From mboxrd@z Thu Jan 1 00:00:00 1970 From: casey.schaufler@intel.com (Casey Schaufler) Date: Thu, 27 Sep 2018 12:17:20 -0700 Subject: [PATCH 6/5] capability: Repair sidechannel test in ptrace In-Reply-To: <20180824224117.3356-1-casey.schaufler@intel.com> References: <20180824224117.3356-1-casey.schaufler@intel.com> Message-ID: <20180927191720.9480-1-casey.schaufler@intel.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org From: Casey Schaufler The PTRACE_MODE_SCHED check erroniously returns 0 in all cases. It should be returning -EPERM. This fixes the logic to correct that error. Signed-off-by: Casey Schaufler --- security/commoncap.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/security/commoncap.c b/security/commoncap.c index e77457110d05..70a7e3d19c16 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -152,9 +152,8 @@ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) if (cred->user_ns == child_cred->user_ns && cap_issubset(child_cred->cap_permitted, *caller_caps)) goto out; - if (mode & PTRACE_MODE_SCHED) - goto out; - if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE)) + if (!(mode & PTRACE_MODE_SCHED) && + ns_capable(child_cred->user_ns, CAP_SYS_PTRACE)) goto out; ret = -EPERM; out: -- 2.17.1