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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