[PATCH 5.4 21/96] bpftool: Dont crash on missing xlated program instructions

[Greg Kroah-Hartman]

From: Toke HÃiland-JÃrgensen <toke@xxxxxxxxxx>

commit d95f1e8b462c4372ac409886070bb8719d8a4d3a upstream.

Turns out the xlated program instructions can also be missing if
kptr_restrict sysctl is set. This means that the previous fix to check the
jited_prog_insns pointer was insufficient; add another check of the
xlated_prog_insns pointer as well.

Fixes: 5b79bcdf0362 ("bpftool: Don't crash on missing jited insns or ksyms")
Fixes: cae73f233923 ("bpftool: use bpf_program__get_prog_info_linear() in prog.c:do_dump()")
Signed-off-by: Toke HÃiland-JÃrgensen <toke@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20200206102906.112551-1-toke@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 tools/bpf/bpftool/prog.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -500,7 +500,7 @@ static int do_dump(int argc, char **argv
 		buf = (unsigned char *)(info->jited_prog_insns);
 		member_len = info->jited_prog_len;
 	} else {	/* DUMP_XLATED */
-		if (info->xlated_prog_len == 0) {
+		if (info->xlated_prog_len == 0 || !info->xlated_prog_insns) {
 			p_err("error retrieving insn dump: kernel.kptr_restrict set?");
 			goto err_free;
 		}