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rpc: fix huge kmalloc's in gss-proxy

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The reply to a gssproxy can include up to NGROUPS_MAX gid's, which will
take up more than a page.  We therefore need to allocate an array of
pages to hold the reply instead of trying to allocate a single huge
buffer.

Tested-by: Simo Sorce <simo@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2013-08-20 18:13:27 -04:00
commit 9dfd87da1a
3 changed files with 37 additions and 1 deletions
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30
net/sunrpc/auth_gss/gss_rpc_upcall.c
View file

@ -213,6 +213,30 @@ static int gssp_call(struct net *net, struct rpc_message *msg)
return status;
}
static void gssp_free_receive_pages(struct gssx_arg_accept_sec_context *arg)
{
int i;
for (i = 0; i < arg->npages && arg->pages[i]; i++)
__free_page(arg->pages[i]);
}
static int gssp_alloc_receive_pages(struct gssx_arg_accept_sec_context *arg)
{
int i;
arg->npages = DIV_ROUND_UP(NGROUPS_MAX * 4, PAGE_SIZE);
arg->pages = kzalloc(arg->npages * sizeof(struct page *), GFP_KERNEL);
for (i=0; i < arg->npages; i++) {
arg->pages[i] = alloc_page(GFP_KERNEL);
if (arg->pages[i] == NULL) {
gssp_free_receive_pages(arg);
return -ENOMEM;
}
}
return 0;
}
/*
* Public functions
@ -261,10 +285,16 @@ int gssp_accept_sec_context_upcall(struct net *net,
arg.context_handle = &ctxh;
res.output_token->len = GSSX_max_output_token_sz;
ret = gssp_alloc_receive_pages(&arg);
if (ret)
return ret;
/* use nfs/ for targ_name ? */
ret = gssp_call(net, &msg);
gssp_free_receive_pages(&arg);
/* we need to fetch all data even in case of error so
* that we can free special strctures is they have been allocated */
data->major_status = res.status.major_status;

3
net/sunrpc/auth_gss/gss_rpc_xdr.c
View file

@ -780,6 +780,9 @@ void gssx_enc_accept_sec_context(struct rpc_rqst *req,
/* arg->options */
err = dummy_enc_opt_array(xdr, &arg->options);
xdr_inline_pages(&req->rq_rcv_buf,
PAGE_SIZE/2 /* pretty arbitrary */,
arg->pages, 0 /* page base */, arg->npages * PAGE_SIZE);
done:
if (err)
dprintk("RPC: gssx_enc_accept_sec_context: %d\n", err);

5
net/sunrpc/auth_gss/gss_rpc_xdr.h
View file

@ -147,6 +147,8 @@ struct gssx_arg_accept_sec_context {
struct gssx_cb *input_cb;
u32 ret_deleg_cred;
struct gssx_option_array options;
struct page **pages;
unsigned int npages;
};
struct gssx_res_accept_sec_context {
@ -240,7 +242,8 @@ int gssx_dec_accept_sec_context(struct rpc_rqst *rqstp,
2 * GSSX_max_princ_sz + \
8 + 8 + 4 + 4 + 4)
#define GSSX_max_output_token_sz 1024
#define GSSX_max_creds_sz (4 + 4 + 4 + NGROUPS_MAX * 4)
/* grouplist not included; we allocate separate pages for that: */
#define GSSX_max_creds_sz (4 + 4 + 4 /* + NGROUPS_MAX*4 */)
#define GSSX_RES_accept_sec_context_sz (GSSX_default_status_sz + \
GSSX_default_ctx_sz + \
GSSX_max_output_token_sz + \