47 lines
1.7 KiB
Diff
47 lines
1.7 KiB
Diff
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From 1dcbf8ed6849543fcaffb8af0d50e08e27232ce2 Mon Sep 17 00:00:00 2001
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From: Phil Sutter <phil@nwl.cc>
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Date: Fri, 21 Jul 2023 13:14:36 +0200
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Subject: [PATCH] nft: Special casing for among match in compare_matches()
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When other extensions may have "garbage" appended to their data which
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should not be considered for match comparison, among match is the
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opposite in that it extends its data beyond the value in 'size' field.
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Add special casing to cover for this, avoiding false-positive rule
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comparison.
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Fixes: 26753888720d8 ("nft: bridge: Rudimental among extension support")
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Signed-off-by: Phil Sutter <phil@nwl.cc>
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(cherry picked from commit 10583537004f7ecd4aa11f6c12b7ba73fb77fc11)
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---
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iptables/nft-shared.c | 7 +++++--
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1 file changed, 5 insertions(+), 2 deletions(-)
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diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c
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index ed093c07d7617..0b5745f7e82f4 100644
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--- a/iptables/nft-shared.c
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+++ b/iptables/nft-shared.c
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@@ -911,6 +911,7 @@ bool compare_matches(struct xtables_rule_match *mt1,
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for (mp1 = mt1, mp2 = mt2; mp1 && mp2; mp1 = mp1->next, mp2 = mp2->next) {
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struct xt_entry_match *m1 = mp1->match->m;
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struct xt_entry_match *m2 = mp2->match->m;
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+ size_t cmplen = mp1->match->userspacesize;
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if (strcmp(m1->u.user.name, m2->u.user.name) != 0) {
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DEBUGP("mismatching match name\n");
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@@ -922,8 +923,10 @@ bool compare_matches(struct xtables_rule_match *mt1,
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return false;
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}
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- if (memcmp(m1->data, m2->data,
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- mp1->match->userspacesize) != 0) {
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+ if (!strcmp(m1->u.user.name, "among"))
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+ cmplen = m1->u.match_size - sizeof(*m1);
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+
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+ if (memcmp(m1->data, m2->data, cmplen) != 0) {
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DEBUGP("mismatch match data\n");
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return false;
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}
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--
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2.40.0
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