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From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
	<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
	Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH bpf-next 1/5] libbpf: fix memory leak/double free issue
Date: Wed, 6 Nov 2019 18:08:51 -0800	[thread overview]
Message-ID: <20191107020855.3834758-2-andriin@fb.com> (raw)
In-Reply-To: <20191107020855.3834758-1-andriin@fb.com>

Coverity scan against Github libbpf code found the issue of not freeing memory and
leaving already freed memory still referenced from bpf_program. Fix it by
re-assigning successfully reallocated memory sooner.

Fixes: 2993e0515bb4 ("tools/bpf: add support to read .BTF.ext sections")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/lib/bpf/libbpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index be4af95d5a2c..3ef73a214592 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3523,6 +3523,7 @@ bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
 			pr_warn("oom in prog realloc\n");
 			return -ENOMEM;
 		}
+		prog->insns = new_insn;
 
 		if (obj->btf_ext) {
 			err = bpf_program_reloc_btf_ext(prog, obj,
@@ -3534,7 +3535,6 @@ bpf_program__reloc_text(struct bpf_program *prog, struct bpf_object *obj,
 
 		memcpy(new_insn + prog->insns_cnt, text->insns,
 		       text->insns_cnt * sizeof(*insn));
-		prog->insns = new_insn;
 		prog->main_prog_cnt = prog->insns_cnt;
 		prog->insns_cnt = new_cnt;
 		pr_debug("added %zd insn from %s to prog %s\n",
-- 
2.17.1


  reply	other threads:[~2019-11-07  2:09 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-07  2:08 [PATCH bpf-next 0/5] Fix bugs and issues found by static analysis in libbpf Andrii Nakryiko
2019-11-07  2:08 ` Andrii Nakryiko [this message]
2019-11-07  2:08 ` [PATCH bpf-next 2/5] libbpf: fix potential overflow issue Andrii Nakryiko
2019-11-07  2:08 ` [PATCH bpf-next 3/5] libbpf: fix another potential overflow issue in bpf_prog_linfo Andrii Nakryiko
2019-11-07  2:08 ` [PATCH bpf-next 4/5] libbpf: make btf__resolve_size logic always check size error condition Andrii Nakryiko
2019-11-07  2:08 ` [PATCH bpf-next 5/5] libbpf: improve handling of corrupted ELF during map initialization Andrii Nakryiko
2019-11-07 16:35 ` [PATCH bpf-next 0/5] Fix bugs and issues found by static analysis in libbpf Daniel Borkmann

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