From: Alexei Starovoitov <ast@kernel.org>
To: "David S . Miller" <davem@davemloft.net>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
Jann Horn <jannh@google.com>, Edward Cree <ecree@solarflare.com>,
<netdev@vger.kernel.org>, <kernel-team@fb.com>
Subject: [PATCH bpf 5/9] bpf: fix missing error return in check_stack_boundary()
Date: Mon, 18 Dec 2017 20:11:57 -0800 [thread overview]
Message-ID: <20171219041201.1979983-6-ast@kernel.org> (raw)
In-Reply-To: <20171219041201.1979983-1-ast@kernel.org>
From: Jann Horn <jannh@google.com>
Prevent indirect stack accesses at non-constant addresses, which would
permit reading and corrupting spilled pointers.
Fixes: f1174f77b50c ("bpf/verifier: rework value tracking")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/bpf/verifier.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ecdc265244ca..77e4b5223867 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1303,6 +1303,7 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
tnum_strn(tn_buf, sizeof(tn_buf), regs[regno].var_off);
verbose(env, "invalid variable stack read R%d var_off=%s\n",
regno, tn_buf);
+ return -EACCES;
}
off = regs[regno].off + regs[regno].var_off.value;
if (off >= 0 || off < -MAX_BPF_STACK || off + access_size > 0 ||
--
2.9.5
next prev parent reply other threads:[~2017-12-19 4:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-19 4:11 [PATCH bpf 0/9] bpf: verifier security fixes Alexei Starovoitov
2017-12-19 4:11 ` [PATCH bpf 1/9] bpf/verifier: fix bounds calculation on BPF_RSH Alexei Starovoitov
2017-12-19 4:11 ` [PATCH bpf 2/9] bpf: fix incorrect sign extension in check_alu_op() Alexei Starovoitov
2017-12-19 4:11 ` [PATCH bpf 3/9] bpf: fix incorrect tracking of register size truncation Alexei Starovoitov
2017-12-19 4:11 ` [PATCH bpf 4/9] bpf: fix 32-bit ALU op verification Alexei Starovoitov
2017-12-19 4:11 ` Alexei Starovoitov [this message]
2017-12-19 4:11 ` [PATCH bpf 6/9] bpf: force strict alignment checks for stack pointers Alexei Starovoitov
2017-12-19 4:11 ` [PATCH bpf 7/9] bpf: don't prune branches when a scalar is replaced with a pointer Alexei Starovoitov
2017-12-19 4:12 ` [PATCH bpf 8/9] bpf: fix integer overflows Alexei Starovoitov
2017-12-19 10:29 ` Edward Cree
2017-12-19 19:57 ` Alexei Starovoitov
2017-12-19 4:12 ` [PATCH bpf 9/9] selftests/bpf: add tests for recent bugfixes Alexei Starovoitov
2017-12-21 2:20 ` [PATCH bpf 0/9] bpf: verifier security fixes Daniel Borkmann
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