Allow to decrypt transformed packets that are bigger than the big
buffer size. In particular it is used for read responses that can
only exceed the big buffer size.
Signed-off-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
---
fs/cifs/cifsproto.h | 1 +
fs/cifs/cifssmb.c | 8 +--
fs/cifs/smb2ops.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++---
3 files changed, 169 insertions(+), 13 deletions(-)
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 0eb35d2..0dbafc8 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -76,6 +76,7 @@ extern void cifs_delete_mid(struct mid_q_entry *mid);
extern void cifs_wake_up_task(struct mid_q_entry *mid);
extern int cifs_handle_standard(struct TCP_Server_Info *server,
struct mid_q_entry *mid);
+extern int cifs_discard_remaining_data(struct TCP_Server_Info *server);
extern int cifs_call_async(struct TCP_Server_Info *server,
struct smb_rqst *rqst,
mid_receive_t *receive, mid_callback_t *callback,
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 8326212..5d9ad38 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1399,8 +1399,8 @@ CIFS_open(const unsigned int xid, struct cifs_open_parms *oparms, int *oplock,
* Discard any remaining data in the current SMB. To do this, we borrow the
* current bigbuf.
*/
-static int
-discard_remaining_data(struct TCP_Server_Info *server)
+int
+cifs_discard_remaining_data(struct TCP_Server_Info *server)
{
unsigned int rfclen = get_rfc1002_length(server->smallbuf);
int remaining = rfclen + 4 - server->total_read;
@@ -1426,7 +1426,7 @@ cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
int length;
struct cifs_readdata *rdata = mid->callback_data;
- length = discard_remaining_data(server);
+ length = cifs_discard_remaining_data(server);
dequeue_mid(mid, rdata->result);
return length;
}
@@ -1459,7 +1459,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
if (server->ops->is_status_pending &&
server->ops->is_status_pending(buf, server, 0)) {
- discard_remaining_data(server);
+ cifs_discard_remaining_data(server);
return -1;
}
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 86b8ab2..0764c32 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1844,12 +1844,72 @@ decrypt_raw_data(struct TCP_Server_Info *server, char *buf,
}
static int
+read_data_into_pages(struct TCP_Server_Info *server, struct page **pages,
+ unsigned int npages, unsigned int len)
+{
+ int i;
+ int length;
+
+ for (i = 0; i < npages; i++) {
+ struct page *page = pages[i];
+ size_t n;
+
+ n = len;
+ if (len >= PAGE_SIZE) {
+ /* enough data to fill the page */
+ n = PAGE_SIZE;
+ len -= n;
+ } else {
+ zero_user(page, len, PAGE_SIZE - len);
+ len = 0;
+ }
+ length = cifs_read_page_from_socket(server, page, n);
+ if (length < 0)
+ return length;
+ server->total_read += length;
+ }
+
+ return 0;
+}
+
+static int
+init_read_bvec(struct page **pages, unsigned int npages, unsigned int data_size,
+ unsigned int cur_off, struct bio_vec **page_vec)
+{
+ struct bio_vec *bvec;
+ int i;
+
+ bvec = kcalloc(npages, sizeof(struct bio_vec), GFP_KERNEL);
+ if (!bvec)
+ return -ENOMEM;
+
+ for (i = 0; i < npages; i++) {
+ bvec[i].bv_page = pages[i];
+ bvec[i].bv_offset = (i == 0) ? cur_off : 0;
+ bvec[i].bv_len = min_t(unsigned int, PAGE_SIZE, data_size);
+ data_size -= bvec[i].bv_len;
+ }
+
+ if (data_size != 0) {
+ cifs_dbg(VFS, "%s: something went wrong\n", __func__);
+ kfree(bvec);
+ return -EIO;
+ }
+
+ *page_vec = bvec;
+ return 0;
+}
+
+static int
handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
char *buf, unsigned int buf_len, struct page **pages,
unsigned int npages, unsigned int page_data_size)
{
unsigned int data_offset;
unsigned int data_len;
+ unsigned int cur_off;
+ unsigned int cur_page_idx;
+ unsigned int pad_len;
struct cifs_readdata *rdata = mid->callback_data;
struct smb2_sync_hdr *shdr = get_sync_hdr(buf);
struct bio_vec *bvec = NULL;
@@ -1895,9 +1955,37 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
return 0;
}
+ pad_len = data_offset - server->vals->read_rsp_size;
+
if (buf_len <= data_offset) {
/* read response payload is in pages */
- /* BB add code to init iter with pages */
+ cur_page_idx = pad_len / PAGE_SIZE;
+ cur_off = pad_len % PAGE_SIZE;
+
+ if (cur_page_idx != 0) {
+ /* data offset is beyond the 1st page of response */
+ cifs_dbg(FYI, "%s: data offset (%u) beyond 1st page of response\n",
+ __func__, data_offset);
+ rdata->result = -EIO;
+ dequeue_mid(mid, rdata->result);
+ return 0;
+ }
+
+ if (data_len > page_data_size - pad_len) {
+ /* data_len is corrupt -- discard frame */
+ rdata->result = -EIO;
+ dequeue_mid(mid, rdata->result);
+ return 0;
+ }
+
+ rdata->result = init_read_bvec(pages, npages, page_data_size,
+ cur_off, &bvec);
+ if (rdata->result != 0) {
+ dequeue_mid(mid, rdata->result);
+ return 0;
+ }
+
+ iov_iter_bvec(&iter, WRITE | ITER_BVEC, bvec, npages, data_len);
} else if (buf_len >= data_offset + data_len) {
/* read response payload is in buf */
WARN_ONCE(npages > 0, "read data can be either in buf or in pages");
@@ -1932,6 +2020,79 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
}
static int
+receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid)
+{
+ char *buf = server->smallbuf;
+ struct smb2_transform_hdr *tr_hdr = (struct smb2_transform_hdr *)buf;
+ unsigned int npages;
+ struct page **pages;
+ unsigned int len;
+ unsigned int buflen = get_rfc1002_length(buf) + 4;
+ int rc;
+ int i = 0;
+
+ len = min_t(unsigned int, buflen, server->vals->read_rsp_size - 4 +
+ sizeof(struct smb2_transform_hdr)) - HEADER_SIZE(server) + 1;
+
+ rc = cifs_read_from_socket(server, buf + HEADER_SIZE(server) - 1, len);
+ if (rc < 0)
+ return rc;
+ server->total_read += rc;
+
+ len = le32_to_cpu(tr_hdr->OriginalMessageSize) + 4 -
+ server->vals->read_rsp_size;
+ npages = DIV_ROUND_UP(len, PAGE_SIZE);
+
+ pages = kmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
+ if (!pages) {
+ rc = -ENOMEM;
+ goto discard_data;
+ }
+
+ for (; i < npages; i++) {
+ pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
+ if (!pages[i]) {
+ rc = -ENOMEM;
+ goto discard_data;
+ }
+ }
+
+ /* read read data into pages */
+ rc = read_data_into_pages(server, pages, npages, len);
+ if (rc)
+ goto free_pages;
+
+ rc = cifs_discard_remaining_data(server);
+ if (rc)
+ goto free_pages;
+
+ rc = decrypt_raw_data(server, buf, server->vals->read_rsp_size - 4,
+ pages, npages, len);
+ if (rc)
+ goto free_pages;
+
+ *mid = smb2_find_mid(server, buf);
+ if (*mid == NULL)
+ cifs_dbg(FYI, "mid not found\n");
+ else {
+ cifs_dbg(FYI, "mid found\n");
+ (*mid)->decrypted = true;
+ rc = handle_read_data(server, *mid, buf,
+ server->vals->read_rsp_size,
+ pages, npages, len);
+ }
+
+free_pages:
+ for (i = i - 1; i >= 0; i--)
+ put_page(pages[i]);
+ kfree(pages);
+ return rc;
+discard_data:
+ cifs_discard_remaining_data(server);
+ goto free_pages;
+}
+
+static int
receive_encrypted_standard(struct TCP_Server_Info *server,
struct mid_q_entry **mid)
{
@@ -2000,14 +2161,8 @@ smb3_receive_transform(struct TCP_Server_Info *server, struct mid_q_entry **mid)
return -ECONNABORTED;
}
- if (pdu_length + 4 > CIFSMaxBufSize + MAX_HEADER_SIZE(server)) {
- cifs_dbg(VFS, "Decoding responses of big size (%u) is not supported\n",
- pdu_length);
- /* BB add code to allocate and fill highmem pages here */
- cifs_reconnect(server);
- wake_up(&server->response_q);
- return -ECONNABORTED;
- }
+ if (pdu_length + 4 > CIFSMaxBufSize + MAX_HEADER_SIZE(server))
+ return receive_encrypted_read(server, mid);
return receive_encrypted_standard(server, mid);
}
--
2.7.4
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