From: Eugene Korenevsky <ekorenevsky@astralinux.ru>
Date: Fri, 16 Apr 2021 10:35:30 +0300
Subject: [PATCH] cifs: fix out-of-bound memory access when calling
smb3_notify() at mount point
Git-commit: a637f4ae037e1e0604ac008564934d63261a8fd1
Patch-mainline: v5.13-rc1
References: bsc#1192606
If smb3_notify() is called at mount point of CIFS, build_path_from_dentry()
returns the pointer to kmalloc-ed memory with terminating zero (this is
empty FileName to be passed to SMB2 CREATE request). This pointer is assigned
to the `path` variable.
Then `path + 1` (to skip first backslash symbol) is passed to
cifs_convert_path_to_utf16(). This is incorrect for empty path and causes
out-of-bound memory access.
Get rid of this "increase by one". cifs_convert_path_to_utf16() already
contains the check for leading backslash in the path.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=212693
CC: <stable@vger.kernel.org> # v5.6+
Signed-off-by: Eugene Korenevsky <ekorenevsky@astralinux.ru>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
fs/cifs/smb2ops.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 20f1fb66fc9e..60a474990924 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2264,7 +2264,7 @@ smb3_notify(const unsigned int xid, struct file *pfile,
goto notify_exit;
}
- utf16_path = cifs_convert_path_to_utf16(path + 1, cifs_sb);
+ utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
if (utf16_path == NULL) {
rc = -ENOMEM;
goto notify_exit;
--
2.33.1