[PATCH 1/4] perf libbfd: Validate BPF prog info arrays before pointer cast

[Arnaldo Carvalho de Melo <acme@kernel.org>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

symbol__disassemble_bpf_libbfd() casts info_linear->info.jited_prog_insns
and info_linear->info.jited_ksyms to pointers without checking whether
bpil_offs_to_addr() actually converted the file offsets.  A crafted
perf.data with PERF_BPIL_* bits unset but non-zero counts causes raw
file offsets to be dereferenced as pointers.

Add bitmask checks for PERF_BPIL_JITED_INSNS and PERF_BPIL_JITED_KSYMS
before the casts, matching the validation added to bpf-event.c call
sites.

Fixes: 6987561c9e86 ("perf annotate: Enable annotation of BPF programs")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/libbfd.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/perf/util/libbfd.c b/tools/perf/util/libbfd.c
index d8241c7caac50836..0b7164f0e9fdbbed 100644
--- a/tools/perf/util/libbfd.c
+++ b/tools/perf/util/libbfd.c
@@ -552,6 +552,11 @@ int symbol__disassemble_bpf_libbfd(struct symbol *sym __maybe_unused,
 	info_linear = info_node->info_linear;
 	sub_id = dso__bpf_prog(dso)->sub_id;
 
+	/* jited_prog_insns is only valid if bpil_offs_to_addr() converted it */
+	if (!(info_linear->arrays & (1UL << PERF_BPIL_JITED_INSNS))) {
+		ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
+		goto out;
+	}
 	info.buffer = (void *)(uintptr_t)(info_linear->info.jited_prog_insns);
 	info.buffer_length = info_linear->info.jited_prog_len;
 
@@ -581,6 +586,12 @@ int symbol__disassemble_bpf_libbfd(struct symbol *sym __maybe_unused,
 	if (disassemble == NULL)
 		abort();
 
+	/* jited_ksyms is only valid if bpil_offs_to_addr() converted it */
+	if (!(info_linear->arrays & (1UL << PERF_BPIL_JITED_KSYMS))) {
+		ret = SYMBOL_ANNOTATE_ERRNO__BPF_MISSING_BTF;
+		goto out;
+	}
+
 	fflush(s);
 	do {
 		const struct bpf_line_info *linfo = NULL;
-- 
2.55.0