From patchwork Wed Jul 11 20:05:01 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [1/1, ONEIRIC, PRECISE, CVE-2012-3375] epoll: clear the tfile_check_list on -ELOOP Date: Wed, 11 Jul 2012 10:05:01 -0000 From: Brad Figg X-Patchwork-Id: 170508 Message-Id: <1342037101-25923-2-git-send-email-brad.figg@canonical.com> To: kernel-team@lists.ubuntu.com From: Jason Baron CVE-2012-3375 BugLink: http://bugs.launchpad.net/bugs/1021811 An epoll_ctl(,EPOLL_CTL_ADD,,) operation can return '-ELOOP' to prevent circular epoll dependencies from being created. However, in that case we do not properly clear the 'tfile_check_list'. Thus, add a call to clear_tfile_check_list() for the -ELOOP case. Signed-off-by: Jason Baron Reported-by: Yurij M. Plotnikov Cc: Nelson Elhage Cc: Davide Libenzi Tested-by: Alexandra N. Kossovsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds (cherry picked from commit 13d518074a952d33d47c428419693f63389547e9) Signed-off-by: Brad Figg --- fs/eventpoll.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 4d9d3a4..a6f3763 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1629,8 +1629,10 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, if (op == EPOLL_CTL_ADD) { if (is_file_epoll(tfile)) { error = -ELOOP; - if (ep_loop_check(ep, tfile) != 0) + if (ep_loop_check(ep, tfile) != 0) { + clear_tfile_check_list(); goto error_tgt_fput; + } } else list_add(&tfile->f_tfile_llink, &tfile_check_list); }