Commit 03e601f4 authored by Toke Høiland-Jørgensen's avatar Toke Høiland-Jørgensen Committed by Andrii Nakryiko
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libbpf: Don't crash on object files with no symbol tables 



If libbpf encounters an ELF file that has been stripped of its symbol
table, it will crash in bpf_object__add_programs() when trying to
dereference the obj->efile.symbols pointer.

Fix this by erroring out of bpf_object__elf_collect() if it is not able
able to find the symbol table.

v2:
  - Move check into bpf_object__elf_collect() and add nice error message

Fixes: 6245947c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Signed-off-by: default avatarToke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210901114812.204720-1-toke@redhat.com
parent b238290b

tools/lib/bpf/libbpf.c

+6 −0
Original line number Diff line number Diff line
@@ -2993,6 +2993,12 @@ static int bpf_object__elf_collect(struct bpf_object *obj) 
		}

	}



	if (!obj->efile.symbols) {

		pr_warn("elf: couldn't find symbol table in %s, stripped object file?\n",

			obj->path);

		return -ENOENT;

	}



	scn = NULL;

	while ((scn = elf_nextscn(elf, scn)) != NULL) {

		idx++;