SMB: fix leak of validate negotiate info response buffer

commit fe83bebc05228e838ed5cbbc62712ab50dd40e18 upstream.

Fixes: ff1c038addc4 ("Check SMB3 dialects against downgrade attacks")
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index cd429ce777315189f44043959554bfb48062cf86..7f9cfef8ad579c79ad47cb780562e9bdd148b966 100644 (file)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -479,7 +479,7 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 {
        int rc = 0;
        struct validate_negotiate_info_req vneg_inbuf;
-       struct validate_negotiate_info_rsp *pneg_rsp;
+       struct validate_negotiate_info_rsp *pneg_rsp = NULL;
        u32 rsplen;
 
        cifs_dbg(FYI, "validate negotiate\n");
@@ -536,7 +536,7 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 
                /* relax check since Mac returns max bufsize allowed on ioctl */
                if (rsplen > CIFSMaxBufSize)
-                       return -EIO;
+                       goto err_rsp_free;
        }
 
        /* check validate negotiate info response matches what we got earlier */
@@ -555,10 +555,13 @@ int smb3_validate_negotiate(const unsigned int xid, struct cifs_tcon *tcon)
 
        /* validate negotiate successful */
        cifs_dbg(FYI, "validate negotiate info successful\n");
+       kfree(pneg_rsp);
        return 0;
 
 vneg_out:
        cifs_dbg(VFS, "protocol revalidation - security settings mismatch\n");
+err_rsp_free:
+       kfree(pneg_rsp);
        return -EIO;
 }