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authorLinus Torvalds <torvalds@linux-foundation.org>2022-08-03 14:03:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-08-03 14:03:51 -0700
commitff89dd08c0f0a3fd330c9ef9d775e880f82c291e (patch)
tree1556bd98d17b424e9a509435c118e8b9052389b7 /net
parentd9b58ab789b053b70dc475f1efda124857f10aa2 (diff)
parentf615625a44c4e641460acf74c91cedfaeab0dd28 (diff)
Merge tag 'pull-work.9p' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull 9p iov_iter fix from Al Viro: "net/9p abuses iov_iter primitives - it attempts to copy _from_ a destination-only iov_iter when it handles Rerror arriving in reply to zero-copy request. Not hard to fix, fortunately. This is a prereq for the iov_iter_get_pages() work in the second part of iov_iter series, ended up in a separate branch" * tag 'pull-work.9p' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: 9p: handling Rerror without copy_from_iter_full()
Diffstat (limited to 'net')
-rw-r--r--net/9p/client.c86
-rw-r--r--net/9p/trans_virtio.c34
2 files changed, 35 insertions, 85 deletions
diff --git a/net/9p/client.c b/net/9p/client.c
index 8bba0d9cf975..d403085b9ef5 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -550,90 +550,6 @@ out_err:
return err;
}
-/**
- * p9_check_zc_errors - check 9p packet for error return and process it
- * @c: current client instance
- * @req: request to parse and check for error conditions
- * @uidata: external buffer containing error
- * @in_hdrlen: Size of response protocol buffer.
- *
- * returns error code if one is discovered, otherwise returns 0
- *
- * this will have to be more complicated if we have multiple
- * error packet types
- */
-
-static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
- struct iov_iter *uidata, int in_hdrlen)
-{
- int err;
- int ecode;
- s8 type;
- char *ename = NULL;
-
- err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
- /* dump the response from server
- * This should be after parse_header which poplulate pdu_fcall.
- */
- trace_9p_protocol_dump(c, &req->rc);
- if (err) {
- p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
- return err;
- }
-
- if (type != P9_RERROR && type != P9_RLERROR)
- return 0;
-
- if (!p9_is_proto_dotl(c)) {
- /* Error is reported in string format */
- int len;
- /* 7 = header size for RERROR; */
- int inline_len = in_hdrlen - 7;
-
- len = req->rc.size - req->rc.offset;
- if (len > (P9_ZC_HDR_SZ - 7)) {
- err = -EFAULT;
- goto out_err;
- }
-
- ename = &req->rc.sdata[req->rc.offset];
- if (len > inline_len) {
- /* We have error in external buffer */
- if (!copy_from_iter_full(ename + inline_len,
- len - inline_len, uidata)) {
- err = -EFAULT;
- goto out_err;
- }
- }
- ename = NULL;
- err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
- &ename, &ecode);
- if (err)
- goto out_err;
-
- if (p9_is_proto_dotu(c) && ecode < 512)
- err = -ecode;
-
- if (!err) {
- err = p9_errstr2errno(ename, strlen(ename));
-
- p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
- -ecode, ename);
- }
- kfree(ename);
- } else {
- err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
- err = -ecode;
-
- p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
- }
- return err;
-
-out_err:
- p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
- return err;
-}
-
static struct p9_req_t *
p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
@@ -874,7 +790,7 @@ recalc_sigpending:
if (err < 0)
goto reterr;
- err = p9_check_zc_errors(c, req, uidata, in_hdrlen);
+ err = p9_check_errors(c, req);
trace_9p_client_res(c, type, req->rc.tag, err);
if (!err)
return req;
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index b24a4fb0f0a2..2a210c2f8e40 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -377,6 +377,35 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
}
}
+static void handle_rerror(struct p9_req_t *req, int in_hdr_len,
+ size_t offs, struct page **pages)
+{
+ unsigned size, n;
+ void *to = req->rc.sdata + in_hdr_len;
+
+ // Fits entirely into the static data? Nothing to do.
+ if (req->rc.size < in_hdr_len)
+ return;
+
+ // Really long error message? Tough, truncate the reply. Might get
+ // rejected (we can't be arsed to adjust the size encoded in header,
+ // or string size for that matter), but it wouldn't be anything valid
+ // anyway.
+ if (unlikely(req->rc.size > P9_ZC_HDR_SZ))
+ req->rc.size = P9_ZC_HDR_SZ;
+
+ // data won't span more than two pages
+ size = req->rc.size - in_hdr_len;
+ n = PAGE_SIZE - offs;
+ if (size > n) {
+ memcpy_from_page(to, *pages++, offs, n);
+ offs = 0;
+ to += n;
+ size -= n;
+ }
+ memcpy_from_page(to, *pages, offs, size);
+}
+
/**
* p9_virtio_zc_request - issue a zero copy request
* @client: client instance issuing the request
@@ -503,6 +532,11 @@ req_retry_pinned:
kicked = 1;
p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n");
err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD);
+ // RERROR needs reply (== error string) in static data
+ if (req->status == REQ_STATUS_RCVD &&
+ unlikely(req->rc.sdata[4] == P9_RERROR))
+ handle_rerror(req, in_hdr_len, offs, in_pages);
+
/*
* Non kernel buffers are pinned, unpin them
*/