Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).
While there, use struct_size() helper, instead of the open-coded version, to calculate the size for the allocation of the whole flexible structure, including of course, the flexible-array member. This code was found with the help of Coccinelle, and audited and fixed manually. Signed-off-by: Gustavo A. R. Silva <[email protected]> --- fs/afs/internal.h | 2 +- fs/afs/xattr.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 469a717467a4..e263a58b82ba 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -1116,7 +1116,7 @@ extern void afs_fs_inline_bulk_status(struct afs_operation *); struct afs_acl { u32 size; - u8 data[]; + u8 data[] __counted_by(size); }; extern void afs_fs_fetch_acl(struct afs_operation *); diff --git a/fs/afs/xattr.c b/fs/afs/xattr.c index 9048d8ccc715..8b42cac51660 100644 --- a/fs/afs/xattr.c +++ b/fs/afs/xattr.c @@ -75,7 +75,7 @@ static bool afs_make_acl(struct afs_operation *op, { struct afs_acl *acl; - acl = kmalloc(sizeof(*acl) + size, GFP_KERNEL); + acl = kmalloc(struct_size(acl, data, size), GFP_KERNEL); if (!acl) { afs_op_nomem(op); return false; -- 2.34.1
