees Cook - Remove the local variable count as suggested by Gustavo A. R. Silva - Increment count before adding a new inode as suggested by Gustavo - Link to v2: https://lore.kernel.org/linux-kernel/20240730172301.231867-4-thorsten.blum@toblux.com/ Changes in v4: - Remove unnecessary count assignment and adjust copying the whole struct as suggested by Gustavo - Link to v3: https://lore.kernel.org/linux-kernel/20240730205509.323320-3-thorsten.blum@toblux.com/ --- fs/ext4/xattr.c | 22 ++++++++++------------ fs/ext4/xattr.h | 4 ++-- 2 files changed, 12 insertions(+), 14 deletions(-)