[028/101] cifs: fix possible memory corruption in CIFSFindNext
From: Greg KH <gregkh@suse.de>
Date: 2011-11-03 01:39:32
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2.6.33-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Jeff Layton <redacted> commit 9438fabb73eb48055b58b89fc51e0bc4db22fabd upstream. The name_len variable in CIFSFindNext is a signed int that gets set to the resume_name_len in the cifs_search_info. The resume_name_len however is unsigned and for some infolevels is populated directly from a 32 bit value sent by the server. If the server sends a very large value for this, then that value could look negative when converted to a signed int. That would make that value pass the PATH_MAX check later in CIFSFindNext. The name_len would then be used as a length value for a memcpy. It would then be treated as unsigned again, and the memcpy scribbles over a ton of memory. Fix this by making the name_len an unsigned value in CIFSFindNext. Reported-by: Darren Lavender <redacted> Signed-off-by: Jeff Layton <redacted> Signed-off-by: Steve French <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- fs/cifs/cifssmb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c@@ -3596,7 +3596,8 @@ int CIFSFindNext(const int xid, struct c T2_FNEXT_RSP_PARMS *parms; char *response_data; int rc = 0; - int bytes_returned, name_len; + int bytes_returned; + unsigned int name_len; __u16 params, byte_count; cFYI(1, ("In FindNext"));