lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 16 Jan 2020 11:44:00 -0500 From: Sasha Levin <sashal@...nel.org> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org Cc: Jann Horn <jannh@...gle.com>, John Johansen <john.johansen@...onical.com>, Sasha Levin <sashal@...nel.org>, linux-security-module@...r.kernel.org Subject: [PATCH AUTOSEL 4.19 009/671] apparmor: don't try to replace stale label in ptrace access check From: Jann Horn <jannh@...gle.com> [ Upstream commit 1f8266ff58840d698a1e96d2274189de1bdf7969 ] As a comment above begin_current_label_crit_section() explains, begin_current_label_crit_section() must run in sleepable context because when label_is_stale() is true, aa_replace_current_label() runs, which uses prepare_creds(), which can sleep. Until now, the ptrace access check (which runs with a task lock held) violated this rule. Also add a might_sleep() assertion to begin_current_label_crit_section(), because asserts are less likely to be ignored than comments. Fixes: b2d09ae449ced ("apparmor: move ptrace checks to using labels") Signed-off-by: Jann Horn <jannh@...gle.com> Signed-off-by: John Johansen <john.johansen@...onical.com> Signed-off-by: Sasha Levin <sashal@...nel.org> --- security/apparmor/include/cred.h | 2 ++ security/apparmor/lsm.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/security/apparmor/include/cred.h b/security/apparmor/include/cred.h index e287b7d0d4be..265ae6641a06 100644 --- a/security/apparmor/include/cred.h +++ b/security/apparmor/include/cred.h @@ -151,6 +151,8 @@ static inline struct aa_label *begin_current_label_crit_section(void) { struct aa_label *label = aa_current_raw_label(); + might_sleep(); + if (label_is_stale(label)) { label = aa_get_newest_label(label); if (aa_replace_current_label(label) == 0) diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 8b8b70620bbe..e3f40c20b9b4 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -114,13 +114,13 @@ static int apparmor_ptrace_access_check(struct task_struct *child, struct aa_label *tracer, *tracee; int error; - tracer = begin_current_label_crit_section(); + tracer = __begin_current_label_crit_section(); tracee = aa_get_task_label(child); error = aa_may_ptrace(tracer, tracee, (mode & PTRACE_MODE_READ) ? AA_PTRACE_READ : AA_PTRACE_TRACE); aa_put_label(tracee); - end_current_label_crit_section(tracer); + __end_current_label_crit_section(tracer); return error; } -- 2.20.1
Powered by blists - more mailing lists