[PATCH] bpf: fix kmalloc bug in bpf_check

[Dongliang Mu]

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@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls")
Signed-off-by: Dongliang Mu <mudongliangabcd@xxxxxxxxx>
---
 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 ||
-- 
2.25.1