Re: [PATCH v2 05/11] hw/misc/aspeed_hace: Do not crash if address_space_map() failed

["Cédric Le Goater" <clg@kaod.org>]

On 12/30/22 12:34, Philippe Mathieu-Daudé wrote:
> address_space_map() can fail:
> 
>    uart:~$ hash test
>    sha256_test
>    tv[0]:
>    Segmentation fault: 11
>    Thread 3 "qemu-system-arm" received signal SIGSEGV, Segmentation fault.
>    gen_acc_mode_iov (req_len=0x7ffff18b7778, id=<optimized out>, iov=0x7ffff18b7780, s=0x555556ce0bd0)
>        at ../hw/misc/aspeed_hace.c:171
>    171         if (has_padding(s, &iov[id], *req_len, &total_msg_len, &pad_offset)) {
>    (gdb) bt
>    #0  gen_acc_mode_iov (req_len=0x7ffff18b7778, id=<optimized out>, iov=0x7ffff18b7780, s=0x555556ce0bd0)
>        at ../hw/misc/aspeed_hace.c:171
>    #1  do_hash_operation (s=s@entry=0x555556ce0bd0, algo=3, sg_mode=sg_mode@entry=true, acc_mode=acc_mode@entry=true)
>        at ../hw/misc/aspeed_hace.c:224
>    #2  0x00005555559bdbb8 in aspeed_hace_write (opaque=<optimized out>, addr=12, data=262488, size=<optimized out>)
>        at ../hw/misc/aspeed_hace.c:358
> 
> This change doesn't fix much, but at least the guest
> can't crash QEMU anymore. Instead it is still usable:
> 
>    uart:~$ hash test
>    sha256_test
>    tv[0]:hash_final error
>    sha384_test
>    tv[0]:hash_final error
>    sha512_test
>    tv[0]:hash_final error
>    [00:00:06.278,000] <err> hace_global: HACE poll timeout
>    [00:00:09.324,000] <err> hace_global: HACE poll timeout
>    [00:00:12.261,000] <err> hace_global: HACE poll timeout
>    uart:~$
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Reviewed-by: Peter Delevoryas <peter@pjd.dev>

This is a tough model. I am glad you are taking a look at it.

Reviewed-by: Cédric Le Goater <clg@kaod.org>

Thanks,

C.

> ---
>   hw/misc/aspeed_hace.c | 21 +++++++++++++++------
>   1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/misc/aspeed_hace.c b/hw/misc/aspeed_hace.c
> index ac21be306c..12a761f1f5 100644
> --- a/hw/misc/aspeed_hace.c
> +++ b/hw/misc/aspeed_hace.c
> @@ -193,6 +193,7 @@ static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode,
>       size_t digest_len = 0;
>       int niov = 0;
>       int i;
> +    void *haddr;
>   
>       if (sg_mode) {
>           uint32_t len = 0;
> @@ -217,9 +218,13 @@ static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode,
>               addr &= SG_LIST_ADDR_MASK;
>   
>               plen = len & SG_LIST_LEN_MASK;
> -            iov[i].iov_base = address_space_map(&s->dram_as, addr, &plen, false,
> -                                                MEMTXATTRS_UNSPECIFIED);
> -
> +            haddr = address_space_map(&s->dram_as, addr, &plen, false,
> +                                      MEMTXATTRS_UNSPECIFIED);
> +            if (haddr == NULL) {
> +                qemu_log_mask(LOG_GUEST_ERROR, "%s: qcrypto failed\n", __func__);
> +                return;
> +            }
> +            iov[i].iov_base = haddr;
>               if (acc_mode) {
>                   niov = gen_acc_mode_iov(s, iov, i, &plen);
>   
> @@ -230,10 +235,14 @@ static void do_hash_operation(AspeedHACEState *s, int algo, bool sg_mode,
>       } else {
>           hwaddr len = s->regs[R_HASH_SRC_LEN];
>   
> +        haddr = address_space_map(&s->dram_as, s->regs[R_HASH_SRC],
> +                                  &len, false, MEMTXATTRS_UNSPECIFIED);
> +        if (haddr == NULL) {
> +            qemu_log_mask(LOG_GUEST_ERROR, "%s: qcrypto failed\n", __func__);
> +            return;
> +        }
> +        iov[0].iov_base = haddr;
>           iov[0].iov_len = len;
> -        iov[0].iov_base = address_space_map(&s->dram_as, s->regs[R_HASH_SRC],
> -                                            &len, false,
> -                                            MEMTXATTRS_UNSPECIFIED);
>           i = 1;
>   
>           if (s->iov_count) {