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authorDaniel Borkmann <daniel@iogearbox.net>2019-11-20 22:38:16 +0100
committerAlexei Starovoitov <ast@kernel.org>2019-11-20 13:44:51 -0800
commit91e6015b082b08a74e5d9d326f651e5890a93519 (patch)
treedca309a8e414d6a13bb1a6a0a64847b5e28c50ed /kernel
parentb2e2f0e6a6f910c906c083584b6e0afd12266f22 (diff)
downloadlinux-91e6015b082b08a74e5d9d326f651e5890a93519.tar.bz2
bpf: Emit audit messages upon successful prog load and unload
Allow for audit messages to be emitted upon BPF program load and unload for having a timeline of events. The load itself is in syscall context, so additional info about the process initiating the BPF prog creation can be logged and later directly correlated to the unload event. The only info really needed from BPF side is the globally unique prog ID where then audit user space tooling can query / dump all info needed about the specific BPF program right upon load event and enrich the record, thus these changes needed here can be kept small and non-intrusive to the core. Raw example output: # auditctl -D # auditctl -a always,exit -F arch=x86_64 -S bpf # ausearch --start recent -m 1334 [...] ---- time->Wed Nov 20 12:45:51 2019 type=PROCTITLE msg=audit(1574271951.590:8974): proctitle="./test_verifier" type=SYSCALL msg=audit(1574271951.590:8974): arch=c000003e syscall=321 success=yes exit=14 a0=5 a1=7ffe2d923e80 a2=78 a3=0 items=0 ppid=742 pid=949 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0 ses=2 comm="test_verifier" exe="/root/bpf-next/tools/testing/selftests/bpf/test_verifier" subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null) type=UNKNOWN[1334] msg=audit(1574271951.590:8974): auid=0 uid=0 gid=0 ses=2 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 pid=949 comm="test_verifier" exe="/root/bpf-next/tools/testing/selftests/bpf/test_verifier" prog-id=3260 event=LOAD ---- time->Wed Nov 20 12:45:51 2019 type=UNKNOWN[1334] msg=audit(1574271951.590:8975): prog-id=3260 event=UNLOAD ---- [...] Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20191120213816.8186-1-jolsa@kernel.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/auditsc.c2
-rw-r--r--kernel/bpf/syscall.c31
2 files changed, 32 insertions, 1 deletions
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 4effe01ebbe2..9bf1045fedfa 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2545,7 +2545,7 @@ void __audit_ntp_log(const struct audit_ntp_data *ad)
audit_log_ntp_val(ad, "adjust", AUDIT_NTP_ADJUST);
}
-static void audit_log_task(struct audit_buffer *ab)
+void audit_log_task(struct audit_buffer *ab)
{
kuid_t auid, uid;
kgid_t gid;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index bac3becf9f90..17f4254495f2 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -23,6 +23,7 @@
#include <linux/timekeeping.h>
#include <linux/ctype.h>
#include <linux/nospec.h>
+#include <linux/audit.h>
#include <uapi/linux/btf.h>
#define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY || \
@@ -1318,6 +1319,34 @@ static void free_used_maps(struct bpf_prog_aux *aux)
kfree(aux->used_maps);
}
+enum bpf_event {
+ BPF_EVENT_LOAD,
+ BPF_EVENT_UNLOAD,
+};
+
+static const char * const bpf_event_audit_str[] = {
+ [BPF_EVENT_LOAD] = "LOAD",
+ [BPF_EVENT_UNLOAD] = "UNLOAD",
+};
+
+static void bpf_audit_prog(const struct bpf_prog *prog, enum bpf_event event)
+{
+ bool has_task_context = event == BPF_EVENT_LOAD;
+ struct audit_buffer *ab;
+
+ if (audit_enabled == AUDIT_OFF)
+ return;
+ ab = audit_log_start(audit_context(), GFP_ATOMIC, AUDIT_BPF);
+ if (unlikely(!ab))
+ return;
+ if (has_task_context)
+ audit_log_task(ab);
+ audit_log_format(ab, "%sprog-id=%u event=%s",
+ has_task_context ? " " : "",
+ prog->aux->id, bpf_event_audit_str[event]);
+ audit_log_end(ab);
+}
+
int __bpf_prog_charge(struct user_struct *user, u32 pages)
{
unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
@@ -1434,6 +1463,7 @@ static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
{
if (atomic64_dec_and_test(&prog->aux->refcnt)) {
perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0);
+ bpf_audit_prog(prog, BPF_EVENT_UNLOAD);
/* bpf_prog_free_id() must be called first */
bpf_prog_free_id(prog, do_idr_lock);
__bpf_prog_put_noref(prog, true);
@@ -1843,6 +1873,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
*/
bpf_prog_kallsyms_add(prog);
perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_LOAD, 0);
+ bpf_audit_prog(prog, BPF_EVENT_LOAD);
err = bpf_prog_new_fd(prog);
if (err < 0)