Module Name: src
Committed By: martin
Date: Tue Aug 1 16:10:59 UTC 2023
Modified Files:
src/sys/kern [netbsd-10]: kern_entropy.c
Log Message:
Pull up following revision(s) (requested by riastradh in ticket #294):
sys/kern/kern_entropy.c: revision 1.60
sys/kern/kern_entropy.c: revision 1.61
entropy(9): On flags change, cancel any scheduled consolidation.
We've been instructed to lose confidence in existing entropy sources,
so let's make sure to re-gather enough entropy before the next
consolidation can happen, in case some of what would be counted in
consolidation is from those entropy sources.
entropy(9): Avoid race between rnd_add_data and ioctl(RNDCTL).
To generate a diff of this commit:
cvs rdiff -u -r1.57.4.2 -r1.57.4.3 src/sys/kern/kern_entropy.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_entropy.c
diff -u src/sys/kern/kern_entropy.c:1.57.4.2 src/sys/kern/kern_entropy.c:1.57.4.3
--- src/sys/kern/kern_entropy.c:1.57.4.2 Mon Jul 31 15:57:43 2023
+++ src/sys/kern/kern_entropy.c Tue Aug 1 16:10:59 2023
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_entropy.c,v 1.57.4.2 2023/07/31 15:57:43 martin Exp $ */
+/* $NetBSD: kern_entropy.c,v 1.57.4.3 2023/08/01 16:10:59 martin Exp $ */
/*-
* Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -75,7 +75,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_entropy.c,v 1.57.4.2 2023/07/31 15:57:43 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_entropy.c,v 1.57.4.3 2023/08/01 16:10:59 martin Exp $");
#include <sys/param.h>
#include <sys/types.h>
@@ -1910,6 +1910,14 @@ rnd_add_data(struct krndsource *rs, cons
return;
}
+ /*
+ * Hold up the reset xcall before it zeroes the entropy counts
+ * on this CPU or globally. Otherwise, we might leave some
+ * nonzero entropy attributed to an untrusted source in the
+ * event of a race with a change to flags.
+ */
+ kpreempt_disable();
+
/* Load a snapshot of the flags. Ioctl may change them under us. */
flags = atomic_load_relaxed(&rs->flags);
@@ -1922,7 +1930,7 @@ rnd_add_data(struct krndsource *rs, cons
if (!atomic_load_relaxed(&entropy_collection) ||
ISSET(flags, RND_FLAG_NO_COLLECT) ||
!ISSET(flags, RND_FLAG_COLLECT_VALUE|RND_FLAG_COLLECT_TIME))
- return;
+ goto out;
/* If asked, ignore the estimate. */
if (ISSET(flags, RND_FLAG_NO_ESTIMATE))
@@ -1939,6 +1947,9 @@ rnd_add_data(struct krndsource *rs, cons
rnd_add_data_1(rs, &extra, sizeof extra, 0,
RND_FLAG_COLLECT_TIME);
}
+
+out: /* Allow concurrent changes to flags to finish. */
+ kpreempt_enable();
}
static unsigned
@@ -2414,6 +2425,7 @@ entropy_ioctl(unsigned long cmd, void *d
E->pending = 0;
atomic_store_relaxed(&E->needed,
ENTROPY_CAPACITY*NBBY);
+ E->consolidate = false;
mutex_exit(&E->lock);
}
