[wrynose][PATCH 4/7] libpcap: Fix CVE-2026-6244

[Jaipaul Cheernam <jaipaul.cheernam@est.tech>]

NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-6244
Upstream-commit: https://github.com/the-tcpdump-group/libpcap/commit/98bb921b141aa642faedbf2ac510541c76499a19
Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
---
 .../libpcap/libpcap/04-CVE-2026-6244.patch    | 62 +++++++++++++++++++
 .../libpcap/libpcap_1.10.6.bb                 |  1 +
 2 files changed, 63 insertions(+)
 create mode 100644 meta/recipes-connectivity/libpcap/libpcap/04-CVE-2026-6244.patch

diff --git a/meta/recipes-connectivity/libpcap/libpcap/04-CVE-2026-6244.patch b/meta/recipes-connectivity/libpcap/libpcap/04-CVE-2026-6244.patch
new file mode 100644
index 0000000000..0ef98e4580
--- /dev/null
+++ b/meta/recipes-connectivity/libpcap/libpcap/04-CVE-2026-6244.patch
@@ -0,0 +1,62 @@
+From e2f4d78f71237c44f730fee11fa0497b756e9d81 Mon Sep 17 00:00:00 2001
+From: Denis Ovsienko <denis@ovsienko.info>
+Date: Thu, 30 Jul 2026 13:34:21 +0100
+Subject: [PATCH] CVE-2026-6244: Avoid division by zero via
+ pcap_offline_filter().
+
+The current revision of pcapint_filter_with_aux_data() for "div x" and
+"mod x" correctly rejects the packet if X is zero, but for "div #k" and
+"mod #k" it assumes that k is never zero.  This holds for programs that
+have been generated or validated by libpcap.
+
+However, this does not necessarily hold for programs that come from an
+external source via pcap_offline_filter() or [deprecated] bpf_filter()
+and have not been explicitly validated.  If the interpreter executes
+such a program, it can attempt a division by zero, which will typically
+terminate the process via SIGFPE.
+
+To fix this problem, in pcapint_filter_with_aux_data() treat "div #k"
+and "mod #k" the same way as "div x" and "mod x".
+
+(backported from commit 0b2b1ad4a1796513613ff68e9dc09049cc8e0af4)
+
+(cherry picked from commit 98bb921b141aa642faedbf2ac510541c76499a19)
+
+Upstream-Status: Backport [https://github.com/the-tcpdump-group/libpcap/commit/98bb921b141aa642faedbf2ac510541c76499a19]
+CVE: CVE-2026-6244
+Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
+---
+ CHANGES                  | 1 +
+ bpf_filter.c | 4 ++++
+ 2 files changed, 5 insertions(+)
+diff --git a/CHANGES b/CHANGES
+index f0b5974..35121e7 100644
+--- a/CHANGES
++++ b/CHANGES
+@@ -3,6 +3,7 @@
+     CVE-2026-0799: Access M[] safely in the BPF interpreter.
+     CVE-2026-31912: Mind the program bounds in pcap_offline_filter().
+     CVE-2026-31911: Fail opcodes safely in the BPF interpreter.
++    CVE-2026-6244: Avoid division by zero via pcap_offline_filter().
+ 
+ Tuesday, December 30, 2025 / The Tcpdump Group
+   Summary for 1.10.6 libpcap release
+diff --git a/bpf_filter.c b/bpf_filter.c
+index f8b842d6..0178aae5 100644
+--- a/bpf_filter.c
++++ b/bpf_filter.c
+@@ -420,10 +420,14 @@ DIAG_ON_DEFAULT_ONLY_SWITCH
+ 			continue;
+ 
+ 		case BPF_ALU|BPF_DIV|BPF_K:
++			if (pc->k == 0)
++				return 0;
+ 			A /= pc->k;
+ 			continue;
+ 
+ 		case BPF_ALU|BPF_MOD|BPF_K:
++			if (pc->k == 0)
++				return 0;
+ 			A %= pc->k;
+ 			continue;
+ 
diff --git a/meta/recipes-connectivity/libpcap/libpcap_1.10.6.bb b/meta/recipes-connectivity/libpcap/libpcap_1.10.6.bb
index da218bd87b..258a15f5ba 100644
--- a/meta/recipes-connectivity/libpcap/libpcap_1.10.6.bb
+++ b/meta/recipes-connectivity/libpcap/libpcap_1.10.6.bb
@@ -15,6 +15,7 @@ SRC_URI = "https://www.tcpdump.org/release/${BP}.tar.xz \
 	   file://01-CVE-2026-0799.patch \
 	   file://02-CVE-2026-31912.patch \
 	   file://03-CVE-2026-31911.patch \
+	   file://04-CVE-2026-6244.patch \
           "
 SRC_URI[sha256sum] = "ec97d1206bdd19cb6bdd043eaa9f0037aa732262ec68e070fd7c7b5f834d5dfc"