libpcap: Fix CVE-2026-18313

NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-18313
Upstream-commit: https://github.com/the-tcpdump-group/libpcap/commit/f9775af1a0ec76db60c7213241e6b48f1be10ac7

(From OE-Core rev: 6cdcaaf4c347a32d5408653f8eb343c8e4fb04ff)

Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Paul Barker <paul@pbarker.dev>

meta/recipes-connectivity/libpcap/libpcap/06-CVE-2026-18313.patch

@@ -0,0 +1,84 @@
+From f9775af1a0ec76db60c7213241e6b48f1be10ac7 Mon Sep 17 00:00:00 2001
+From: Denis Ovsienko <denis@ovsienko.info>
+Date: Sat, 1 Aug 2026 18:24:48 +0100
+Subject: [PATCH] CVE-2026-18313: Fix a memory leak in rpcapd.
+
+This vulnerability was originally reported publicly, hence no credit is
+given.
+
+daemon_unpackapplyfilter() can allocate a temporary buffer for up to
+RPCAP_BPF_MAXINSNS (8192) BPF instructions (65536 bytes) per each
+received RPCAP_MSG_UPDATEFILTER_REQ or RPCAP_MSG_STARTCAP_REQ message.
+It never frees the memory, so repeated messages from a client will
+eventually leak enough memory on the server to cause problems.  This
+holds for all connections that pass the validation and some connections
+that do not.
+
+48 bytes in 1 blocks are definitely lost in loss record 2 of 2
+   at 0x4844818: malloc (vg_replace_malloc.c:446)
+   by 0x111AAB: daemon_unpackapplyfilter (daemon.c:2372)
+   by 0x113279: daemon_msg_startcap_req.constprop.0 (daemon.c:2139)
+   by 0x114808: daemon_serviceloop (daemon.c:901)
+   by 0x115BC7: accept_connection (rpcapd.c:1321)
+   by 0x115BC7: accept_connections (rpcapd.c:1118)
+   by 0x115BC7: main_startup (rpcapd.c:709)
+   by 0x1112BD: main (rpcapd.c:567)
+
+To fix this, after a successful malloc() return exactly once, after the
+free() call.
+
+(backported from commit 26a1c75702b105ac8788014f35f1b5c57fa6043b)
+
+(cherry picked from commit f9775af1a0ec76db60c7213241e6b48f1be10ac7)
+
+Notes on backporting to 1.10.4:
+ - The upstream CHANGES/changelog hunk is not backported.
+
+Upstream-Status: Backport [https://github.com/the-tcpdump-group/libpcap/commit/f9775af1a0ec76db60c7213241e6b48f1be10ac7]
+CVE: CVE-2026-18313
+Signed-off-by: Jaipaul Cheernam <jaipaul.cheernam@est.tech>
+---
+diff --git a/rpcapd/daemon.c b/rpcapd/daemon.c
+index 9b0f8285..b0268688 100644
+--- a/rpcapd/daemon.c
++++ b/rpcapd/daemon.c
+@@ -2378,14 +2378,8 @@ daemon_unpackapplyfilter(SOCKET sockctrl, SSL *ctrl_ssl, struct session *session
+ 	{
+ 		status = rpcapd_recv(sockctrl, ctrl_ssl, (char *) &insn,
+ 		    sizeof(struct rpcap_filterbpf_insn), plenp, errmsgbuf);
+-		if (status == -1)
+-		{
+-			return -1;
+-		}
+-		if (status == -2)
+-		{
+-			return -2;
+-		}
++		if (status == -1 || status == -2)
++			goto free_and_return_status;
+ 
+ 		bf_insn->code = ntohs(insn.code);
+ 		bf_insn->jf = insn.jf;
+@@ -2401,16 +2395,19 @@ daemon_unpackapplyfilter(SOCKET sockctrl, SSL *ctrl_ssl, struct session *session
+ 	if (bpf_validate(bf_prog.bf_insns, bf_prog.bf_len) == 0)
+ 	{
+ 		snprintf(errmsgbuf, PCAP_ERRBUF_SIZE, "The filter contains bogus instructions");
+-		return -2;
++		status = -2;
++		goto free_and_return_status;
+ 	}
+ 
+ 	if (pcap_setfilter(session->fp, &bf_prog))
+ 	{
+ 		snprintf(errmsgbuf, PCAP_ERRBUF_SIZE, "RPCAP error: %s", pcap_geterr(session->fp));
+-		return -2;
++		status = -2;
+ 	}
+ 
+-	return 0;
++free_and_return_status:
++	free(bf_prog.bf_insns);
++	return status;
+ }
+ 
+ static int

meta/recipes-connectivity/libpcap/libpcap_1.10.4.bb

@@ -22,6 +22,7 @@ SRC_URI = "https://www.tcpdump.org/release/${BP}.tar.gz \
            file://03-CVE-2026-31911.patch \
            file://04-CVE-2026-6244.patch \
            file://05-CVE-2026-6554.patch \
+           file://06-CVE-2026-18313.patch \
           "
 
 SRC_URI[sha256sum] = "ed19a0383fad72e3ad435fd239d7cd80d64916b87269550159d20e47160ebe5f"