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-rw-r--r--kernel/bpf/trampoline.c610
1 files changed, 486 insertions, 124 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index e98de5e73ba5..bf0906e1e2b9 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -11,6 +11,9 @@
#include <linux/rcupdate_wait.h>
#include <linux/module.h>
#include <linux/static_call.h>
+#include <linux/bpf_verifier.h>
+#include <linux/bpf_lsm.h>
+#include <linux/delay.h>
/* dummy _ops. The verifier will operate on target program's ops. */
const struct bpf_verifier_ops bpf_extension_verifier_ops = {
@@ -27,20 +30,90 @@ static struct hlist_head trampoline_table[TRAMPOLINE_TABLE_SIZE];
/* serializes access to trampoline_table */
static DEFINE_MUTEX(trampoline_mutex);
-void *bpf_jit_alloc_exec_page(void)
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex);
+
+static int bpf_tramp_ftrace_ops_func(struct ftrace_ops *ops, enum ftrace_ops_cmd cmd)
{
- void *image;
+ struct bpf_trampoline *tr = ops->private;
+ int ret = 0;
- image = bpf_jit_alloc_exec(PAGE_SIZE);
- if (!image)
- return NULL;
+ if (cmd == FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF) {
+ /* This is called inside register_ftrace_direct_multi(), so
+ * tr->mutex is already locked.
+ */
+ lockdep_assert_held_once(&tr->mutex);
- set_vm_flush_reset_perms(image);
- /* Keep image as writeable. The alternative is to keep flipping ro/rw
- * everytime new program is attached or detached.
+ /* Instead of updating the trampoline here, we propagate
+ * -EAGAIN to register_ftrace_direct_multi(). Then we can
+ * retry register_ftrace_direct_multi() after updating the
+ * trampoline.
+ */
+ if ((tr->flags & BPF_TRAMP_F_CALL_ORIG) &&
+ !(tr->flags & BPF_TRAMP_F_ORIG_STACK)) {
+ if (WARN_ON_ONCE(tr->flags & BPF_TRAMP_F_SHARE_IPMODIFY))
+ return -EBUSY;
+
+ tr->flags |= BPF_TRAMP_F_SHARE_IPMODIFY;
+ return -EAGAIN;
+ }
+
+ return 0;
+ }
+
+ /* The normal locking order is
+ * tr->mutex => direct_mutex (ftrace.c) => ftrace_lock (ftrace.c)
+ *
+ * The following two commands are called from
+ *
+ * prepare_direct_functions_for_ipmodify
+ * cleanup_direct_functions_after_ipmodify
+ *
+ * In both cases, direct_mutex is already locked. Use
+ * mutex_trylock(&tr->mutex) to avoid deadlock in race condition
+ * (something else is making changes to this same trampoline).
*/
- set_memory_x((long)image, 1);
- return image;
+ if (!mutex_trylock(&tr->mutex)) {
+ /* sleep 1 ms to make sure whatever holding tr->mutex makes
+ * some progress.
+ */
+ msleep(1);
+ return -EAGAIN;
+ }
+
+ switch (cmd) {
+ case FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER:
+ tr->flags |= BPF_TRAMP_F_SHARE_IPMODIFY;
+
+ if ((tr->flags & BPF_TRAMP_F_CALL_ORIG) &&
+ !(tr->flags & BPF_TRAMP_F_ORIG_STACK))
+ ret = bpf_trampoline_update(tr, false /* lock_direct_mutex */);
+ break;
+ case FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER:
+ tr->flags &= ~BPF_TRAMP_F_SHARE_IPMODIFY;
+
+ if (tr->flags & BPF_TRAMP_F_ORIG_STACK)
+ ret = bpf_trampoline_update(tr, false /* lock_direct_mutex */);
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ mutex_unlock(&tr->mutex);
+ return ret;
+}
+#endif
+
+bool bpf_prog_has_trampoline(const struct bpf_prog *prog)
+{
+ enum bpf_attach_type eatype = prog->expected_attach_type;
+ enum bpf_prog_type ptype = prog->type;
+
+ return (ptype == BPF_PROG_TYPE_TRACING &&
+ (eatype == BPF_TRACE_FENTRY || eatype == BPF_TRACE_FEXIT ||
+ eatype == BPF_MODIFY_RETURN)) ||
+ (ptype == BPF_PROG_TYPE_LSM && eatype == BPF_LSM_MAC);
}
void bpf_image_ksym_add(void *data, struct bpf_ksym *ksym)
@@ -76,6 +149,16 @@ static struct bpf_trampoline *bpf_trampoline_lookup(u64 key)
tr = kzalloc(sizeof(*tr), GFP_KERNEL);
if (!tr)
goto out;
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+ tr->fops = kzalloc(sizeof(struct ftrace_ops), GFP_KERNEL);
+ if (!tr->fops) {
+ kfree(tr);
+ tr = NULL;
+ goto out;
+ }
+ tr->fops->private = tr;
+ tr->fops->ops_func = bpf_tramp_ftrace_ops_func;
+#endif
tr->key = key;
INIT_HLIST_NODE(&tr->hlist);
@@ -109,25 +192,13 @@ static void bpf_trampoline_module_put(struct bpf_trampoline *tr)
tr->mod = NULL;
}
-static int is_ftrace_location(void *ip)
-{
- long addr;
-
- addr = ftrace_location((long)ip);
- if (!addr)
- return 0;
- if (WARN_ON_ONCE(addr != (long)ip))
- return -EFAULT;
- return 1;
-}
-
static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr)
{
void *ip = tr->func.addr;
int ret;
if (tr->func.ftrace_managed)
- ret = unregister_ftrace_direct((long)ip, (long)old_addr);
+ ret = unregister_ftrace_direct_multi(tr->fops, (long)old_addr);
else
ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, NULL);
@@ -136,15 +207,20 @@ static int unregister_fentry(struct bpf_trampoline *tr, void *old_addr)
return ret;
}
-static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_addr)
+static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_addr,
+ bool lock_direct_mutex)
{
void *ip = tr->func.addr;
int ret;
- if (tr->func.ftrace_managed)
- ret = modify_ftrace_direct((long)ip, (long)old_addr, (long)new_addr);
- else
+ if (tr->func.ftrace_managed) {
+ if (lock_direct_mutex)
+ ret = modify_ftrace_direct_multi(tr->fops, (long)new_addr);
+ else
+ ret = modify_ftrace_direct_multi_nolock(tr->fops, (long)new_addr);
+ } else {
ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, old_addr, new_addr);
+ }
return ret;
}
@@ -152,50 +228,55 @@ static int modify_fentry(struct bpf_trampoline *tr, void *old_addr, void *new_ad
static int register_fentry(struct bpf_trampoline *tr, void *new_addr)
{
void *ip = tr->func.addr;
+ unsigned long faddr;
int ret;
- ret = is_ftrace_location(ip);
- if (ret < 0)
- return ret;
- tr->func.ftrace_managed = ret;
+ faddr = ftrace_location((unsigned long)ip);
+ if (faddr) {
+ if (!tr->fops)
+ return -ENOTSUPP;
+ tr->func.ftrace_managed = true;
+ }
if (bpf_trampoline_module_get(tr))
return -ENOENT;
- if (tr->func.ftrace_managed)
- ret = register_ftrace_direct((long)ip, (long)new_addr);
- else
+ if (tr->func.ftrace_managed) {
+ ftrace_set_filter_ip(tr->fops, (unsigned long)ip, 0, 1);
+ ret = register_ftrace_direct_multi(tr->fops, (long)new_addr);
+ } else {
ret = bpf_arch_text_poke(ip, BPF_MOD_CALL, NULL, new_addr);
+ }
if (ret)
bpf_trampoline_module_put(tr);
return ret;
}
-static struct bpf_tramp_progs *
+static struct bpf_tramp_links *
bpf_trampoline_get_progs(const struct bpf_trampoline *tr, int *total, bool *ip_arg)
{
- const struct bpf_prog_aux *aux;
- struct bpf_tramp_progs *tprogs;
- struct bpf_prog **progs;
+ struct bpf_tramp_link *link;
+ struct bpf_tramp_links *tlinks;
+ struct bpf_tramp_link **links;
int kind;
*total = 0;
- tprogs = kcalloc(BPF_TRAMP_MAX, sizeof(*tprogs), GFP_KERNEL);
- if (!tprogs)
+ tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL);
+ if (!tlinks)
return ERR_PTR(-ENOMEM);
for (kind = 0; kind < BPF_TRAMP_MAX; kind++) {
- tprogs[kind].nr_progs = tr->progs_cnt[kind];
+ tlinks[kind].nr_links = tr->progs_cnt[kind];
*total += tr->progs_cnt[kind];
- progs = tprogs[kind].progs;
+ links = tlinks[kind].links;
- hlist_for_each_entry(aux, &tr->progs_hlist[kind], tramp_hlist) {
- *ip_arg |= aux->prog->call_get_func_ip;
- *progs++ = aux->prog;
+ hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) {
+ *ip_arg |= link->link.prog->call_get_func_ip;
+ *links++ = link;
}
}
- return tprogs;
+ return tlinks;
}
static void __bpf_tramp_image_put_deferred(struct work_struct *work)
@@ -205,7 +286,7 @@ static void __bpf_tramp_image_put_deferred(struct work_struct *work)
im = container_of(work, struct bpf_tramp_image, work);
bpf_image_ksym_del(&im->ksym);
bpf_jit_free_exec(im->image);
- bpf_jit_uncharge_modmem(1);
+ bpf_jit_uncharge_modmem(PAGE_SIZE);
percpu_ref_exit(&im->pcref);
kfree_rcu(im, rcu);
}
@@ -302,14 +383,15 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
if (!im)
goto out;
- err = bpf_jit_charge_modmem(1);
+ err = bpf_jit_charge_modmem(PAGE_SIZE);
if (err)
goto out_free_im;
err = -ENOMEM;
- im->image = image = bpf_jit_alloc_exec_page();
+ im->image = image = bpf_jit_alloc_exec(PAGE_SIZE);
if (!image)
goto out_uncharge;
+ set_vm_flush_reset_perms(image);
err = percpu_ref_init(&im->pcref, __bpf_tramp_image_release, 0, GFP_KERNEL);
if (err)
@@ -324,24 +406,24 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, u32 idx)
out_free_image:
bpf_jit_free_exec(im->image);
out_uncharge:
- bpf_jit_uncharge_modmem(1);
+ bpf_jit_uncharge_modmem(PAGE_SIZE);
out_free_im:
kfree(im);
out:
return ERR_PTR(err);
}
-static int bpf_trampoline_update(struct bpf_trampoline *tr)
+static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mutex)
{
struct bpf_tramp_image *im;
- struct bpf_tramp_progs *tprogs;
- u32 flags = BPF_TRAMP_F_RESTORE_REGS;
+ struct bpf_tramp_links *tlinks;
+ u32 orig_flags = tr->flags;
bool ip_arg = false;
int err, total;
- tprogs = bpf_trampoline_get_progs(tr, &total, &ip_arg);
- if (IS_ERR(tprogs))
- return PTR_ERR(tprogs);
+ tlinks = bpf_trampoline_get_progs(tr, &total, &ip_arg);
+ if (IS_ERR(tlinks))
+ return PTR_ERR(tlinks);
if (total == 0) {
err = unregister_fentry(tr, tr->cur_image->image);
@@ -357,35 +439,71 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr)
goto out;
}
- if (tprogs[BPF_TRAMP_FEXIT].nr_progs ||
- tprogs[BPF_TRAMP_MODIFY_RETURN].nr_progs)
- flags = BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME;
+ /* clear all bits except SHARE_IPMODIFY */
+ tr->flags &= BPF_TRAMP_F_SHARE_IPMODIFY;
+
+ if (tlinks[BPF_TRAMP_FEXIT].nr_links ||
+ tlinks[BPF_TRAMP_MODIFY_RETURN].nr_links) {
+ /* NOTE: BPF_TRAMP_F_RESTORE_REGS and BPF_TRAMP_F_SKIP_FRAME
+ * should not be set together.
+ */
+ tr->flags |= BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_SKIP_FRAME;
+ } else {
+ tr->flags |= BPF_TRAMP_F_RESTORE_REGS;
+ }
if (ip_arg)
- flags |= BPF_TRAMP_F_IP_ARG;
+ tr->flags |= BPF_TRAMP_F_IP_ARG;
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+again:
+ if ((tr->flags & BPF_TRAMP_F_SHARE_IPMODIFY) &&
+ (tr->flags & BPF_TRAMP_F_CALL_ORIG))
+ tr->flags |= BPF_TRAMP_F_ORIG_STACK;
+#endif
err = arch_prepare_bpf_trampoline(im, im->image, im->image + PAGE_SIZE,
- &tr->func.model, flags, tprogs,
+ &tr->func.model, tr->flags, tlinks,
tr->func.addr);
if (err < 0)
goto out;
+ set_memory_ro((long)im->image, 1);
+ set_memory_x((long)im->image, 1);
+
WARN_ON(tr->cur_image && tr->selector == 0);
WARN_ON(!tr->cur_image && tr->selector);
if (tr->cur_image)
/* progs already running at this address */
- err = modify_fentry(tr, tr->cur_image->image, im->image);
+ err = modify_fentry(tr, tr->cur_image->image, im->image, lock_direct_mutex);
else
/* first time registering */
err = register_fentry(tr, im->image);
+
+#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
+ if (err == -EAGAIN) {
+ /* -EAGAIN from bpf_tramp_ftrace_ops_func. Now
+ * BPF_TRAMP_F_SHARE_IPMODIFY is set, we can generate the
+ * trampoline again, and retry register.
+ */
+ /* reset fops->func and fops->trampoline for re-register */
+ tr->fops->func = NULL;
+ tr->fops->trampoline = 0;
+ goto again;
+ }
+#endif
if (err)
goto out;
+
if (tr->cur_image)
bpf_tramp_image_put(tr->cur_image);
tr->cur_image = im;
tr->selector++;
out:
- kfree(tprogs);
+ /* If any error happens, restore previous flags */
+ if (err)
+ tr->flags = orig_flags;
+ kfree(tlinks);
return err;
}
@@ -411,77 +529,264 @@ static enum bpf_tramp_prog_type bpf_attach_type_to_tramp(struct bpf_prog *prog)
}
}
-int bpf_trampoline_link_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
+static int __bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
{
enum bpf_tramp_prog_type kind;
+ struct bpf_tramp_link *link_exiting;
int err = 0;
- int cnt;
+ int cnt = 0, i;
- kind = bpf_attach_type_to_tramp(prog);
- mutex_lock(&tr->mutex);
- if (tr->extension_prog) {
+ kind = bpf_attach_type_to_tramp(link->link.prog);
+ if (tr->extension_prog)
/* cannot attach fentry/fexit if extension prog is attached.
* cannot overwrite extension prog either.
*/
- err = -EBUSY;
- goto out;
- }
- cnt = tr->progs_cnt[BPF_TRAMP_FENTRY] + tr->progs_cnt[BPF_TRAMP_FEXIT];
+ return -EBUSY;
+
+ for (i = 0; i < BPF_TRAMP_MAX; i++)
+ cnt += tr->progs_cnt[i];
+
if (kind == BPF_TRAMP_REPLACE) {
/* Cannot attach extension if fentry/fexit are in use. */
- if (cnt) {
- err = -EBUSY;
- goto out;
- }
- tr->extension_prog = prog;
- err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL,
- prog->bpf_func);
- goto out;
+ if (cnt)
+ return -EBUSY;
+ tr->extension_prog = link->link.prog;
+ return bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP, NULL,
+ link->link.prog->bpf_func);
}
- if (cnt >= BPF_MAX_TRAMP_PROGS) {
- err = -E2BIG;
- goto out;
- }
- if (!hlist_unhashed(&prog->aux->tramp_hlist)) {
+ if (cnt >= BPF_MAX_TRAMP_LINKS)
+ return -E2BIG;
+ if (!hlist_unhashed(&link->tramp_hlist))
/* prog already linked */
- err = -EBUSY;
- goto out;
+ return -EBUSY;
+ hlist_for_each_entry(link_exiting, &tr->progs_hlist[kind], tramp_hlist) {
+ if (link_exiting->link.prog != link->link.prog)
+ continue;
+ /* prog already linked */
+ return -EBUSY;
}
- hlist_add_head(&prog->aux->tramp_hlist, &tr->progs_hlist[kind]);
+
+ hlist_add_head(&link->tramp_hlist, &tr->progs_hlist[kind]);
tr->progs_cnt[kind]++;
- err = bpf_trampoline_update(tr);
+ err = bpf_trampoline_update(tr, true /* lock_direct_mutex */);
if (err) {
- hlist_del_init(&prog->aux->tramp_hlist);
+ hlist_del_init(&link->tramp_hlist);
tr->progs_cnt[kind]--;
}
-out:
+ return err;
+}
+
+int bpf_trampoline_link_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+ int err;
+
+ mutex_lock(&tr->mutex);
+ err = __bpf_trampoline_link_prog(link, tr);
mutex_unlock(&tr->mutex);
return err;
}
-/* bpf_trampoline_unlink_prog() should never fail. */
-int bpf_trampoline_unlink_prog(struct bpf_prog *prog, struct bpf_trampoline *tr)
+static int __bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
{
enum bpf_tramp_prog_type kind;
int err;
- kind = bpf_attach_type_to_tramp(prog);
- mutex_lock(&tr->mutex);
+ kind = bpf_attach_type_to_tramp(link->link.prog);
if (kind == BPF_TRAMP_REPLACE) {
WARN_ON_ONCE(!tr->extension_prog);
err = bpf_arch_text_poke(tr->func.addr, BPF_MOD_JUMP,
tr->extension_prog->bpf_func, NULL);
tr->extension_prog = NULL;
- goto out;
+ return err;
}
- hlist_del_init(&prog->aux->tramp_hlist);
+ hlist_del_init(&link->tramp_hlist);
tr->progs_cnt[kind]--;
- err = bpf_trampoline_update(tr);
-out:
+ return bpf_trampoline_update(tr, true /* lock_direct_mutex */);
+}
+
+/* bpf_trampoline_unlink_prog() should never fail. */
+int bpf_trampoline_unlink_prog(struct bpf_tramp_link *link, struct bpf_trampoline *tr)
+{
+ int err;
+
+ mutex_lock(&tr->mutex);
+ err = __bpf_trampoline_unlink_prog(link, tr);
+ mutex_unlock(&tr->mutex);
+ return err;
+}
+
+#if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM)
+static void bpf_shim_tramp_link_release(struct bpf_link *link)
+{
+ struct bpf_shim_tramp_link *shim_link =
+ container_of(link, struct bpf_shim_tramp_link, link.link);
+
+ /* paired with 'shim_link->trampoline = tr' in bpf_trampoline_link_cgroup_shim */
+ if (!shim_link->trampoline)
+ return;
+
+ WARN_ON_ONCE(bpf_trampoline_unlink_prog(&shim_link->link, shim_link->trampoline));
+ bpf_trampoline_put(shim_link->trampoline);
+}
+
+static void bpf_shim_tramp_link_dealloc(struct bpf_link *link)
+{
+ struct bpf_shim_tramp_link *shim_link =
+ container_of(link, struct bpf_shim_tramp_link, link.link);
+
+ kfree(shim_link);
+}
+
+static const struct bpf_link_ops bpf_shim_tramp_link_lops = {
+ .release = bpf_shim_tramp_link_release,
+ .dealloc = bpf_shim_tramp_link_dealloc,
+};
+
+static struct bpf_shim_tramp_link *cgroup_shim_alloc(const struct bpf_prog *prog,
+ bpf_func_t bpf_func,
+ int cgroup_atype)
+{
+ struct bpf_shim_tramp_link *shim_link = NULL;
+ struct bpf_prog *p;
+
+ shim_link = kzalloc(sizeof(*shim_link), GFP_USER);
+ if (!shim_link)
+ return NULL;
+
+ p = bpf_prog_alloc(1, 0);
+ if (!p) {
+ kfree(shim_link);
+ return NULL;
+ }
+
+ p->jited = false;
+ p->bpf_func = bpf_func;
+
+ p->aux->cgroup_atype = cgroup_atype;
+ p->aux->attach_func_proto = prog->aux->attach_func_proto;
+ p->aux->attach_btf_id = prog->aux->attach_btf_id;
+ p->aux->attach_btf = prog->aux->attach_btf;
+ btf_get(p->aux->attach_btf);
+ p->type = BPF_PROG_TYPE_LSM;
+ p->expected_attach_type = BPF_LSM_MAC;
+ bpf_prog_inc(p);
+ bpf_link_init(&shim_link->link.link, BPF_LINK_TYPE_UNSPEC,
+ &bpf_shim_tramp_link_lops, p);
+ bpf_cgroup_atype_get(p->aux->attach_btf_id, cgroup_atype);
+
+ return shim_link;
+}
+
+static struct bpf_shim_tramp_link *cgroup_shim_find(struct bpf_trampoline *tr,
+ bpf_func_t bpf_func)
+{
+ struct bpf_tramp_link *link;
+ int kind;
+
+ for (kind = 0; kind < BPF_TRAMP_MAX; kind++) {
+ hlist_for_each_entry(link, &tr->progs_hlist[kind], tramp_hlist) {
+ struct bpf_prog *p = link->link.prog;
+
+ if (p->bpf_func == bpf_func)
+ return container_of(link, struct bpf_shim_tramp_link, link);
+ }
+ }
+
+ return NULL;
+}
+
+int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
+ int cgroup_atype)
+{
+ struct bpf_shim_tramp_link *shim_link = NULL;
+ struct bpf_attach_target_info tgt_info = {};
+ struct bpf_trampoline *tr;
+ bpf_func_t bpf_func;
+ u64 key;
+ int err;
+
+ err = bpf_check_attach_target(NULL, prog, NULL,
+ prog->aux->attach_btf_id,
+ &tgt_info);
+ if (err)
+ return err;
+
+ key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf,
+ prog->aux->attach_btf_id);
+
+ bpf_lsm_find_cgroup_shim(prog, &bpf_func);
+ tr = bpf_trampoline_get(key, &tgt_info);
+ if (!tr)
+ return -ENOMEM;
+
+ mutex_lock(&tr->mutex);
+
+ shim_link = cgroup_shim_find(tr, bpf_func);
+ if (shim_link) {
+ /* Reusing existing shim attached by the other program. */
+ bpf_link_inc(&shim_link->link.link);
+
+ mutex_unlock(&tr->mutex);
+ bpf_trampoline_put(tr); /* bpf_trampoline_get above */
+ return 0;
+ }
+
+ /* Allocate and install new shim. */
+
+ shim_link = cgroup_shim_alloc(prog, bpf_func, cgroup_atype);
+ if (!shim_link) {
+ err = -ENOMEM;
+ goto err;
+ }
+
+ err = __bpf_trampoline_link_prog(&shim_link->link, tr);
+ if (err)
+ goto err;
+
+ shim_link->trampoline = tr;
+ /* note, we're still holding tr refcnt from above */
+
mutex_unlock(&tr->mutex);
+
+ return 0;
+err:
+ mutex_unlock(&tr->mutex);
+
+ if (shim_link)
+ bpf_link_put(&shim_link->link.link);
+
+ /* have to release tr while _not_ holding its mutex */
+ bpf_trampoline_put(tr); /* bpf_trampoline_get above */
+
return err;
}
+void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog)
+{
+ struct bpf_shim_tramp_link *shim_link = NULL;
+ struct bpf_trampoline *tr;
+ bpf_func_t bpf_func;
+ u64 key;
+
+ key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf,
+ prog->aux->attach_btf_id);
+
+ bpf_lsm_find_cgroup_shim(prog, &bpf_func);
+ tr = bpf_trampoline_lookup(key);
+ if (WARN_ON_ONCE(!tr))
+ return;
+
+ mutex_lock(&tr->mutex);
+ shim_link = cgroup_shim_find(tr, bpf_func);
+ mutex_unlock(&tr->mutex);
+
+ if (shim_link)
+ bpf_link_put(&shim_link->link.link);
+
+ bpf_trampoline_put(tr); /* bpf_trampoline_lookup above */
+}
+#endif
+
struct bpf_trampoline *bpf_trampoline_get(u64 key,
struct bpf_attach_target_info *tgt_info)
{
@@ -504,16 +809,19 @@ out:
void bpf_trampoline_put(struct bpf_trampoline *tr)
{
+ int i;
+
if (!tr)
return;
mutex_lock(&trampoline_mutex);
if (!refcount_dec_and_test(&tr->refcnt))
goto out;
WARN_ON_ONCE(mutex_is_locked(&tr->mutex));
- if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[BPF_TRAMP_FENTRY])))
- goto out;
- if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[BPF_TRAMP_FEXIT])))
- goto out;
+
+ for (i = 0; i < BPF_TRAMP_MAX; i++)
+ if (WARN_ON_ONCE(!hlist_empty(&tr->progs_hlist[i])))
+ goto out;
+
/* This code will be executed even when the last bpf_tramp_image
* is alive. All progs are detached from the trampoline and the
* trampoline image is patched with jmp into epilogue to skip
@@ -521,6 +829,10 @@ void bpf_trampoline_put(struct bpf_trampoline *tr)
* multiple rcu callbacks.
*/
hlist_del(&tr->hlist);
+ if (tr->fops) {
+ ftrace_free_filter(tr->fops);
+ kfree(tr->fops);
+ }
kfree(tr);
out:
mutex_unlock(&trampoline_mutex);
@@ -539,16 +851,6 @@ static __always_inline u64 notrace bpf_prog_start_time(void)
return start;
}
-static void notrace inc_misses_counter(struct bpf_prog *prog)
-{
- struct bpf_prog_stats *stats;
-
- stats = this_cpu_ptr(prog->stats);
- u64_stats_update_begin(&stats->syncp);
- u64_stats_inc(&stats->misses);
- u64_stats_update_end(&stats->syncp);
-}
-
/* The logic is similar to bpf_prog_run(), but with an explicit
* rcu_read_lock() and migrate_disable() which are required
* for the trampoline. The macro is split into
@@ -562,13 +864,16 @@ static void notrace inc_misses_counter(struct bpf_prog *prog)
* [2..MAX_U64] - execute bpf prog and record execution time.
* This is start time.
*/
-u64 notrace __bpf_prog_enter(struct bpf_prog *prog)
+u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
__acquires(RCU)
{
rcu_read_lock();
migrate_disable();
- if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
- inc_misses_counter(prog);
+
+ run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+ if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
+ bpf_prog_inc_misses_counter(prog);
return 0;
}
return bpf_prog_start_time();
@@ -596,35 +901,92 @@ static void notrace update_prog_stats(struct bpf_prog *prog,
}
}
-void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start)
+void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, struct bpf_tramp_run_ctx *run_ctx)
__releases(RCU)
{
+ bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
update_prog_stats(prog, start);
- __this_cpu_dec(*(prog->active));
+ this_cpu_dec(*(prog->active));
migrate_enable();
rcu_read_unlock();
}
-u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog)
+u64 notrace __bpf_prog_enter_lsm_cgroup(struct bpf_prog *prog,
+ struct bpf_tramp_run_ctx *run_ctx)
+ __acquires(RCU)
+{
+ /* Runtime stats are exported via actual BPF_LSM_CGROUP
+ * programs, not the shims.
+ */
+ rcu_read_lock();
+ migrate_disable();
+
+ run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+ return NO_START_TIME;
+}
+
+void notrace __bpf_prog_exit_lsm_cgroup(struct bpf_prog *prog, u64 start,
+ struct bpf_tramp_run_ctx *run_ctx)
+ __releases(RCU)
+{
+ bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
+ migrate_enable();
+ rcu_read_unlock();
+}
+
+u64 notrace __bpf_prog_enter_sleepable(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx)
{
rcu_read_lock_trace();
migrate_disable();
might_fault();
- if (unlikely(__this_cpu_inc_return(*(prog->active)) != 1)) {
- inc_misses_counter(prog);
+
+ if (unlikely(this_cpu_inc_return(*(prog->active)) != 1)) {
+ bpf_prog_inc_misses_counter(prog);
return 0;
}
+
+ run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
return bpf_prog_start_time();
}
-void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start)
+void notrace __bpf_prog_exit_sleepable(struct bpf_prog *prog, u64 start,
+ struct bpf_tramp_run_ctx *run_ctx)
{
+ bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
update_prog_stats(prog, start);
- __this_cpu_dec(*(prog->active));
+ this_cpu_dec(*(prog->active));
migrate_enable();
rcu_read_unlock_trace();
}
+u64 notrace __bpf_prog_enter_struct_ops(struct bpf_prog *prog,
+ struct bpf_tramp_run_ctx *run_ctx)
+ __acquires(RCU)
+{
+ rcu_read_lock();
+ migrate_disable();
+
+ run_ctx->saved_run_ctx = bpf_set_run_ctx(&run_ctx->run_ctx);
+
+ return bpf_prog_start_time();
+}
+
+void notrace __bpf_prog_exit_struct_ops(struct bpf_prog *prog, u64 start,
+ struct bpf_tramp_run_ctx *run_ctx)
+ __releases(RCU)
+{
+ bpf_reset_run_ctx(run_ctx->saved_run_ctx);
+
+ update_prog_stats(prog, start);
+ migrate_enable();
+ rcu_read_unlock();
+}
+
void notrace __bpf_tramp_enter(struct bpf_tramp_image *tr)
{
percpu_ref_get(&tr->pcref);
@@ -638,7 +1000,7 @@ void notrace __bpf_tramp_exit(struct bpf_tramp_image *tr)
int __weak
arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *image_end,
const struct btf_func_model *m, u32 flags,
- struct bpf_tramp_progs *tprogs,
+ struct bpf_tramp_links *tlinks,
void *orig_call)
{
return -ENOTSUPP;