Commit af91acbc authored Oct 30, 2019 by Alexei Starovoitov Committed by Daniel Borkmann Oct 31, 2019

bpf: Fix bpf jit kallsym access



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.

Fixes: 3dec541b ("bpf: Add support for BTF pointers to x86 JIT")
Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191030233019.1187404-1-ast@kernel.org

parent cf204a71

kernel/bpf/core.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -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 :

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