netdev - [PATCH net-next 3/7] ebpf: check first for MAXINSNS in bpf_prog

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <a1a9810494aebf0c0be8660e996b84c1cdb06444.1423610452.git.daniel@iogearbox.net>
Date:	Wed, 11 Feb 2015 01:15:14 +0100
From:	Daniel Borkmann <daniel@...earbox.net>
To:	jiri@...nulli.us
Cc:	ast@...mgrid.com, netdev@...r.kernel.org,
	Daniel Borkmann <daniel@...earbox.net>
Subject: [PATCH net-next 3/7] ebpf: check first for MAXINSNS in bpf_prog_load

Just minor ... before doing all the copying work, we may want
to check for instruction count earlier. Also, we may want to
warn the user in case we would otherwise need to truncate the
license information.

Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
---
 kernel/bpf/syscall.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 536edc2..73b105c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -473,25 +473,26 @@ static int bpf_prog_load(union bpf_attr *attr)
 {
 	enum bpf_prog_type type = attr->prog_type;
 	struct bpf_prog *prog;
-	int err;
 	char license[128];
 	bool is_gpl;
+	int err;
 
 	if (CHECK_ATTR(BPF_PROG_LOAD))
 		return -EINVAL;
+	if (attr->insn_cnt >= BPF_MAXINSNS)
+		return -EINVAL;
 
 	/* copy eBPF program license from user space */
-	if (strncpy_from_user(license, u64_to_ptr(attr->license),
-			      sizeof(license) - 1) < 0)
-		return -EFAULT;
-	license[sizeof(license) - 1] = 0;
+	err = strncpy_from_user(license, u64_to_ptr(attr->license),
+				sizeof(license));
+	if (err == sizeof(license))
+		err = -ERANGE;
+	if (err < 0)
+		return err;
 
 	/* eBPF programs must be GPL compatible to use GPL-ed functions */
 	is_gpl = license_is_gpl_compatible(license);
 
-	if (attr->insn_cnt >= BPF_MAXINSNS)
-		return -EINVAL;
-
 	/* plain bpf_prog allocation */
 	prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
 	if (!prog)
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html