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SUNRPC: Fix svcauth_gss_proxy_init()

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gss_read_proxy_verf() assumes things about the XDR buffer containing
the RPC Call that are not true for buffers generated by
svc_rdma_recv().

RDMA's buffers look more like what the upper layer generates for
sending: head is a kmalloc'd buffer; it does not point to a page
whose contents are contiguous with the first page in the buffers'
page array. The result is that ACCEPT_SEC_CONTEXT via RPC/RDMA has
stopped working on Linux NFS servers that use gssproxy.

This does not affect clients that use only TCP to send their
ACCEPT_SEC_CONTEXT operation (that's all Linux clients). Other
clients, like Solaris NFS clients, send ACCEPT_SEC_CONTEXT on the
same transport as they send all other NFS operations. Such clients
can send ACCEPT_SEC_CONTEXT via RPC/RDMA.

I thought I had found every direct reference in the server RPC code
to the rqstp->rq_pages field.

Bug found at the 2019 Westford NFS bake-a-thon.

Fixes: 3316f06311 ("svcrdma: Persistently allocate and DMA- ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Bill Baker <bill.baker@oracle.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Chuck Lever 2019-10-24 09:34:16 -04:00 committed by J. Bruce Fields
parent ff27e9f748
commit 5866efa8cb
1 changed files with 63 additions and 21 deletions
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84
net/sunrpc/auth_gss/svcauth_gss.c
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@ -1078,24 +1078,32 @@ gss_read_verf(struct rpc_gss_wire_cred *gc,
return 0;
}
/* Ok this is really heavily depending on a set of semantics in
* how rqstp is set up by svc_recv and pages laid down by the
* server when reading a request. We are basically guaranteed that
* the token lays all down linearly across a set of pages, starting
* at iov_base in rq_arg.head[0] which happens to be the first of a
* set of pages stored in rq_pages[].
* rq_arg.head[0].iov_base will provide us the page_base to pass
* to the upcall.
*/
static inline int
gss_read_proxy_verf(struct svc_rqst *rqstp,
struct rpc_gss_wire_cred *gc, __be32 *authp,
struct xdr_netobj *in_handle,
struct gssp_in_token *in_token)
static void gss_free_in_token_pages(struct gssp_in_token *in_token)
{
u32 inlen;
int i;
i = 0;
inlen = in_token->page_len;
while (inlen) {
if (in_token->pages[i])
put_page(in_token->pages[i]);
inlen -= inlen > PAGE_SIZE ? PAGE_SIZE : inlen;
}
kfree(in_token->pages);
in_token->pages = NULL;
}
static int gss_read_proxy_verf(struct svc_rqst *rqstp,
struct rpc_gss_wire_cred *gc, __be32 *authp,
struct xdr_netobj *in_handle,
struct gssp_in_token *in_token)
{
struct kvec *argv = &rqstp->rq_arg.head[0];
u32 inlen;
int res;
unsigned int page_base, length;
int pages, i, res;
size_t inlen;
res = gss_read_common_verf(gc, argv, authp, in_handle);
if (res)
@ -1105,10 +1113,36 @@ gss_read_proxy_verf(struct svc_rqst *rqstp,
if (inlen > (argv->iov_len + rqstp->rq_arg.page_len))
return SVC_DENIED;
in_token->pages = rqstp->rq_pages;
in_token->page_base = (ulong)argv->iov_base & ~PAGE_MASK;
pages = DIV_ROUND_UP(inlen, PAGE_SIZE);
in_token->pages = kcalloc(pages, sizeof(struct page *), GFP_KERNEL);
if (!in_token->pages)
return SVC_DENIED;
in_token->page_base = 0;
in_token->page_len = inlen;
for (i = 0; i < pages; i++) {
in_token->pages[i] = alloc_page(GFP_KERNEL);
if (!in_token->pages[i]) {
gss_free_in_token_pages(in_token);
return SVC_DENIED;
}
}
length = min_t(unsigned int, inlen, argv->iov_len);
memcpy(page_address(in_token->pages[0]), argv->iov_base, length);
inlen -= length;
i = 1;
page_base = rqstp->rq_arg.page_base;
while (inlen) {
length = min_t(unsigned int, inlen, PAGE_SIZE);
memcpy(page_address(in_token->pages[i]),
page_address(rqstp->rq_arg.pages[i]) + page_base,
length);
inlen -= length;
page_base = 0;
i++;
}
return 0;
}
@ -1282,8 +1316,11 @@ static int svcauth_gss_proxy_init(struct svc_rqst *rqstp,
break;
case GSS_S_COMPLETE:
status = gss_proxy_save_rsc(sn->rsc_cache, &ud, &handle);
if (status)
if (status) {
pr_info("%s: gss_proxy_save_rsc failed (%d)\n",
__func__, status);
goto out;
}
cli_handle.data = (u8 *)&handle;
cli_handle.len = sizeof(handle);
break;
@ -1294,15 +1331,20 @@ static int svcauth_gss_proxy_init(struct svc_rqst *rqstp,
/* Got an answer to the upcall; use it: */
if (gss_write_init_verf(sn->rsc_cache, rqstp,
&cli_handle, &ud.major_status))
&cli_handle, &ud.major_status)) {
pr_info("%s: gss_write_init_verf failed\n", __func__);
goto out;
}
if (gss_write_resv(resv, PAGE_SIZE,
&cli_handle, &ud.out_token,
ud.major_status, ud.minor_status))
ud.major_status, ud.minor_status)) {
pr_info("%s: gss_write_resv failed\n", __func__);
goto out;
}
ret = SVC_COMPLETE;
out:
gss_free_in_token_pages(&ud.in_token);
gssp_free_upcall_data(&ud);
return ret;
}