From a77f059f66f68404ad043075bc29fe101945405b Mon Sep 17 00:00:00 2001
From: Luis Gerhorst <privat@luisgerhorst.de>
Date: Sun, 4 Jul 2021 12:08:17 +0200
Subject: [PATCH] task_find: direct packet access
---
libbpf | 2 +-
src/task_find.bpf.c | 20 +++++++++++++++-----
src/task_find.c | 4 +++-
3 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/libbpf b/libbpf
index a258324..e6fdf39 160000
--- a/libbpf
+++ b/libbpf
@@ -1 +1 @@
-Subproject commit a2583241a0cfe897a924acf7c666846f1ec3bda5
+Subproject commit e6fdf39f4c704221159e9f45f27a3ec6d56cfd4b
diff --git a/src/task_find.bpf.c b/src/task_find.bpf.c
index 190a303..a0f8244 100644
--- a/src/task_find.bpf.c
+++ b/src/task_find.bpf.c
@@ -22,8 +22,8 @@ int entry(void *ctx)
{
int err = 0;
- char root_path[256];
- err = bpf_probe_read_user(root_path, 256, root_path_user);
+ char root_path[PATHLEN];
+ err = bpf_probe_read_user(root_path, PATHLEN, root_path_user);
if (err) {
bpf_printk("Error: read_user = %d", err);
goto end;
@@ -63,7 +63,19 @@ SEC("iterdents64")
int process_dirent(struct bpf_dirent64 *d) {
int err = 0;
- if (d->namelen <= 2) {
+ /* Skip "." and "..": */
+ /* TODO: Why doesn't the verifier get this? */
+ if (d->name + 2 > d->name_end) {
+ goto end;
+ }
+ if (d->name[0] == '.' && d->namelen == 1) {
+ goto end;
+ }
+
+ if (d->name + 3 > d->name_end) {
+ goto end;
+ }
+ if (d->name[0] == '.' && d->name[1] == '.' && d->namelen == 2) {
goto end;
}
@@ -72,8 +84,6 @@ int process_dirent(struct bpf_dirent64 *d) {
goto end;
}
- bpf_printk("iterating %d/%s", d->dfd, d->name);
-
int *prog_fd = bpf_map_lookup_elem(&pdpf_map, &PDPF_KEY);
if (!prog_fd) {
bpf_printk("Error: !bpf_map_lookup_elem(&pdpf_map, &PDPF_KEY)");
diff --git a/src/task_find.c b/src/task_find.c
index 93e3654..21512fc 100644
--- a/src/task_find.c
+++ b/src/task_find.c
@@ -167,7 +167,9 @@ static int bpf_find_by_name(const char *path, const char *name, bool debug) {
return EXIT_FAILURE;
}
- skel->bss->root_path_user = path;
+ char root_path_user[PATHLEN];
+ strncpy(root_path_user, path, PATHLEN);
+ skel->bss->root_path_user = root_path_user;
/* Load & verify BPF programs */
err = BPF_LOAD(skel);
--
GitLab