[PATCH] bpf: Use safer kvmalloc_array() where possible

From: Dan Carpenter <dan.carpenter@oracle.com>
To: Steven Rostedt <rostedt@goodmis.org>, Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	bpf@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] bpf: Use safer kvmalloc_array() where possible
Date: Thu, 26 May 2022 13:24:05 +0300	[thread overview]
Message-ID: <Yo9VRVMeHbALyjUH@kili> (raw)

The kvmalloc_array() function is safer because it has a check for
integer overflows.  These sizes come from the user and I was not
able to see any bounds checking so an integer overflow seems like a
realistic concern.

Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 kernel/trace/bpf_trace.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 10b157a6d73e..7a13e6ac6327 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2263,11 +2263,11 @@ static int copy_user_syms(struct user_syms *us, unsigned long __user *usyms, u32
 	int err = -ENOMEM;
 	unsigned int i;
 
-	syms = kvmalloc(cnt * sizeof(*syms), GFP_KERNEL);
+	syms = kvmalloc_array(cnt, sizeof(*syms), GFP_KERNEL);
 	if (!syms)
 		goto error;
 
-	buf = kvmalloc(cnt * KSYM_NAME_LEN, GFP_KERNEL);
+	buf = kvmalloc_array(cnt, KSYM_NAME_LEN, GFP_KERNEL);
 	if (!buf)
 		goto error;
 
@@ -2464,7 +2464,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 		return -EINVAL;
 
 	size = cnt * sizeof(*addrs);
-	addrs = kvmalloc(size, GFP_KERNEL);
+	addrs = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
 	if (!addrs)
 		return -ENOMEM;
 
@@ -2489,7 +2489,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
 
 	ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies);
 	if (ucookies) {
-		cookies = kvmalloc(size, GFP_KERNEL);
+		cookies = kvmalloc_array(cnt, sizeof(*addrs), GFP_KERNEL);
 		if (!cookies) {
 			err = -ENOMEM;
 			goto error;
-- 
2.35.1

