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authorDaniel Borkmann2019-12-06 22:49:34 +0100
committerDaniel Borkmann2019-12-11 17:41:09 +0100
commitbae141f54be83b06652c1d47e50e4e75ed4e9c7e (patch)
tree09b1716fe1145eab1023d1b3a84b683c87ee76a0 /kernel
parentb590cb5f802dc20c72f507f7fbe6737222d0afba (diff)
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 27 16:04:13 2019 type=PROCTITLE msg=audit(1574867053.120:84664): proctitle="./bpf" type=SYSCALL msg=audit(1574867053.120:84664): arch=c000003e syscall=321 \ success=yes exit=3 a0=5 a1=7ffea484fbe0 a2=70 a3=0 items=0 ppid=7477 \ pid=12698 auid=1001 uid=1001 gid=1001 euid=1001 suid=1001 fsuid=1001 \ egid=1001 sgid=1001 fsgid=1001 tty=pts2 ses=4 comm="bpf" \ exe="/home/jolsa/auditd/audit-testsuite/tests/bpf/bpf" \ subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null) type=UNKNOWN[1334] msg=audit(1574867053.120:84664): prog-id=76 op=LOAD ---- time->Wed Nov 27 16:04:13 2019 type=UNKNOWN[1334] msg=audit(1574867053.120:84665): prog-id=76 op=UNLOAD ... Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Co-developed-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Paul Moore <paul@paul-moore.com> Link: https://lore.kernel.org/bpf/20191206214934.11319-1-jolsa@kernel.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/syscall.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index e3461ec59570..66b90eaf99fe 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_PERF_EVENT_ARRAY || \
@@ -1306,6 +1307,36 @@ static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
return 0;
}
+enum bpf_audit {
+ BPF_AUDIT_LOAD,
+ BPF_AUDIT_UNLOAD,
+ BPF_AUDIT_MAX,
+};
+
+static const char * const bpf_audit_str[BPF_AUDIT_MAX] = {
+ [BPF_AUDIT_LOAD] = "LOAD",
+ [BPF_AUDIT_UNLOAD] = "UNLOAD",
+};
+
+static void bpf_audit_prog(const struct bpf_prog *prog, unsigned int op)
+{
+ struct audit_context *ctx = NULL;
+ struct audit_buffer *ab;
+
+ if (WARN_ON_ONCE(op >= BPF_AUDIT_MAX))
+ return;
+ if (audit_enabled == AUDIT_OFF)
+ return;
+ if (op == BPF_AUDIT_LOAD)
+ ctx = audit_context();
+ ab = audit_log_start(ctx, GFP_ATOMIC, AUDIT_BPF);
+ if (unlikely(!ab))
+ return;
+ audit_log_format(ab, "prog-id=%u op=%s",
+ prog->aux->id, bpf_audit_str[op]);
+ audit_log_end(ab);
+}
+
int __bpf_prog_charge(struct user_struct *user, u32 pages)
{
unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
@@ -1421,6 +1452,7 @@ 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_AUDIT_UNLOAD);
/* bpf_prog_free_id() must be called first */
bpf_prog_free_id(prog, do_idr_lock);
__bpf_prog_put_noref(prog, true);
@@ -1830,6 +1862,7 @@ 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_AUDIT_LOAD);
err = bpf_prog_new_fd(prog);
if (err < 0)