bpf.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
	"Toke Høiland-Jørgensen" <toke@redhat.com>
Subject: [PATCH bpf v2] libbpf: don't crash on object files with no symbol tables
Date: Wed,  1 Sep 2021 13:48:12 +0200	[thread overview]
Message-ID: <20210901114812.204720-1-toke@redhat.com> (raw)

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.

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

Fixes: 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
 tools/lib/bpf/libbpf.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6f5e2757bb3c..997060182cef 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2990,6 +2990,12 @@ 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) {

             reply	other threads:[~2021-09-01 11:48 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-01 11:48 Toke Høiland-Jørgensen [this message]
2021-09-08  0:30 ` [PATCH bpf v2] libbpf: don't crash on object files with no symbol tables Andrii Nakryiko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210901114812.204720-1-toke@redhat.com \
    --to=toke@redhat.com \
    --cc=andrii@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=netdev@vger.kernel.org \


* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).