From 5b79bcdf03628a3a9ee04d9cd5fabcf61a8e20be Mon Sep 17 00:00:00 2001 From: Toke Høiland-Jørgensen Date: Tue, 10 Dec 2019 19:14:12 +0100 Subject: bpftool: Don't crash on missing jited insns or ksyms MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Link: https://lore.kernel.org/bpf/20191210181412.151226-1-toke@redhat.com --- tools/bpf/bpftool/prog.c | 2 +- tools/bpf/bpftool/xlated_dumper.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'tools') diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 4535c863d2cd..2ce9c5ba1934 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -493,7 +493,7 @@ 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 494d7ae3614d..5b91ee65a080 100644 --- a/tools/bpf/bpftool/xlated_dumper.c +++ b/tools/bpf/bpftool/xlated_dumper.c @@ -174,7 +174,7 @@ 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); -- cgit v1.2.3-59-g8ed1b