Introduce the new function

        p_trespass(struct proc *p1, struct proc *p2)
which returns zero or an errno depending on the legality of p1 trespassing
on p2.

Replace kern_sig.c:CANSIGNAL() with call to p_trespass() and one
extra signal related check.

Replace procfs.h:CHECKIO() macros with calls to p_trespass().

Only show command lines to process which can trespass on the target
process.

1 files changed, 25 insertions, 0 deletions

diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c
index 63d4346..1611cc3 100644
--- a/sys/kern/kern_prot.c
+++ b/sys/kern/kern_prot.c
@@ -793,6 +793,31 @@ suser_xxx(cred, proc, flag)
 }
 
 /*
+ * Return zero if p1 can fondle p2, return errno (EPERM/ESRCH) otherwise.
+ */
+
+int
+p_trespass(struct proc *p1, struct proc *p2)
+{
+
+	if (p1 == p2)
+		return (0);
+	if (!PRISON_CHECK(p1, p2))
+		return (ESRCH);
+	if (p1->p_cred->p_ruid == p2->p_cred->p_ruid)
+		return (0);
+	if (p1->p_ucred->cr_uid == p2->p_cred->p_ruid)
+		return (0);
+	if (p1->p_cred->p_ruid == p2->p_ucred->cr_uid)
+		return (0);
+	if (p1->p_ucred->cr_uid == p2->p_ucred->cr_uid)
+		return (0);
+	if (!suser_xxx(0, p1, PRISON_ROOT))
+		return (0);
+	return (EPERM);
+}
+
+/*
  * Allocate a zeroed cred structure.
  */
 struct ucred *