From 5c3320d7fece4612d4a413aa3c8e82cdb5b49fcb Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 9 Jul 2020 18:10:23 -0700 Subject: [PATCH] libbpf: Fix memory leak and optimize BTF sanitization Coverity's static analysis helpfully reported a memory leak introduced by 0f0e55d8247c ("libbpf: Improve BTF sanitization handling"). While fixing it, I realized that btf__new() already creates a memory copy, so there is no need to do this. So this patch also fixes misleading btf__new() signature to make data into a `const void *` input parameter. And it avoids unnecessary memory allocation and copy in BTF sanitization code altogether. Fixes: 0f0e55d8247c ("libbpf: Improve BTF sanitization handling") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20200710011023.1655008-1-andriin@fb.com --- tools/lib/bpf/btf.c | 2 +- tools/lib/bpf/btf.h | 2 +- tools/lib/bpf/libbpf.c | 11 +++-------- 3 files changed, 5 insertions(+), 10 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index c8861c9e3635..c9e760e120dc 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -397,7 +397,7 @@ void btf__free(struct btf *btf) free(btf); } -struct btf *btf__new(__u8 *data, __u32 size) +struct btf *btf__new(const void *data, __u32 size) { struct btf *btf; int err; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 173eff23c472..a3b7ef9b737f 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -63,7 +63,7 @@ struct btf_ext_header { }; LIBBPF_API void btf__free(struct btf *btf); -LIBBPF_API struct btf *btf__new(__u8 *data, __u32 size); +LIBBPF_API struct btf *btf__new(const void *data, __u32 size); LIBBPF_API struct btf *btf__parse_elf(const char *path, struct btf_ext **btf_ext); LIBBPF_API int btf__finalize_data(struct bpf_object *obj, struct btf *btf); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 6602eb479596..25e4f77be8d7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2533,17 +2533,12 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) sanitize = btf_needs_sanitization(obj); if (sanitize) { - const void *orig_data; - void *san_data; + const void *raw_data; __u32 sz; /* clone BTF to sanitize a copy and leave the original intact */ - orig_data = btf__get_raw_data(obj->btf, &sz); - san_data = malloc(sz); - if (!san_data) - return -ENOMEM; - memcpy(san_data, orig_data, sz); - kern_btf = btf__new(san_data, sz); + raw_data = btf__get_raw_data(obj->btf, &sz); + kern_btf = btf__new(raw_data, sz); if (IS_ERR(kern_btf)) return PTR_ERR(kern_btf); -- 2.11.0