Re: [PATCH v2 2/2] ima: Alloc ima_max_digest_data in xattr_verify() if CONFIG_VMAP_STACK=y

On Thu, Dec 01, 2022 at 11:06:25AM +0100, Roberto Sassu wrote:

From: Roberto Sassu roberto.sassu@huawei.com

Similarly to evm_verify_hmac(), which allocates an evm_digest structure to satisfy the linear mapping requirement if CONFIG_VMAP_STACK is enabled, do the same in xattr_verify(). Allocate an ima_max_digest_data structure and use that instead of the in-stack counterpart.

Cc: stable@vger.kernel.org # 4.9.x Fixes: ba14a194a434 ("fork: Add generic vmalloced stack support") Signed-off-by: Roberto Sassu roberto.sassu@huawei.com

Likewise, what is the actual problem here? Where specifically is a scatterlist being used to represent an on-stack buffer?

- Eric