* [nf PATCH v3 1/2] netfilter: nf_tables: Fix entries val in rule reset audit log
2023-09-13 13:51 [nf PATCH v3 0/2] nf_tables: follow-up on audit fix, add selftest Phil Sutter
@ 2023-09-13 13:51 ` Phil Sutter
2023-09-13 19:31 ` Florian Westphal
2023-09-13 13:51 ` [nf PATCH v3 2/2] selftests: netfilter: Test nf_tables audit logging Phil Sutter
2023-09-13 20:03 ` [nf PATCH v3 0/2] nf_tables: follow-up on audit fix, add selftest Pablo Neira Ayuso
2 siblings, 1 reply; 6+ messages in thread
From: Phil Sutter @ 2023-09-13 13:51 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: netfilter-devel, Florian Westphal, audit, paul, rgb
The value in idx and the number of rules handled in that particular
__nf_tables_dump_rules() call is not identical. The former is a cursor
to pick up from if multiple netlink messages are needed, so its value is
ever increasing. Fixing this is not just a matter of subtracting s_idx
from it, though: When resetting rules in multiple chains,
__nf_tables_dump_rules() is called for each and cb->args[0] is not
adjusted in between. Introduce a dedicated counter to record the number
of rules reset in this call in a less confusing way.
While being at it, prevent the direct return upon buffer exhaustion: Any
rules previously dumped into that skb would evade audit logging
otherwise.
Fixes: 9b5ba5c9c5109 ("netfilter: nf_tables: Unbreak audit log reset")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
Changes since v2:
- Restore per-chain logging as requested.
Changes since v1:
- Use max_t() to eliminate the kernel warning
---
net/netfilter/nf_tables_api.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index e429ebba74b3d..446e1882428e6 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3449,6 +3449,8 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
struct net *net = sock_net(skb->sk);
const struct nft_rule *rule, *prule;
unsigned int s_idx = cb->args[0];
+ unsigned int entries = 0;
+ int ret = 0;
u64 handle;
prule = NULL;
@@ -3471,9 +3473,11 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
NFT_MSG_NEWRULE,
NLM_F_MULTI | NLM_F_APPEND,
table->family,
- table, chain, rule, handle, reset) < 0)
- return 1;
-
+ table, chain, rule, handle, reset) < 0) {
+ ret = 1;
+ break;
+ }
+ entries++;
nl_dump_check_consistent(cb, nlmsg_hdr(skb));
cont:
prule = rule;
@@ -3481,10 +3485,10 @@ static int __nf_tables_dump_rules(struct sk_buff *skb,
(*idx)++;
}
- if (reset && *idx)
- audit_log_rule_reset(table, cb->seq, *idx);
+ if (reset && entries)
+ audit_log_rule_reset(table, cb->seq, entries);
- return 0;
+ return ret;
}
static int nf_tables_dump_rules(struct sk_buff *skb,
--
2.41.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [nf PATCH v3 2/2] selftests: netfilter: Test nf_tables audit logging
2023-09-13 13:51 [nf PATCH v3 0/2] nf_tables: follow-up on audit fix, add selftest Phil Sutter
2023-09-13 13:51 ` [nf PATCH v3 1/2] netfilter: nf_tables: Fix entries val in rule reset audit log Phil Sutter
@ 2023-09-13 13:51 ` Phil Sutter
2023-09-13 20:03 ` [nf PATCH v3 0/2] nf_tables: follow-up on audit fix, add selftest Pablo Neira Ayuso
2 siblings, 0 replies; 6+ messages in thread
From: Phil Sutter @ 2023-09-13 13:51 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: netfilter-devel, Florian Westphal, audit, paul, rgb
Compare NETFILTER_CFG type audit logs emitted from kernel upon ruleset
modifications against expected output.
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
Changes since v1:
- Implement a custom log reader which turns audit logging on/off as
needed, drop auditd dependency.
- Record required CONFIG_AUDIT in 'config' file.
- Add SPDX license headers.
- Open readonly fd to logfile for continuous reading, shell's redirect
doesn't like file truncating to clear previous output.
- Use a single 'diff' call for status and error reporting.
- Use ruleset setup commands for audit log testing, too.
- Extend many rules reset test by two more commands.
---
tools/testing/selftests/netfilter/.gitignore | 1 +
tools/testing/selftests/netfilter/Makefile | 4 +-
.../selftests/netfilter/audit_logread.c | 165 ++++++++++++++++++
tools/testing/selftests/netfilter/config | 1 +
.../testing/selftests/netfilter/nft_audit.sh | 108 ++++++++++++
5 files changed, 277 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/netfilter/audit_logread.c
create mode 100755 tools/testing/selftests/netfilter/nft_audit.sh
diff --git a/tools/testing/selftests/netfilter/.gitignore b/tools/testing/selftests/netfilter/.gitignore
index 4cb887b574138..4b2928e1c19d8 100644
--- a/tools/testing/selftests/netfilter/.gitignore
+++ b/tools/testing/selftests/netfilter/.gitignore
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0-only
nf-queue
connect_close
+audit_logread
diff --git a/tools/testing/selftests/netfilter/Makefile b/tools/testing/selftests/netfilter/Makefile
index 3686bfa6c58d7..321db8850da00 100644
--- a/tools/testing/selftests/netfilter/Makefile
+++ b/tools/testing/selftests/netfilter/Makefile
@@ -6,13 +6,13 @@ TEST_PROGS := nft_trans_stress.sh nft_fib.sh nft_nat.sh bridge_brouter.sh \
nft_concat_range.sh nft_conntrack_helper.sh \
nft_queue.sh nft_meta.sh nf_nat_edemux.sh \
ipip-conntrack-mtu.sh conntrack_tcp_unreplied.sh \
- conntrack_vrf.sh nft_synproxy.sh rpath.sh
+ conntrack_vrf.sh nft_synproxy.sh rpath.sh nft_audit.sh
HOSTPKG_CONFIG := pkg-config
CFLAGS += $(shell $(HOSTPKG_CONFIG) --cflags libmnl 2>/dev/null)
LDLIBS += $(shell $(HOSTPKG_CONFIG) --libs libmnl 2>/dev/null || echo -lmnl)
-TEST_GEN_FILES = nf-queue connect_close
+TEST_GEN_FILES = nf-queue connect_close audit_logread
include ../lib.mk
diff --git a/tools/testing/selftests/netfilter/audit_logread.c b/tools/testing/selftests/netfilter/audit_logread.c
new file mode 100644
index 0000000000000..a0a880fc2d9de
--- /dev/null
+++ b/tools/testing/selftests/netfilter/audit_logread.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#include <linux/audit.h>
+#include <linux/netlink.h>
+
+static int fd;
+
+#define MAX_AUDIT_MESSAGE_LENGTH 8970
+struct audit_message {
+ struct nlmsghdr nlh;
+ union {
+ struct audit_status s;
+ char data[MAX_AUDIT_MESSAGE_LENGTH];
+ } u;
+};
+
+int audit_recv(int fd, struct audit_message *rep)
+{
+ struct sockaddr_nl addr;
+ socklen_t addrlen = sizeof(addr);
+ int ret;
+
+ do {
+ ret = recvfrom(fd, rep, sizeof(*rep), 0,
+ (struct sockaddr *)&addr, &addrlen);
+ } while (ret < 0 && errno == EINTR);
+
+ if (ret < 0 ||
+ addrlen != sizeof(addr) ||
+ addr.nl_pid != 0 ||
+ rep->nlh.nlmsg_type == NLMSG_ERROR) /* short-cut for now */
+ return -1;
+
+ return ret;
+}
+
+int audit_send(int fd, uint16_t type, uint32_t key, uint32_t val)
+{
+ static int seq = 0;
+ struct audit_message msg = {
+ .nlh = {
+ .nlmsg_len = NLMSG_SPACE(sizeof(msg.u.s)),
+ .nlmsg_type = type,
+ .nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK,
+ .nlmsg_seq = ++seq,
+ },
+ .u.s = {
+ .mask = key,
+ .enabled = key == AUDIT_STATUS_ENABLED ? val : 0,
+ .pid = key == AUDIT_STATUS_PID ? val : 0,
+ }
+ };
+ struct sockaddr_nl addr = {
+ .nl_family = AF_NETLINK,
+ };
+ int ret;
+
+ do {
+ ret = sendto(fd, &msg, msg.nlh.nlmsg_len, 0,
+ (struct sockaddr *)&addr, sizeof(addr));
+ } while (ret < 0 && errno == EINTR);
+
+ if (ret != (int)msg.nlh.nlmsg_len)
+ return -1;
+ return 0;
+}
+
+int audit_set(int fd, uint32_t key, uint32_t val)
+{
+ struct audit_message rep = { 0 };
+ int ret;
+
+ ret = audit_send(fd, AUDIT_SET, key, val);
+ if (ret)
+ return ret;
+
+ ret = audit_recv(fd, &rep);
+ if (ret < 0)
+ return ret;
+ return 0;
+}
+
+int readlog(int fd)
+{
+ struct audit_message rep = { 0 };
+ int ret = audit_recv(fd, &rep);
+ const char *sep = "";
+ char *k, *v;
+
+ if (ret < 0)
+ return ret;
+
+ if (rep.nlh.nlmsg_type != AUDIT_NETFILTER_CFG)
+ return 0;
+
+ /* skip the initial "audit(...): " part */
+ strtok(rep.u.data, " ");
+
+ while ((k = strtok(NULL, "="))) {
+ v = strtok(NULL, " ");
+
+ /* these vary and/or are uninteresting, ignore */
+ if (!strcmp(k, "pid") ||
+ !strcmp(k, "comm") ||
+ !strcmp(k, "subj"))
+ continue;
+
+ /* strip the varying sequence number */
+ if (!strcmp(k, "table"))
+ *strchrnul(v, ':') = '\0';
+
+ printf("%s%s=%s", sep, k, v);
+ sep = " ";
+ }
+ if (*sep) {
+ printf("\n");
+ fflush(stdout);
+ }
+ return 0;
+}
+
+void cleanup(int sig)
+{
+ audit_set(fd, AUDIT_STATUS_ENABLED, 0);
+ close(fd);
+ if (sig)
+ exit(0);
+}
+
+int main(int argc, char **argv)
+{
+ struct sigaction act = {
+ .sa_handler = cleanup,
+ };
+
+ fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_AUDIT);
+ if (fd < 0) {
+ perror("Can't open netlink socket");
+ return -1;
+ }
+
+ if (sigaction(SIGTERM, &act, NULL) < 0 ||
+ sigaction(SIGINT, &act, NULL) < 0) {
+ perror("Can't set signal handler");
+ close(fd);
+ return -1;
+ }
+
+ audit_set(fd, AUDIT_STATUS_ENABLED, 1);
+ audit_set(fd, AUDIT_STATUS_PID, getpid());
+
+ while (1)
+ readlog(fd);
+}
diff --git a/tools/testing/selftests/netfilter/config b/tools/testing/selftests/netfilter/config
index 4faf2ce021d90..7c42b1b2c69b4 100644
--- a/tools/testing/selftests/netfilter/config
+++ b/tools/testing/selftests/netfilter/config
@@ -6,3 +6,4 @@ CONFIG_NFT_REDIR=m
CONFIG_NFT_MASQ=m
CONFIG_NFT_FLOW_OFFLOAD=m
CONFIG_NF_CT_NETLINK=m
+CONFIG_AUDIT=y
diff --git a/tools/testing/selftests/netfilter/nft_audit.sh b/tools/testing/selftests/netfilter/nft_audit.sh
new file mode 100755
index 0000000000000..93e2bfc204da7
--- /dev/null
+++ b/tools/testing/selftests/netfilter/nft_audit.sh
@@ -0,0 +1,108 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Check that audit logs generated for nft commands are as expected.
+
+SKIP_RC=4
+RC=0
+
+nft --version >/dev/null 2>&1 || {
+ echo "SKIP: missing nft tool"
+ exit $SKIP_RC
+}
+
+logfile=$(mktemp)
+echo "logging into $logfile"
+./audit_logread >"$logfile" &
+logread_pid=$!
+trap 'kill $logread_pid; rm -f $logfile' EXIT
+exec 3<"$logfile"
+
+do_test() { # (cmd, log)
+ echo -n "testing for cmd: $1 ... "
+ cat <&3 >/dev/null
+ $1 >/dev/null || exit 1
+ sleep 0.1
+ res=$(diff -a -u <(echo "$2") - <&3)
+ [ $? -eq 0 ] && { echo "OK"; return; }
+ echo "FAIL"
+ echo "$res"
+ ((RC++))
+}
+
+nft flush ruleset
+
+for table in t1 t2; do
+ do_test "nft add table $table" \
+ "table=$table family=2 entries=1 op=nft_register_table"
+
+ do_test "nft add chain $table c1" \
+ "table=$table family=2 entries=1 op=nft_register_chain"
+
+ do_test "nft add chain $table c2; add chain $table c3" \
+ "table=$table family=2 entries=2 op=nft_register_chain"
+
+ cmd="add rule $table c1 counter"
+
+ do_test "nft $cmd" \
+ "table=$table family=2 entries=1 op=nft_register_rule"
+
+ do_test "nft $cmd; $cmd" \
+ "table=$table family=2 entries=2 op=nft_register_rule"
+
+ cmd=""
+ sep=""
+ for chain in c2 c3; do
+ for i in {1..3}; do
+ cmd+="$sep add rule $table $chain counter"
+ sep=";"
+ done
+ done
+ do_test "nft $cmd" \
+ "table=$table family=2 entries=6 op=nft_register_rule"
+done
+
+do_test 'nft reset rules t1 c2' \
+'table=t1 family=2 entries=3 op=nft_reset_rule'
+
+do_test 'nft reset rules table t1' \
+'table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule'
+
+do_test 'nft reset rules' \
+'table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule'
+
+for ((i = 0; i < 500; i++)); do
+ echo "add rule t2 c3 counter accept comment \"rule $i\""
+done | do_test 'nft -f -' \
+'table=t2 family=2 entries=500 op=nft_register_rule'
+
+do_test 'nft reset rules t2 c3' \
+'table=t2 family=2 entries=189 op=nft_reset_rule
+table=t2 family=2 entries=188 op=nft_reset_rule
+table=t2 family=2 entries=126 op=nft_reset_rule'
+
+do_test 'nft reset rules t2' \
+'table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=186 op=nft_reset_rule
+table=t2 family=2 entries=188 op=nft_reset_rule
+table=t2 family=2 entries=129 op=nft_reset_rule'
+
+do_test 'nft reset rules' \
+'table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t1 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=3 op=nft_reset_rule
+table=t2 family=2 entries=180 op=nft_reset_rule
+table=t2 family=2 entries=188 op=nft_reset_rule
+table=t2 family=2 entries=135 op=nft_reset_rule'
+
+exit $RC
--
2.41.0
^ permalink raw reply related [flat|nested] 6+ messages in thread