We can't use PATH_MAX for SMB symlinks because
(1) Windows Server will fail FSCTL_SET_REPARSE_POINT with
STATUS_IO_REPARSE_DATA_INVALID when input buffer is larger than
16K, as specified in MS-FSA 2.1.5.10.37.
(2) The client won't be able to parse large SMB responses that
includes SMB symlink path within SMB2_CREATE or SMB2_IOCTL
responses.
Fix this by defining a maximum length value (4060) for SMB symlinks
that both client and server can handle.
Cc: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@xxxxxxxxxxxxx>
---
fs/smb/client/reparse.c | 5 ++++-
fs/smb/client/reparse.h | 2 ++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c
index 74abbdf5026c..90da1e2b6217 100644
--- a/fs/smb/client/reparse.c
+++ b/fs/smb/client/reparse.c
@@ -35,6 +35,9 @@ int smb2_create_reparse_symlink(const unsigned int xid, struct inode *inode,
u16 len, plen;
int rc = 0;
+ if (strlen(symname) > REPARSE_SYM_PATH_MAX)
+ return -ENAMETOOLONG;
+
sym = kstrdup(symname, GFP_KERNEL);
if (!sym)
return -ENOMEM;
@@ -64,7 +67,7 @@ int smb2_create_reparse_symlink(const unsigned int xid, struct inode *inode,
if (rc < 0)
goto out;
- plen = 2 * UniStrnlen((wchar_t *)path, PATH_MAX);
+ plen = 2 * UniStrnlen((wchar_t *)path, REPARSE_SYM_PATH_MAX);
len = sizeof(*buf) + plen * 2;
buf = kzalloc(len, GFP_KERNEL);
if (!buf) {
diff --git a/fs/smb/client/reparse.h b/fs/smb/client/reparse.h
index 158e7b7aae64..2a9f4f9f79de 100644
--- a/fs/smb/client/reparse.h
+++ b/fs/smb/client/reparse.h
@@ -12,6 +12,8 @@
#include "fs_context.h"
#include "cifsglob.h"
+#define REPARSE_SYM_PATH_MAX 4060
+
/*
* Used only by cifs.ko to ignore reparse points from files when client or
* server doesn't support FSCTL_GET_REPARSE_POINT.
--
2.47.0
