On Fri, 2022-05-27 at 19:17 +0800, Xiu Jianfeng wrote:
> This reverts commit ccf11dbaa07b328fa469415c362d33459c140a37.
>
> Commit ccf11dbaa07b ("evm: Fix memleak in init_desc") said there is
> memleak in init_desc. That may be incorrect, as we can see, tmp_tfm is
> saved in one of the two global variables hmac_tfm ohr evm_tfm[hash_algo],
> then if init_desc is called next time, there is no need to alloc tfm
> again, so in the error path of kmalloc desc or crypto_shash_init(desc),
> It is not a problem without freeing tmp_tfm.
>
> And also that commit did not reset the global variable to NULL after
> freeing tmp_tfm and this makes *tfm a dangling pointer which may cause a
> UAF issue.
>
> Signed-off-by: Xiu Jianfeng <[email protected]>
Agreed, thanks. This was first reported by Guozihua (Scott) <
[email protected]>. If neither you nor Scott object, I'll add his
Reported-by tag.
thanks,
Mimi