bpftool: fix potential NULL pointer dereferencing in prog_dump()

A NULL pointer dereference could occur if ksyms
is not properly checked before usage in the prog_dump() function.

Fixes: b053b439b72a ("bpf: libbpf: bpftool: Print bpf_line_info during prog dump")
Signed-off-by: Amir Mohammadi <amiremohamadi@yahoo.com>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20241121083413.7214-1-amiremohamadi@yahoo.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 2ff949ea82fa66bcb993264902830601cabbd8b7..e71be67f1d86582e2224da7ba0030379f53110d8 100644 (file)
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -822,11 +822,18 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
                                        printf("%s:\n", sym_name);
                                }
 
-                               if (disasm_print_insn(img, lens[i], opcodes,
-                                                     name, disasm_opt, btf,
-                                                     prog_linfo, ksyms[i], i,
-                                                     linum))
-                                       goto exit_free;
+                               if (ksyms) {
+                                       if (disasm_print_insn(img, lens[i], opcodes,
+                                                             name, disasm_opt, btf,
+                                                             prog_linfo, ksyms[i], i,
+                                                             linum))
+                                               goto exit_free;
+                               } else {
+                                       if (disasm_print_insn(img, lens[i], opcodes,
+                                                             name, disasm_opt, btf,
+                                                             NULL, 0, 0, false))
+                                               goto exit_free;
+                               }
 
                                img += lens[i];