35 lines
1.4 KiB
Diff
35 lines
1.4 KiB
Diff
From 92124e84be68005be92cce046c7c679b98199d66 Mon Sep 17 00:00:00 2001
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From: Jacek Migacz <jmigacz@redhat.com>
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Date: Mon, 26 Feb 2024 13:56:36 +0100
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Subject: [PATCH] resolved: reduce the maximum nsec3 iterations to 100
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According to RFC9267, the 2500 value is not helpful, and in fact it can
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be harmful to permit a large number of iterations. Combined with limits
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on the number of signature validations, I expect this will mitigate the
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impact of maliciously crafted domains designed to cause excessive
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cryptographic work.
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(cherry picked from commit eba291124bc11f03732d1fc468db3bfac069f9cb)
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Related: RHEL-26644
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---
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src/resolve/resolved-dns-dnssec.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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diff --git a/src/resolve/resolved-dns-dnssec.c b/src/resolve/resolved-dns-dnssec.c
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index 5dbfbc94c7..5a0540568c 100644
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--- a/src/resolve/resolved-dns-dnssec.c
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+++ b/src/resolve/resolved-dns-dnssec.c
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@@ -22,8 +22,9 @@
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/* Permit a maximum clock skew of 1h 10min. This should be enough to deal with DST confusion */
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#define SKEW_MAX (1*USEC_PER_HOUR + 10*USEC_PER_MINUTE)
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-/* Maximum number of NSEC3 iterations we'll do. RFC5155 says 2500 shall be the maximum useful value */
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-#define NSEC3_ITERATIONS_MAX 2500
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+/* Maximum number of NSEC3 iterations we'll do. RFC5155 says 2500 shall be the maximum useful value, but
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+ * RFC9276 § 3.2 says that we should reduce the acceptable iteration count */
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+#define NSEC3_ITERATIONS_MAX 100
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/*
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* The DNSSEC Chain of trust:
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