From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5023419F470; Thu, 15 Aug 2024 13:57:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723730228; cv=none; b=blTHb1WclsjeOo95+5n8yW4SzWz6FWYaQ/Id3JtKwZyksw40GLAE248y/NgGXeAoBxWHr05OBQJFnuGDmm6e56cC+JmYEArMDCfU4rDofARC+PBUlr8VtcencJ23ECg0mK0k5d/VLhCW4DYfxeI0HvG7aXd3nnWEfaDJbctN5sc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723730228; c=relaxed/simple; bh=EeglIGJJta+nA9c3vmml8ules9kKrs4TMVZIoMuXvTQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=k1E7p0gv09QA23TQ4OKEw5gEmu+nbijbWqjumy6ill/TWmGHGxiqqdfsvnMhWQJraJRXnhEVW/VrD9kO4j/g85jTGGYAf+dqojzWo8+H0+hG0ViAjFKD0bNT9hZi5Wwda+zGhWOzE9v9NxZuNswDViLhHJShHyXy/ajx/UbuRoU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rGZt04aV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rGZt04aV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE1EFC32786; Thu, 15 Aug 2024 13:57:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723730228; bh=EeglIGJJta+nA9c3vmml8ules9kKrs4TMVZIoMuXvTQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rGZt04aVFYRiYwANJtSQ1mY8i99j06qNQWGHRoCn3bE4kGs0+AxrqlwjHM+t3CRGA tKxdaoRHxUEv9edMiyEoH/Fbn+R2YkBd1p2D6/rYIL+ETrvBz197/k6Q2Ik05et1ln 4hJLqKHvehDhsjT77vjj4yDlYvWiwWu03BcmIvZc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Al Viro Subject: [PATCH 5.15 344/484] protect the fetch of ->fd[fd] in do_dup2() from mispredictions Date: Thu, 15 Aug 2024 15:23:22 +0200 Message-ID: <20240815131954.707901929@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240815131941.255804951@linuxfoundation.org> References: <20240815131941.255804951@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 8aa37bde1a7b645816cda8b80df4753ecf172bf1 upstream. both callers have verified that fd is not greater than ->max_fds; however, misprediction might end up with tofree = fdt->fd[fd]; being speculatively executed. That's wrong for the same reasons why it's wrong in close_fd()/file_close_fd_locked(); the same solution applies - array_index_nospec(fd, fdt->max_fds) could differ from fd only in case of speculative execution on mispredicted path. Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/file.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/file.c +++ b/fs/file.c @@ -1148,6 +1148,7 @@ __releases(&files->file_lock) * tables and this condition does not arise without those. */ fdt = files_fdtable(files); + fd = array_index_nospec(fd, fdt->max_fds); tofree = fdt->fd[fd]; if (!tofree && fd_is_open(fd, fdt)) goto Ebusy;