netdev - [PATCH v3 bpf]: libbpf: fixing leak when kernel does not support btf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190308051814.19218-1-tehnerd@tehnerd.com>
Date:   Fri,  8 Mar 2019 05:18:14 +0000
From:   "Nikita V. Shirokov" <tehnerd@...nerd.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Yonghong Song <yhs@...com>
Cc:     netdev@...r.kernel.org, "Nikita V . Shirokov" <tehnerd@...nerd.com>
Subject: [PATCH v3 bpf]: libbpf: fixing leak when kernel does not support btf

we could end up in situation when we have object file w/ all btf
info but kernel does not support btf yet. in this situation currently
libbpf just set obj->btf to NULL w/o freeing it first.
this patch if fixing it by making sure to run btf__free first

v2->v3:
 - adding "Fixes" tag

v1->v2:
 - adding netdev to cc

Fixes: 8a138aed4a80 ("bpf: btf: Add BTF support to libbpf")
Signed-off-by: Nikita V. Shirokov <tehnerd@...nerd.com>
---
 tools/lib/bpf/libbpf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index f5eb60379c8d..d5b830d60601 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -838,6 +838,8 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
 			if (IS_ERR(obj->btf) || btf__load(obj->btf)) {
 				pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
 					   BTF_ELF_SEC, PTR_ERR(obj->btf));
+				if (!IS_ERR(obj->btf))
+					btf__free(obj->btf);
 				obj->btf = NULL;
 			}
 		} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
-- 
2.17.1