Make the comments a little more clear about PRIV_KMEM_*, explicitly

referring to /dev/[k]mem and noting it's about opening the files rather
than actually reading and writing.

Reviewed by:	jmallett

2 files changed, 6 insertions, 5 deletions

diff --git a/sys/kern/kern_priv.c b/sys/kern/kern_priv.c
index 204e00b..4d266ab 100644
--- a/sys/kern/kern_priv.c
+++ b/sys/kern/kern_priv.c
@@ -142,8 +142,9 @@ priv_check_cred(struct ucred *cred, int priv, int flags)
 	}
 
 	/*
-	 * Writes to kernel memory are a typical root-only operation,
-	 * but non-root users are expected to be able to read it.
+	 * Writes to kernel/physical memory are a typical root-only operation,
+	 * but non-root users are expected to be able to read it (provided they
+	 * have permission to access /dev/[k]mem).
 	 */
 	if (priv == PRIV_KMEM_READ) {
 		error = 0;
diff --git a/sys/sys/priv.h b/sys/sys/priv.h
index 5104a10..3fedccd 100644
--- a/sys/sys/priv.h
+++ b/sys/sys/priv.h
@@ -494,10 +494,10 @@
 #define	PRIV_RCTL_REMOVE_RULE	674
 
 /*
- * Kernel memory privileges.
+ * mem(4) privileges.
  */
-#define	PRIV_KMEM_READ		680	/* Read from kernel memory. */
-#define	PRIV_KMEM_WRITE		681	/* Write to kernel memory. */
+#define	PRIV_KMEM_READ		680	/* Open mem/kmem for reading. */
+#define	PRIV_KMEM_WRITE		681	/* Open mem/kmem for writing. */
 
 /*
  * Track end of privilege list.