When enumerating snapshots, the last few bytes of the final
snapshot could be left off since we were miscalculating the
length returned (leaving off the sizeof struct SRV_SNAPSHOT_ARRAY)
See MS-SMB2 section 2.2.32.2. In addition fixup the length used
to allow smaller buffer to be passed in, in order to allow
returning the size of the whole snapshot array more easily.
CC: Stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 15c7cbde2f39..abd6142e1b4a 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1369,6 +1369,8 @@ smb3_set_integrity(const unsigned int xid,
struct cifs_tcon *tcon,
}
+/* GMT Token is @GMT-YYYY.MM.DD-HH.MM.SS Unicode which is 48 bytes + null */
+#define GMT_TOKEN_SIZE 50
static int
smb3_enum_snapshots(const unsigned int xid, struct cifs_tcon *tcon,
struct cifsFileInfo *cfile, void __user *ioc_buf)
@@ -1398,14 +1400,25 @@ smb3_enum_snapshots(const unsigned int xid,
struct cifs_tcon *tcon,
kfree(retbuf);
return rc;
}
- if (snapshot_in.snapshot_array_size < sizeof(struct
smb_snapshot_array)) {
- rc = -ERANGE;
- kfree(retbuf);
- return rc;
- }
- if (ret_data_len > snapshot_in.snapshot_array_size)
- ret_data_len = snapshot_in.snapshot_array_size;
+ /* check for min size, ie not large enough to fit even one GMT
+ * token (snapshot). On the first ioctl some users may pass in
+ * smaller size (or zero) to simply get the size of the array
+ * so the user space caller can allocate sufficient memory
+ * and retry the ioctl again with larger array size sufficient
+ * to hold all of the snapshot GMT tokens on the second try.
+ */
+ if (snapshot_in.snapshot_array_size < GMT_TOKEN_SIZE)
+ ret_data_len = sizeof(struct smb_snapshot_array);
+
+ /* we return struct SRV_SNAPSHOT_ARRAY, followed by
+ * the snapshot array (of 50 byte GMT tokens) each
+ * representing an available previous version of the data
+ */
+ if (ret_data_len > (snapshot_in.snapshot_array_size +
+ sizeof(struct smb_snapshot_array)))
+ ret_data_len = snapshot_in.snapshot_array_size +
+ sizeof(struct smb_snapshot_array);
if (copy_to_user(ioc_buf, retbuf, ret_data_len))
rc = -EFAULT;
(END)
--
Thanks,
Steve
From b505088cfa0c22b4cc1bbed08b72c9bdf16c8522 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Thu, 9 Aug 2018 00:51:34 -0500
Subject: [PATCH] smb3: enumerating snapshots was leaving part of the data off
end
When enumerating snapshots, the last few bytes of the final
snapshot could be left off since we were miscalculating the
length returned (leaving off the sizeof struct SRV_SNAPSHOT_ARRAY)
See MS-SMB2 section 2.2.32.2. In addition fixup the length used
to allow smaller buffer to be passed in, in order to allow
returning the size of the whole snapshot array more easily.
CC: Stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/cifs/smb2ops.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 15c7cbde2f39..abd6142e1b4a 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1369,6 +1369,8 @@ smb3_set_integrity(const unsigned int xid, struct cifs_tcon *tcon,
}
+/* GMT Token is @GMT-YYYY.MM.DD-HH.MM.SS Unicode which is 48 bytes + null */
+#define GMT_TOKEN_SIZE 50
static int
smb3_enum_snapshots(const unsigned int xid, struct cifs_tcon *tcon,
struct cifsFileInfo *cfile, void __user *ioc_buf)
@@ -1398,14 +1400,25 @@ smb3_enum_snapshots(const unsigned int xid, struct cifs_tcon *tcon,
kfree(retbuf);
return rc;
}
- if (snapshot_in.snapshot_array_size < sizeof(struct smb_snapshot_array)) {
- rc = -ERANGE;
- kfree(retbuf);
- return rc;
- }
- if (ret_data_len > snapshot_in.snapshot_array_size)
- ret_data_len = snapshot_in.snapshot_array_size;
+ /* check for min size, ie not large enough to fit even one GMT
+ * token (snapshot). On the first ioctl some users may pass in
+ * smaller size (or zero) to simply get the size of the array
+ * so the user space caller can allocate sufficient memory
+ * and retry the ioctl again with larger array size sufficient
+ * to hold all of the snapshot GMT tokens on the second try.
+ */
+ if (snapshot_in.snapshot_array_size < GMT_TOKEN_SIZE)
+ ret_data_len = sizeof(struct smb_snapshot_array);
+
+ /* we return struct SRV_SNAPSHOT_ARRAY, followed by
+ * the snapshot array (of 50 byte GMT tokens) each
+ * representing an available previous version of the data
+ */
+ if (ret_data_len > (snapshot_in.snapshot_array_size +
+ sizeof(struct smb_snapshot_array)))
+ ret_data_len = snapshot_in.snapshot_array_size +
+ sizeof(struct smb_snapshot_array);
if (copy_to_user(ioc_buf, retbuf, ret_data_len))
rc = -EFAULT;
--
2.17.1
