We later want to give users a quick dump of what is possible with procfs, so store a list of all currently loaded bpf programs. Later this list will be printed in procfs.
Signed-off-by: Hannes Frederic Sowa <han...@stressinduktion.org> --- include/linux/filter.h | 4 ++-- kernel/bpf/core.c | 51 +++++++++++++++++++++++--------------------------- kernel/bpf/syscall.c | 4 ++-- 3 files changed, 27 insertions(+), 32 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index 9a7786db14fa53..63624c619e371b 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -753,8 +753,8 @@ bpf_address_lookup(unsigned long addr, unsigned long *size, return ret; } -void bpf_prog_kallsyms_add(struct bpf_prog *fp); -void bpf_prog_kallsyms_del(struct bpf_prog *fp); +void bpf_prog_link(struct bpf_prog *fp); +void bpf_prog_unlink(struct bpf_prog *fp); #else /* CONFIG_BPF_JIT */ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 043f634ff58d87..2139118258cdf8 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -365,22 +365,6 @@ static struct latch_tree_root bpf_tree __cacheline_aligned; int bpf_jit_kallsyms __read_mostly; -static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux) -{ - WARN_ON_ONCE(!list_empty(&aux->bpf_progs_head)); - list_add_tail_rcu(&aux->bpf_progs_head, &bpf_progs); - latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); -} - -static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux) -{ - if (list_empty(&aux->bpf_progs_head)) - return; - - latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); - list_del_rcu(&aux->bpf_progs_head); -} - static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) { return fp->jited && !bpf_prog_was_classic(fp); @@ -392,38 +376,45 @@ static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) fp->aux->bpf_progs_head.prev == LIST_POISON2; } -void bpf_prog_kallsyms_add(struct bpf_prog *fp) +void bpf_prog_link(struct bpf_prog *fp) { - if (!bpf_prog_kallsyms_candidate(fp) || - !capable(CAP_SYS_ADMIN)) - return; + struct bpf_prog_aux *aux = fp->aux; spin_lock_bh(&bpf_lock); - bpf_prog_ksym_node_add(fp->aux); + list_add_tail_rcu(&aux->bpf_progs_head, &bpf_progs); + if (bpf_prog_kallsyms_candidate(fp)) + latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); spin_unlock_bh(&bpf_lock); } -void bpf_prog_kallsyms_del(struct bpf_prog *fp) +void bpf_prog_unlink(struct bpf_prog *fp) { - if (!bpf_prog_kallsyms_candidate(fp)) - return; + struct bpf_prog_aux *aux = fp->aux; spin_lock_bh(&bpf_lock); - bpf_prog_ksym_node_del(fp->aux); + list_del_rcu(&aux->bpf_progs_head); + if (bpf_prog_kallsyms_candidate(fp)) + latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); spin_unlock_bh(&bpf_lock); } static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) { struct latch_tree_node *n; + struct bpf_prog *prog; if (!bpf_jit_kallsyms_enabled()) return NULL; n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); - return n ? - container_of(n, struct bpf_prog_aux, ksym_tnode)->prog : - NULL; + if (!n) + return NULL; + + prog = container_of(n, struct bpf_prog_aux, ksym_tnode)->prog; + if (!prog->priv_cap_sys_admin) + return NULL; + + return prog; } const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, @@ -474,6 +465,10 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, rcu_read_lock(); list_for_each_entry_rcu(aux, &bpf_progs, bpf_progs_head) { + if (!bpf_prog_kallsyms_candidate(aux->prog) || + !aux->prog->priv_cap_sys_admin) + continue; + if (it++ != symnum) continue; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 13642c73dca0b4..d61d1bd3e6fee6 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -664,7 +664,7 @@ void bpf_prog_put(struct bpf_prog *prog) { if (atomic_dec_and_test(&prog->aux->refcnt)) { trace_bpf_prog_put_rcu(prog); - bpf_prog_kallsyms_del(prog); + bpf_prog_unlink(prog); call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu); } } @@ -858,7 +858,7 @@ static int bpf_prog_load(union bpf_attr *attr) /* failed to allocate fd */ goto free_used_maps; - bpf_prog_kallsyms_add(prog); + bpf_prog_link(prog); trace_bpf_prog_load(prog, err); return err; -- 2.9.3