Re: [PATCH] bpf: fix kmalloc bug in bpf_check
From: Yonghong Song <hidden>
Date: 2021-09-13 15:35:45
Also in:
bpf, lkml
On 9/13/21 4:02 AM, Dongliang Mu wrote:
Since 7661809d493b ("mm: don't allow oversized kvmalloc() calls
") does not allow oversized kvmalloc, it triggers a kmalloc bug warning
at bpf_check.
Fix it by adding a sanity check in th check_btf_line.
Reported-by: syzbot+f3e749d4c662818ae439@syzkaller.appspotmail.com
Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls")
Signed-off-by: Dongliang Mu <redacted>Thanks for the fix. A similar patch has been proposed here: https://lore.kernel.org/bpf/20210911005557.45518-1-cuibixuan@huawei.com/ (local)
quoted hunk ↗ jump to hunk
--- kernel/bpf/verifier.c | 3 +++ 1 file changed, 3 insertions(+)diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 047ac4b4703b..3c5a79f78bc5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c@@ -9913,6 +9913,9 @@ static int check_btf_line(struct bpf_verifier_env *env, if (!nr_linfo) return 0; + if (nr_linfo > INT_MAX/sizeof(struct bpf_line_info)) + return -EINVAL; + rec_size = attr->line_info_rec_size; if (rec_size < MIN_BPF_LINEINFO_SIZE || rec_size > MAX_LINEINFO_REC_SIZE ||