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-rw-r--r--include/linux/bpf-cgroup.h13
-rw-r--r--include/uapi/linux/bpf.h7
-rw-r--r--kernel/bpf/cgroup.c59
-rw-r--r--kernel/bpf/syscall.c20
-rw-r--r--kernel/cgroup.c9
-rw-r--r--samples/bpf/test_cgrp2_attach.c2
-rw-r--r--samples/bpf/test_cgrp2_attach2.c68
-rw-r--r--samples/bpf/test_cgrp2_sock.c2
-rw-r--r--samples/bpf/test_cgrp2_sock2.c2
-rw-r--r--tools/lib/bpf/bpf.c4
-rw-r--r--tools/lib/bpf/bpf.h3
11 files changed, 151 insertions, 38 deletions
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 92bc89ae7e20..c970a25d2a49 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -21,20 +21,19 @@ struct cgroup_bpf {
*/
struct bpf_prog *prog[MAX_BPF_ATTACH_TYPE];
struct bpf_prog __rcu *effective[MAX_BPF_ATTACH_TYPE];
+ bool disallow_override[MAX_BPF_ATTACH_TYPE];
};
void cgroup_bpf_put(struct cgroup *cgrp);
void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent);
-void __cgroup_bpf_update(struct cgroup *cgrp,
- struct cgroup *parent,
- struct bpf_prog *prog,
- enum bpf_attach_type type);
+int __cgroup_bpf_update(struct cgroup *cgrp, struct cgroup *parent,
+ struct bpf_prog *prog, enum bpf_attach_type type,
+ bool overridable);
/* Wrapper for __cgroup_bpf_update() protected by cgroup_mutex */
-void cgroup_bpf_update(struct cgroup *cgrp,
- struct bpf_prog *prog,
- enum bpf_attach_type type);
+int cgroup_bpf_update(struct cgroup *cgrp, struct bpf_prog *prog,
+ enum bpf_attach_type type, bool overridable);
int __cgroup_bpf_run_filter_skb(struct sock *sk,
struct sk_buff *skb,
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0eb0e87dbe9f..d2b0ac799d03 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -116,6 +116,12 @@ enum bpf_attach_type {
#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
+/* If BPF_F_ALLOW_OVERRIDE flag is used in BPF_PROG_ATTACH command
+ * to the given target_fd cgroup the descendent cgroup will be able to
+ * override effective bpf program that was inherited from this cgroup
+ */
+#define BPF_F_ALLOW_OVERRIDE (1U << 0)
+
#define BPF_PSEUDO_MAP_FD 1
/* flags for BPF_MAP_UPDATE_ELEM command */
@@ -171,6 +177,7 @@ union bpf_attr {
__u32 target_fd; /* container object to attach to */
__u32 attach_bpf_fd; /* eBPF program to attach */
__u32 attach_type;
+ __u32 attach_flags;
};
} __attribute__((aligned(8)));
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index a515f7b007c6..da0f53690295 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -52,6 +52,7 @@ void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
e = rcu_dereference_protected(parent->bpf.effective[type],
lockdep_is_held(&cgroup_mutex));
rcu_assign_pointer(cgrp->bpf.effective[type], e);
+ cgrp->bpf.disallow_override[type] = parent->bpf.disallow_override[type];
}
}
@@ -82,30 +83,63 @@ void cgroup_bpf_inherit(struct cgroup *cgrp, struct cgroup *parent)
*
* Must be called with cgroup_mutex held.
*/
-void __cgroup_bpf_update(struct cgroup *cgrp,
- struct cgroup *parent,
- struct bpf_prog *prog,
- enum bpf_attach_type type)
+int __cgroup_bpf_update(struct cgroup *cgrp, struct cgroup *parent,
+ struct bpf_prog *prog, enum bpf_attach_type type,
+ bool new_overridable)
{
- struct bpf_prog *old_prog, *effective;
+ struct bpf_prog *old_prog, *effective = NULL;
struct cgroup_subsys_state *pos;
+ bool overridable = true;
- old_prog = xchg(cgrp->bpf.prog + type, prog);
+ if (parent) {
+ overridable = !parent->bpf.disallow_override[type];
+ effective = rcu_dereference_protected(parent->bpf.effective[type],
+ lockdep_is_held(&cgroup_mutex));
+ }
+
+ if (prog && effective && !overridable)
+ /* if parent has non-overridable prog attached, disallow
+ * attaching new programs to descendent cgroup
+ */
+ return -EPERM;
+
+ if (prog && effective && overridable != new_overridable)
+ /* if parent has overridable prog attached, only
+ * allow overridable programs in descendent cgroup
+ */
+ return -EPERM;
- effective = (!prog && parent) ?
- rcu_dereference_protected(parent->bpf.effective[type],
- lockdep_is_held(&cgroup_mutex)) :
- prog;
+ old_prog = cgrp->bpf.prog[type];
+
+ if (prog) {
+ overridable = new_overridable;
+ effective = prog;
+ if (old_prog &&
+ cgrp->bpf.disallow_override[type] == new_overridable)
+ /* disallow attaching non-overridable on top
+ * of existing overridable in this cgroup
+ * and vice versa
+ */
+ return -EPERM;
+ }
+
+ if (!prog && !old_prog)
+ /* report error when trying to detach and nothing is attached */
+ return -ENOENT;
+
+ cgrp->bpf.prog[type] = prog;
css_for_each_descendant_pre(pos, &cgrp->self) {
struct cgroup *desc = container_of(pos, struct cgroup, self);
/* skip the subtree if the descendant has its own program */
- if (desc->bpf.prog[type] && desc != cgrp)
+ if (desc->bpf.prog[type] && desc != cgrp) {
pos = css_rightmost_descendant(pos);
- else
+ } else {
rcu_assign_pointer(desc->bpf.effective[type],
effective);
+ desc->bpf.disallow_override[type] = !overridable;
+ }
}
if (prog)
@@ -115,6 +149,7 @@ void __cgroup_bpf_update(struct cgroup *cgrp,
bpf_prog_put(old_prog);
static_branch_dec(&cgroup_bpf_enabled_key);
}
+ return 0;
}
/**
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 19b6129eab23..bbb016adbaeb 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -920,13 +920,14 @@ static int bpf_obj_get(const union bpf_attr *attr)
#ifdef CONFIG_CGROUP_BPF
-#define BPF_PROG_ATTACH_LAST_FIELD attach_type
+#define BPF_PROG_ATTACH_LAST_FIELD attach_flags
static int bpf_prog_attach(const union bpf_attr *attr)
{
+ enum bpf_prog_type ptype;
struct bpf_prog *prog;
struct cgroup *cgrp;
- enum bpf_prog_type ptype;
+ int ret;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
@@ -934,6 +935,9 @@ static int bpf_prog_attach(const union bpf_attr *attr)
if (CHECK_ATTR(BPF_PROG_ATTACH))
return -EINVAL;
+ if (attr->attach_flags & ~BPF_F_ALLOW_OVERRIDE)
+ return -EINVAL;
+
switch (attr->attach_type) {
case BPF_CGROUP_INET_INGRESS:
case BPF_CGROUP_INET_EGRESS:
@@ -956,10 +960,13 @@ static int bpf_prog_attach(const union bpf_attr *attr)
return PTR_ERR(cgrp);
}
- cgroup_bpf_update(cgrp, prog, attr->attach_type);
+ ret = cgroup_bpf_update(cgrp, prog, attr->attach_type,
+ attr->attach_flags & BPF_F_ALLOW_OVERRIDE);
+ if (ret)
+ bpf_prog_put(prog);
cgroup_put(cgrp);
- return 0;
+ return ret;
}
#define BPF_PROG_DETACH_LAST_FIELD attach_type
@@ -967,6 +974,7 @@ static int bpf_prog_attach(const union bpf_attr *attr)
static int bpf_prog_detach(const union bpf_attr *attr)
{
struct cgroup *cgrp;
+ int ret;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
@@ -982,7 +990,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
if (IS_ERR(cgrp))
return PTR_ERR(cgrp);
- cgroup_bpf_update(cgrp, NULL, attr->attach_type);
+ ret = cgroup_bpf_update(cgrp, NULL, attr->attach_type, false);
cgroup_put(cgrp);
break;
@@ -990,7 +998,7 @@ static int bpf_prog_detach(const union bpf_attr *attr)
return -EINVAL;
}
- return 0;
+ return ret;
}
#endif /* CONFIG_CGROUP_BPF */
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 688dd02af985..53bbca7c4859 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6498,15 +6498,16 @@ static __init int cgroup_namespaces_init(void)
subsys_initcall(cgroup_namespaces_init);
#ifdef CONFIG_CGROUP_BPF
-void cgroup_bpf_update(struct cgroup *cgrp,
- struct bpf_prog *prog,
- enum bpf_attach_type type)
+int cgroup_bpf_update(struct cgroup *cgrp, struct bpf_prog *prog,
+ enum bpf_attach_type type, bool overridable)
{
struct cgroup *parent = cgroup_parent(cgrp);
+ int ret;
mutex_lock(&cgroup_mutex);
- __cgroup_bpf_update(cgrp, parent, prog, type);
+ ret = __cgroup_bpf_update(cgrp, parent, prog, type, overridable);
mutex_unlock(&cgroup_mutex);
+ return ret;
}
#endif /* CONFIG_CGROUP_BPF */
diff --git a/samples/bpf/test_cgrp2_attach.c b/samples/bpf/test_cgrp2_attach.c
index 504058631ffc..4bfcaf93fcf3 100644
--- a/samples/bpf/test_cgrp2_attach.c
+++ b/samples/bpf/test_cgrp2_attach.c
@@ -104,7 +104,7 @@ static int attach_filter(int cg_fd, int type, int verdict)
return EXIT_FAILURE;
}
- ret = bpf_prog_attach(prog_fd, cg_fd, type);
+ ret = bpf_prog_attach(prog_fd, cg_fd, type, 0);
if (ret < 0) {
printf("Failed to attach prog to cgroup: '%s'\n",
strerror(errno));
diff --git a/samples/bpf/test_cgrp2_attach2.c b/samples/bpf/test_cgrp2_attach2.c
index 6e69be37f87f..3049b1f26267 100644
--- a/samples/bpf/test_cgrp2_attach2.c
+++ b/samples/bpf/test_cgrp2_attach2.c
@@ -79,11 +79,12 @@ int main(int argc, char **argv)
if (join_cgroup(FOO))
goto err;
- if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS)) {
+ if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 1)) {
log_err("Attaching prog to /foo");
goto err;
}
+ printf("Attached DROP prog. This ping in cgroup /foo should fail...\n");
assert(system(PING_CMD) != 0);
/* Create cgroup /foo/bar, get fd, and join it */
@@ -94,24 +95,27 @@ int main(int argc, char **argv)
if (join_cgroup(BAR))
goto err;
+ printf("Attached DROP prog. This ping in cgroup /foo/bar should fail...\n");
assert(system(PING_CMD) != 0);
- if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS)) {
+ if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
log_err("Attaching prog to /foo/bar");
goto err;
}
+ printf("Attached PASS prog. This ping in cgroup /foo/bar should pass...\n");
assert(system(PING_CMD) == 0);
-
if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
log_err("Detaching program from /foo/bar");
goto err;
}
+ printf("Detached PASS from /foo/bar while DROP is attached to /foo.\n"
+ "This ping in cgroup /foo/bar should fail...\n");
assert(system(PING_CMD) != 0);
- if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS)) {
+ if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
log_err("Attaching prog to /foo/bar");
goto err;
}
@@ -121,8 +125,60 @@ int main(int argc, char **argv)
goto err;
}
+ printf("Attached PASS from /foo/bar and detached DROP from /foo.\n"
+ "This ping in cgroup /foo/bar should pass...\n");
assert(system(PING_CMD) == 0);
+ if (bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
+ log_err("Attaching prog to /foo/bar");
+ goto err;
+ }
+
+ if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
+ errno = 0;
+ log_err("Unexpected success attaching prog to /foo/bar");
+ goto err;
+ }
+
+ if (bpf_prog_detach(bar, BPF_CGROUP_INET_EGRESS)) {
+ log_err("Detaching program from /foo/bar");
+ goto err;
+ }
+
+ if (!bpf_prog_detach(foo, BPF_CGROUP_INET_EGRESS)) {
+ errno = 0;
+ log_err("Unexpected success in double detach from /foo");
+ goto err;
+ }
+
+ if (bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
+ log_err("Attaching non-overridable prog to /foo");
+ goto err;
+ }
+
+ if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 0)) {
+ errno = 0;
+ log_err("Unexpected success attaching non-overridable prog to /foo/bar");
+ goto err;
+ }
+
+ if (!bpf_prog_attach(allow_prog, bar, BPF_CGROUP_INET_EGRESS, 1)) {
+ errno = 0;
+ log_err("Unexpected success attaching overridable prog to /foo/bar");
+ goto err;
+ }
+
+ if (!bpf_prog_attach(allow_prog, foo, BPF_CGROUP_INET_EGRESS, 1)) {
+ errno = 0;
+ log_err("Unexpected success attaching overridable prog to /foo");
+ goto err;
+ }
+
+ if (bpf_prog_attach(drop_prog, foo, BPF_CGROUP_INET_EGRESS, 0)) {
+ log_err("Attaching different non-overridable prog to /foo");
+ goto err;
+ }
+
goto out;
err:
@@ -132,5 +188,9 @@ out:
close(foo);
close(bar);
cleanup_cgroup_environment();
+ if (!rc)
+ printf("PASS\n");
+ else
+ printf("FAIL\n");
return rc;
}
diff --git a/samples/bpf/test_cgrp2_sock.c b/samples/bpf/test_cgrp2_sock.c
index 0791b949cbe4..c3cfb23e23b5 100644
--- a/samples/bpf/test_cgrp2_sock.c
+++ b/samples/bpf/test_cgrp2_sock.c
@@ -75,7 +75,7 @@ int main(int argc, char **argv)
return EXIT_FAILURE;
}
- ret = bpf_prog_attach(prog_fd, cg_fd, BPF_CGROUP_INET_SOCK_CREATE);
+ ret = bpf_prog_attach(prog_fd, cg_fd, BPF_CGROUP_INET_SOCK_CREATE, 0);
if (ret < 0) {
printf("Failed to attach prog to cgroup: '%s'\n",
strerror(errno));
diff --git a/samples/bpf/test_cgrp2_sock2.c b/samples/bpf/test_cgrp2_sock2.c
index 455ef0d06e93..db036077b644 100644
--- a/samples/bpf/test_cgrp2_sock2.c
+++ b/samples/bpf/test_cgrp2_sock2.c
@@ -55,7 +55,7 @@ int main(int argc, char **argv)
}
ret = bpf_prog_attach(prog_fd[filter_id], cg_fd,
- BPF_CGROUP_INET_SOCK_CREATE);
+ BPF_CGROUP_INET_SOCK_CREATE, 0);
if (ret < 0) {
printf("Failed to attach prog to cgroup: '%s'\n",
strerror(errno));
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 3ddb58a36d3c..ae752fa4eaa7 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -168,7 +168,8 @@ int bpf_obj_get(const char *pathname)
return sys_bpf(BPF_OBJ_GET, &attr, sizeof(attr));
}
-int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type)
+int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type,
+ unsigned int flags)
{
union bpf_attr attr;
@@ -176,6 +177,7 @@ int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type)
attr.target_fd = target_fd;
attr.attach_bpf_fd = prog_fd;
attr.attach_type = type;
+ attr.attach_flags = flags;
return sys_bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index a2f9853dd882..4ac6c4b84100 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -41,7 +41,8 @@ int bpf_map_delete_elem(int fd, void *key);
int bpf_map_get_next_key(int fd, void *key, void *next_key);
int bpf_obj_pin(int fd, const char *pathname);
int bpf_obj_get(const char *pathname);
-int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type);
+int bpf_prog_attach(int prog_fd, int attachable_fd, enum bpf_attach_type type,
+ unsigned int flags);
int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);
generated by cgit (git 2.34.1) at 2024-05-09 14:28:19 +0000