On Tue, Nov 07, 2023 at 02:37:17AM +0000, Dmitry Safonov wrote:
> The cloned child of ahash that uses shash under the hood should use
> shash helpers (like crypto_shash_setkey()).
>
> The following panic may be observed on TCP-AO selftests:
>
> > ==================================================================
> > BUG: KASAN: wild-memory-access in crypto_mod_get+0x1b/0x60
> > Write of size 4 at addr 5d5be0ff5c415e14 by task connect_ipv4/1397
> >
> > CPU: 0 PID: 1397 Comm: connect_ipv4 Tainted: G W 6.6.0+ #47
> > Call Trace:
> > <TASK>
> > dump_stack_lvl+0x46/0x70
> > kasan_report+0xc3/0xf0
> > kasan_check_range+0xec/0x190
> > crypto_mod_get+0x1b/0x60
> > crypto_spawn_alg+0x53/0x140
> > crypto_spawn_tfm2+0x13/0x60
> > hmac_init_tfm+0x25/0x60
> > crypto_ahash_setkey+0x8b/0x100
> > tcp_ao_add_cmd+0xe7a/0x1120
> > do_tcp_setsockopt+0x5ed/0x12a0
> > do_sock_setsockopt+0x82/0x100
> > __sys_setsockopt+0xe9/0x160
> > __x64_sys_setsockopt+0x60/0x70
> > do_syscall_64+0x3c/0xe0
> > entry_SYSCALL_64_after_hwframe+0x46/0x4e
> > ==================================================================
> > general protection fault, probably for non-canonical address 0x5d5be0ff5c415e14: 0000 [#1] PREEMPT SMP KASAN
> > CPU: 0 PID: 1397 Comm: connect_ipv4 Tainted: G B W 6.6.0+ #47
> > Call Trace:
> > <TASK>
> > ? die_addr+0x3c/0xa0
> > ? exc_general_protection+0x144/0x210
> > ? asm_exc_general_protection+0x22/0x30
> > ? add_taint+0x26/0x90
> > ? crypto_mod_get+0x20/0x60
> > ? crypto_mod_get+0x1b/0x60
> > ? ahash_def_finup_done1+0x58/0x80
> > crypto_spawn_alg+0x53/0x140
> > crypto_spawn_tfm2+0x13/0x60
> > hmac_init_tfm+0x25/0x60
> > crypto_ahash_setkey+0x8b/0x100
> > tcp_ao_add_cmd+0xe7a/0x1120
> > do_tcp_setsockopt+0x5ed/0x12a0
> > do_sock_setsockopt+0x82/0x100
> > __sys_setsockopt+0xe9/0x160
> > __x64_sys_setsockopt+0x60/0x70
> > do_syscall_64+0x3c/0xe0
> > entry_SYSCALL_64_after_hwframe+0x46/0x4e
> > </TASK>
> > RIP: 0010:crypto_mod_get+0x20/0x60
>
> Make sure that the child/clone has using_shash set when parent is
> an shash user.
>
> Fixes: 2f1f34c1bf7b ("crypto: ahash - optimize performance when wrapping shash")
> Cc: David Ahern <dsahern@xxxxxxxxxx>
> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> Cc: Dmitry Safonov <0x7f454c46@xxxxxxxxx>
> Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> Cc: Francesco Ruggeri <fruggeri05@xxxxxxxxx>
> To: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> Cc: Salam Noureddine <noureddine@xxxxxxxxxx>
> Cc: netdev@xxxxxxxxxxxxxxx
> Cc: linux-crypto@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx>
> ---
> crypto/ahash.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/crypto/ahash.c b/crypto/ahash.c
> index deee55f939dc..80c3e5354711 100644
> --- a/crypto/ahash.c
> +++ b/crypto/ahash.c
> @@ -651,6 +651,7 @@ struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
> err = PTR_ERR(shash);
> goto out_free_nhash;
> }
> + nhash->using_shash = true;
> *nctx = shash;
> return nhash;
> }
>
> base-commit: be3ca57cfb777ad820c6659d52e60bbdd36bf5ff
Thanks:
Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Note that this bug would have been prevented if crypto_clone_*() were covered by
the crypto self-tests.
- Eric
