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authorYonghong Song <yhs@fb.com>2021-02-11 16:59:26 -0800
committerAlexei Starovoitov <ast@kernel.org>2021-02-12 13:33:50 -0800
commit17d8beda277a36203585943e70c7909b60775fd5 (patch)
tree34a79d7c80beb57fff98e0ea1077e2b06e0192e8 /kernel
parent90a82b1fa40d0cee33d1c9306dc54412442d1e57 (diff)
bpf: Fix an unitialized value in bpf_iter
Commit 15d83c4d7cef ("bpf: Allow loading of a bpf_iter program") cached btf_id in struct bpf_iter_target_info so later on if it can be checked cheaply compared to checking registered names. syzbot found a bug that uninitialized value may occur to bpf_iter_target_info->btf_id. This is because we allocated bpf_iter_target_info structure with kmalloc and never initialized field btf_id afterwards. This uninitialized btf_id is typically compared to a u32 bpf program func proto btf_id, and the chance of being equal is extremely slim. This patch fixed the issue by using kzalloc which will also prevent future likely instances due to adding new fields. Fixes: 15d83c4d7cef ("bpf: Allow loading of a bpf_iter program") Reported-by: syzbot+580f4f2a272e452d55cb@syzkaller.appspotmail.com Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210212005926.2875002-1-yhs@fb.com
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/bpf_iter.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 5454161407f1..a0d9eade9c80 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -287,7 +287,7 @@ int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info)
{
struct bpf_iter_target_info *tinfo;
- tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL);
+ tinfo = kzalloc(sizeof(*tinfo), GFP_KERNEL);
if (!tinfo)
return -ENOMEM;