40 lines
1.3 KiB
Diff
40 lines
1.3 KiB
Diff
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From 3a3ef0c1d09e1894740db71cdcb7be0bfd713671 Mon Sep 17 00:00:00 2001
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From: Shung-Hsi Yu <shung-hsi.yu@suse.com>
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Date: Wed, 12 Oct 2022 10:23:53 +0800
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Subject: [PATCH 4/4] libbpf: Fix null-pointer dereference in
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find_prog_by_sec_insn()
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When there are no program sections, obj->programs is left unallocated,
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and find_prog_by_sec_insn()'s search lands on &obj->programs[0] == NULL,
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and will cause null-pointer dereference in the following access to
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prog->sec_idx.
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Guard the search with obj->nr_programs similar to what's being done in
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__bpf_program__iter() to prevent null-pointer access from happening.
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Fixes: db2b8b06423c ("libbpf: Support CO-RE relocations for multi-prog sections")
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Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
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Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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Link: https://lore.kernel.org/bpf/20221012022353.7350-4-shung-hsi.yu@suse.com
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---
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src/libbpf.c | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/src/libbpf.c b/src/libbpf.c
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index 29e9df0..8c3f236 100644
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--- a/src/libbpf.c
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+++ b/src/libbpf.c
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@@ -4115,6 +4115,9 @@ static struct bpf_program *find_prog_by_sec_insn(const struct bpf_object *obj,
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int l = 0, r = obj->nr_programs - 1, m;
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struct bpf_program *prog;
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+ if (!obj->nr_programs)
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+ return NULL;
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+
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while (l < r) {
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m = l + (r - l + 1) / 2;
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prog = &obj->programs[m];
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--
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2.38.0
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