integ/base/dhcp/debian/patches/CVE-2022-2928.patch

From 8f1212b200fd44f9fc0ff8e35b1f2f98cc9d91b6 Mon Sep 17 00:00:00 2001
From: Zhixiong Chi <zhixiong.chi@windriver.com>
Date: Tue, 22 Nov 2022 03:55:10 -0800
Subject: [PATCH] CVE-2022-2928

Description: An option refcount overflow exists in dhcpd
Origin: upstream
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2022-2928
Forwarded: not-needed
Last-Update: 2022-10-04

The upstream patch is only in diff format without a git header which I
have created here.
[Backport patch from https://sources.debian.org/src/isc-dhcp/4.4.1-2.3%252Bdeb11u1/debian/patches/CVE-2022-2928.patch]
Signed-off-by: Zhixiong Chi <zhixiong.chi@windriver.com>
---
 common/options.c               |  7 +++++
 common/tests/option_unittest.c | 54 ++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/common/options.c b/common/options.c
index fc0e088..253cbc1 100644
--- a/common/options.c
+++ b/common/options.c
@@ -4366,6 +4366,8 @@ add_option(struct option_state *options,
 	if (!option_cache_allocate(&oc, MDL)) {
 		log_error("No memory for option cache adding %s (option %d).",
 			  option->name, option_num);
+		/* Get rid of reference created during hash lookup. */
+		option_dereference(&option, MDL);
 		return 0;
 	}
 
@@ -4377,6 +4379,8 @@ add_option(struct option_state *options,
 			     MDL)) {
 		log_error("No memory for constant data adding %s (option %d).",
 			  option->name, option_num);
+		/* Get rid of reference created during hash lookup. */
+		option_dereference(&option, MDL);
 		option_cache_dereference(&oc, MDL);
 		return 0;
 	}
@@ -4385,6 +4389,9 @@ add_option(struct option_state *options,
 	save_option(&dhcp_universe, options, oc);
 	option_cache_dereference(&oc, MDL);
 
+	/* Get rid of reference created during hash lookup. */
+	option_dereference(&option, MDL);
+
 	return 1;
 }
 
diff --git a/common/tests/option_unittest.c b/common/tests/option_unittest.c
index cd52cfb..690704d 100644
--- a/common/tests/option_unittest.c
+++ b/common/tests/option_unittest.c
@@ -130,6 +130,59 @@ ATF_TC_BODY(pretty_print_option, tc)
 }
 
 
+ATF_TC(add_option_ref_cnt);
+
+ATF_TC_HEAD(add_option_ref_cnt, tc)
+{
+    atf_tc_set_md_var(tc, "descr",
+        "Verify add_option() does not leak option ref counts.");
+}
+
+ATF_TC_BODY(add_option_ref_cnt, tc)
+{
+    struct option_state *options = NULL;
+    struct option *option = NULL;
+    unsigned int cid_code = DHO_DHCP_CLIENT_IDENTIFIER;
+    char *cid_str = "1234";
+    int refcnt_before = 0;
+
+    // Look up the option we're going to add.
+    initialize_common_option_spaces();
+    if (!option_code_hash_lookup(&option, dhcp_universe.code_hash,
+                                 &cid_code, 0, MDL)) {
+        atf_tc_fail("cannot find option definition?");
+    }
+
+    // Get the option's reference count before we call add_options.
+    refcnt_before = option->refcnt;
+
+    // Allocate a option_state to which to add an option.
+    if (!option_state_allocate(&options, MDL)) {
+	    atf_tc_fail("cannot allocat options state");
+    }
+
+    // Call add_option() to add the option to the option state.
+    if (!add_option(options, cid_code, cid_str, strlen(cid_str))) {
+	    atf_tc_fail("add_option returned 0");
+    }
+
+    // Verify that calling add_option() only adds 1 to the option ref count.
+    if (option->refcnt != (refcnt_before + 1)) {
+        atf_tc_fail("after add_option(), count is wrong, before %d, after: %d",
+                    refcnt_before, option->refcnt);
+    }
+
+    // Derefrence the option_state, this should reduce the ref count to
+    // it's starting value.
+    option_state_dereference(&options, MDL);
+
+    // Verify that dereferencing option_state restores option ref count.
+    if (option->refcnt != refcnt_before) {
+        atf_tc_fail("after state deref, count is wrong, before %d, after: %d",
+                    refcnt_before, option->refcnt);
+    }
+}
+
 /* This macro defines main() method that will call specified
    test cases. tp and simple_test_case names can be whatever you want
    as long as it is a valid variable identifier. */
@@ -137,6 +190,7 @@ ATF_TP_ADD_TCS(tp)
 {
     ATF_TP_ADD_TC(tp, option_refcnt);
     ATF_TP_ADD_TC(tp, pretty_print_option);
+    ATF_TP_ADD_TC(tp, add_option_ref_cnt);
 
     return (atf_no_error());
 }
-- 
2.34.1