From aa3ac52204f801e5215e79dc94167cbe9c89106e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>
Date: Tue, 10 Dec 2019 19:14:12 +0100
Subject: [PATCH] bpftool: Don't crash on missing jited insns or ksyms
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commit 5b79bcdf03628a3a9ee04d9cd5fabcf61a8e20be upstream.

When the kptr_restrict sysctl is set, the kernel can fail to return
jited_ksyms or jited_prog_insns, but still have positive values in
nr_jited_ksyms and jited_prog_len. This causes bpftool to crash when
trying to dump the program because it only checks the len fields not
the actual pointers to the instructions and ksyms.

Fix this by adding the missing checks.

Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
Fixes: f84192ee00b7 ("tools: bpftool: resolve calls without using imm field")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191210181412.151226-1-toke@redhat.com
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index d41651afe5f6..2971499c45df 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -492,7 +492,7 @@ static int do_dump(int argc, char **argv)
 
 	info = &info_linear->info;
 	if (mode == DUMP_JITED) {
-		if (info->jited_prog_len == 0) {
+		if (info->jited_prog_len == 0 || !info->jited_prog_insns) {
 			p_info("no instructions returned");
 			goto err_free;
 		}
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 0bb17bf88b18..0ad5fe6b432b 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -176,7 +176,7 @@ static const char *print_call(void *private_data,
 	struct kernel_sym *sym;
 
 	if (insn->src_reg == BPF_PSEUDO_CALL &&
-	    (__u32) insn->imm < dd->nr_jited_ksyms)
+	    (__u32) insn->imm < dd->nr_jited_ksyms && dd->jited_ksyms)
 		address = dd->jited_ksyms[insn->imm];
 
 	sym = kernel_syms_search(dd, address);
-- 
2.7.4