ptrace: use fsuid, fsgid, effective creds for fs access checks

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / security / commoncap.c

diff --git a/security/commoncap.c b/security/commoncap.c
index c9219a66b7c6d99e557b4d8f36755842e2332e37..4fd7bf2b19e1d769bea8e5c7518eba22418ac016 100644 (file)
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -142,12 +142,17 @@ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode)
 {
        int ret = 0;
        const struct cred *cred, *child_cred;
+       const kernel_cap_t *caller_caps;
 
        rcu_read_lock();
        cred = current_cred();
        child_cred = __task_cred(child);
+       if (mode & PTRACE_MODE_FSCREDS)
+               caller_caps = &cred->cap_effective;
+       else
+               caller_caps = &cred->cap_permitted;
        if (cred->user_ns == child_cred->user_ns &&
-           cap_issubset(child_cred->cap_permitted, cred->cap_permitted))
+           cap_issubset(child_cred->cap_permitted, *caller_caps))
                goto out;
        if (ns_capable(child_cred->user_ns, CAP_SYS_PTRACE))
                goto out;