Hi,
Just a polite prod in case it's fallen off the radar. The patch in this thread still applies cleanly to 4.14.15.
Thanks,
James.
On 07/12/17 01:42, James Ettle wrote:
> Patch from git as instructed:
>
>
> commit a90324ca784dea5a7259a2672c24626f5c03f576
> Author: James Ettle <james@xxxxxxxxxxxx>
> Date: Thu Dec 7 00:50:28 2017 +0000
>
> Fix unaligned access on sparc64.
>
> diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c b/net/sunrpc/auth_gss/gss_krb5_seal.c
> index 1d74d653e6c0..94a2b3f082a8 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_seal.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_seal.c
> @@ -177,6 +177,7 @@ gss_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
> u64 seq_send;
> u8 *cksumkey;
> unsigned int cksum_usage;
> + __be64 seq_send_be64;
>
> dprintk("RPC: %s\n", __func__);
>
> @@ -187,7 +188,9 @@ gss_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
> spin_lock(&krb5_seq_lock);
> seq_send = ctx->seq_send64++;
> spin_unlock(&krb5_seq_lock);
> - *((__be64 *)(krb5_hdr + 8)) = cpu_to_be64(seq_send);
> +
> + seq_send_be64 = cpu_to_be64(seq_send);
> + memcpy(krb5_hdr + 8, (char *) &seq_send_be64, 8);
>
> if (ctx->initiate) {
> cksumkey = ctx->initiator_sign;
> diff --git a/net/sunrpc/auth_gss/gss_krb5_unseal.c b/net/sunrpc/auth_gss/gss_krb5_unseal.c
> index dcf9515d9aef..8ea6e30d6f3f 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_unseal.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_unseal.c
> @@ -155,10 +155,12 @@ gss_verify_mic_v2(struct krb5_ctx *ctx,
> u8 flags;
> int i;
> unsigned int cksum_usage;
> -
> + __be16 be16_ptr;
> +
> dprintk("RPC: %s\n", __func__);
>
> - if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_MIC)
> + memcpy(&be16_ptr, (char *) ptr, 2);
> + if (be16_to_cpu(be16_ptr) != KG2_TOK_MIC)
> return GSS_S_DEFECTIVE_TOKEN;
>
> flags = ptr[2];
>
>
>
> On 06/12/17 19:09, J. Bruce Fields wrote:
>> On Sat, Dec 02, 2017 at 11:28:18PM +0000, James Ettle wrote:
>>> I've been using nfs4 with krb5 on sparc64 with kernel 4.13 and 4.14 and
>>> seeing a lot of messages like:
>>>
>>> sparky kernel: [ 105.262927] Kernel unaligned access at TPC[10afb234]
>>> gss_get_mic_kerberos+0xd4/0x360 [rpcsec_gss_krb5]
>>>
>>> I've traced this down to gss_get_mic_v2() in gss_krb5_seal.c. I think
>>> the suspicious line is:
>>>
>>> *((__be64 *)(krb5_hdr + 8)) = cpu_to_be64(seq_send);
>>>
>>> krb5_hdr is void*, but comes from a u16 so won't generally have __be64
>>> alignment. As an experiment I added local variable
>>>
>>> __be64 seq_send_be64;
>>>
>>> and replaced the cpu_to_be64 line with:
>>>
>>> seq_send_be64 = cpu_to_be64(seq_send);
>>> memcpy(krb5_hdr + 8, (char *) &seq_send_be64, 8);
>>>
>>> There's another one in gss_verify_mic_v2() in gss_krb5_unseal.c. Here
>>> there's a line
>>>
>>> if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_MIC)
>>>
>>> but ptr is a u8*. For this I added local variable
>>>
>>> __be16 data_be16;
>>>
>>> and replaced the above if() with
>>>
>>> memcpy((void *) &data_be16, (char *) ptr, 2);
>>> if (be16_to_cpu(data_be16) != KG2_TOK_MIC)
>>>
>>> I've not seen any misalignment complaints yet with this.
>>>
>>> I apologise for not sending this in the form of a patch, but this is
>>> only a sketch solution. I'm not a kernel hacker and I'm sure someone
>>> else will make a proper job of it!
>>
>> Probably so. But it might get done sooner if you do it. There's the
>> added benefit that you can test the exact patch that gets applied. You
>> can just:
>>
>> git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
>> <make your changes>
>> git commit -a
>> <write a changelog>
>>
>> then send us the output of "git show".
>>
>> --b.
>>
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