diff options
| -rw-r--r-- | source3/smbd/process.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/source3/smbd/process.c b/source3/smbd/process.c index f542dcd84f..6d391df4e0 100644 --- a/source3/smbd/process.c +++ b/source3/smbd/process.c @@ -2025,15 +2025,24 @@ void chain_reply(struct smb_request *req) SMB_PERFCOUNT_SET_MSGLEN_IN(&req->pcd, smblen); /* - * Check if the client tries to fool us. The request so far uses the - * space to the end of the byte buffer in the request just - * processed. The chain_offset can't point into that area. If that was - * the case, we could end up with an endless processing of the chain, - * we would always handle the same request. + * Check if the client tries to fool us. The chain offset + * needs to point beyond the current request in the chain, it + * needs to strictly grow. Otherwise we might be tricked into + * an endless loop always processing the same request over and + * over again. We used to assume that vwv and the byte buffer + * array in a chain are always attached, but OS/2 the + * Write&X/Read&X chain puts the Read&X vwv array right behind + * the Write&X vwv chain. The Write&X bcc array is put behind + * the Read&X vwv array. So now we check whether the chain + * offset points strictly behind the previous vwv + * array. req->buf points right after the vwv array of the + * previous request. See + * https://bugzilla.samba.org/show_bug.cgi?id=8360 for more + * information. */ - already_used = PTR_DIFF(req->buf+req->buflen, smb_base(req->inbuf)); - if (chain_offset < already_used) { + already_used = PTR_DIFF(req->buf, smb_base(req->inbuf)); + if (chain_offset <= already_used) { goto error; } |