Re: [PATCH] x86/microcode/AMD: fix memleak in update_cache()

[Borislav Petkov]

On Wed, Jul 19, 2017 at 12:21:23PM +0800, shuwang@xxxxxxxxxx wrote:
> From: Shu Wang <shuwang@xxxxxxxxxx>
> 
> Found this issue by kmemleak. The mem is allocated in
> verify_and_add_patch(), passed to update_cache(patch),
> and just dropped the reference without free
> if (p->patch_id >= new_patch->patch_id)
>     return;
> 
> unreferenced object 0xffff88010e780b40 (size 32):
>   comm "bash", pid 860, jiffies 4294690939 (age 29.297s)
>   backtrace:
>     [<ffffffff8176166a>] kmemleak_alloc+0x4a/0xa0
>     [<ffffffff8121801a>] kmem_cache_alloc_trace+0xca/0x1d0
>     [<ffffffff81050d60>] load_microcode_amd.isra.0+0x1d0/0x400
>     [<ffffffff81051053>] request_microcode_amd+0xc3/0x160
>     [<ffffffff8104eef1>] reload_store+0xe1/0x170
>     [<ffffffff814dd228>] dev_attr_store+0x18/0x30
>     [<ffffffff812ce8ca>] sysfs_kf_write+0x3a/0x50
>     [<ffffffff812ce38f>] kernfs_fop_write+0xff/0x180
>     [<ffffffff81242307>] __vfs_write+0x37/0x170
>     [<ffffffff81243892>] vfs_write+0xb2/0x1b0
>     [<ffffffff81244ec5>] SyS_write+0x55/0xc0
>     [<ffffffff81003857>] do_syscall_64+0x67/0x150
>     [<ffffffff8176d3e7>] return_from_SYSCALL_64+0x0/0x6a
>     [<ffffffffffffffff>] 0xffffffffffffffff
> 
> (gdb) list *0xffffffff81050d60
> 0xffffffff81050d60 is in load_microcode_amd
>               (arch/x86/kernel/cpu/microcode/amd.c:616).
> 
> Signed-off-by: Shu Wang <shuwang@xxxxxxxxxx>
> ---
>  arch/x86/kernel/cpu/microcode/amd.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

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