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sunrpc: don't pass on-stack memory to sg_set_buf

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As of ac4e97abce "scatterlist: sg_set_buf() argument must be in linear
mapping", sg_set_buf hits a BUG when make_checksum_v2->xdr_process_buf,
among other callers, passes it memory on the stack.

We only need a scatterlist to pass this to the crypto code, and it seems
like overkill to require kmalloc'd memory just to encrypt a few bytes,
but for now this seems the best fix.

Many of these callers are in the NFS write paths, so we allocate with
GFP_NOFS.  It might be possible to do without allocations here entirely,
but that would probably be a bigger project.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields
2016-10-18 16:30:09 -04:00
parent 0cc11a61b8
commit 2876a34466
3 changed files with 72 additions and 46 deletions
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21
net/sunrpc/auth_gss/svcauth_gss.c
View File

@@ -718,30 +718,37 @@ gss_write_null_verf(struct svc_rqst *rqstp)
static int
gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
{
__be32 xdr_seq;
__be32 *xdr_seq;
u32 maj_stat;
struct xdr_buf verf_data;
struct xdr_netobj mic;
__be32 *p;
struct kvec iov;
int err = -1;
svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS);
xdr_seq = htonl(seq);
xdr_seq = kmalloc(4, GFP_KERNEL);
if (!xdr_seq)
return -1;
*xdr_seq = htonl(seq);
iov.iov_base = &xdr_seq;
iov.iov_len = sizeof(xdr_seq);
iov.iov_base = xdr_seq;
iov.iov_len = 4;
xdr_buf_from_iov(&iov, &verf_data);
p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
mic.data = (u8 *)(p + 1);
maj_stat = gss_get_mic(ctx_id, &verf_data, &mic);
if (maj_stat != GSS_S_COMPLETE)
return -1;
goto out;
*p++ = htonl(mic.len);
memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
p += XDR_QUADLEN(mic.len);
if (!xdr_ressize_check(rqstp, p))
return -1;
return 0;
goto out;
err = 0;
out:
kfree(xdr_seq);
return err;
}
struct gss_domain {