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authorDaniel Xu <dxu@dxuuu.xyz>2021-07-29 02:09:21 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2021-08-07 02:39:15 +0300
commitc34c338a40e4f3b6f80889cd17fd9281784d1c32 (patch)
tree332be058a454d94d772a7213578003e1b07cf776 /tools/lib/bpf/btf.c
parent78d14bda861dd2729f15bb438fe355b48514bfe0 (diff)
downloadlinux-c34c338a40e4f3b6f80889cd17fd9281784d1c32.tar.xz
libbpf: Do not close un-owned FD 0 on errors
Before this patch, btf_new() was liable to close an arbitrary FD 0 if BTF parsing failed. This was because: * btf->fd was initialized to 0 through the calloc() * btf__free() (in the `done` label) closed any FDs >= 0 * btf->fd is left at 0 if parsing fails This issue was discovered on a system using libbpf v0.3 (without BTF_KIND_FLOAT support) but with a kernel that had BTF_KIND_FLOAT types in BTF. Thus, parsing fails. While this patch technically doesn't fix any issues b/c upstream libbpf has BTF_KIND_FLOAT support, it'll help prevent issues in the future if more BTF types are added. It also allow the fix to be backported to older libbpf's. Fixes: 3289959b97ca ("libbpf: Support BTF loading and raw data output in both endianness") Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/5969bb991adedb03c6ae93e051fd2a00d293cf25.1627513670.git.dxu@dxuuu.xyz
Diffstat (limited to 'tools/lib/bpf/btf.c')
-rw-r--r--tools/lib/bpf/btf.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index b46760b93bb4..7ff3d5ce44f9 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -804,6 +804,7 @@ static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf)
btf->nr_types = 0;
btf->start_id = 1;
btf->start_str_off = 0;
+ btf->fd = -1;
if (base_btf) {
btf->base_btf = base_btf;
@@ -832,8 +833,6 @@ static struct btf *btf_new(const void *data, __u32 size, struct btf *base_btf)
if (err)
goto done;
- btf->fd = -1;
-
done:
if (err) {
btf__free(btf);