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From: Alexei Starovoitov <ast@kernel.org>
To: <davem@davemloft.net>
Cc: <daniel@iogearbox.net>, <jolsa@redhat.com>,
	<netdev@vger.kernel.org>, <bpf@vger.kernel.org>,
	<kernel-team@fb.com>
Subject: [PATCH bpf-next] bpf: Fix bpf jit kallsym access
Date: Wed, 30 Oct 2019 16:30:19 -0700	[thread overview]
Message-ID: <20191030233019.1187404-1-ast@kernel.org> (raw)

Jiri reported crash when JIT is on, but net.core.bpf_jit_kallsyms is off.
bpf_prog_kallsyms_find() was skipping addr->bpf_prog resolution
logic in oops and stack traces. That's incorrect.
It should only skip addr->name resolution for 'cat /proc/kallsyms'.
That's what bpf_jit_kallsyms and bpf_jit_harden protect.

Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Fixes: 3dec541b2e63 ("bpf: Add support for BTF pointers to x86 JIT")
---
 kernel/bpf/core.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 673f5d40a93e..8d3fbc86ca5e 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -668,9 +668,6 @@ static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
 {
 	struct latch_tree_node *n;
 
-	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 :
-- 
2.17.1


             reply	other threads:[~2019-10-30 23:30 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-30 23:30 Alexei Starovoitov [this message]
2019-10-31  1:03 ` [PATCH bpf-next] bpf: Fix bpf jit kallsym access Daniel Borkmann
2019-10-31 10:22 ` Jiri Olsa

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