linux-kernel - [PATCH 4.16 156/279] bpf, x64: fix memleak when not converging after image

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Message-Id: <20180618080615.286989869@linuxfoundation.org>
Date:   Mon, 18 Jun 2018 10:12:21 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.16 156/279] bpf, x64: fix memleak when not converging after image

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Daniel Borkmann <daniel@...earbox.net>

[ Upstream commit 3aab8884c9eb99189a3569ac4e6b205371c9ac0b ]

While reviewing x64 JIT code, I noticed that we leak the prior allocated
JIT image in the case where proglen != oldproglen during the JIT passes.
Prior to the commit e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT
compiler") we would just break out of the loop, and using the image as the
JITed prog since it could only shrink in size anyway. After e0ee9c12157d,
we would bail out to out_addrs label where we free addrs and jit_data but
not the image coming from bpf_jit_binary_alloc().

Fixes: e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler")
Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
Acked-by: Alexei Starovoitov <ast@...nel.org>
Acked-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/net/bpf_jit_comp.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1201,6 +1201,7 @@ skip_init_addrs:
 	for (pass = 0; pass < 20 || image; pass++) {
 		proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
 		if (proglen <= 0) {
+out_image:
 			image = NULL;
 			if (header)
 				bpf_jit_binary_free(header);
@@ -1211,8 +1212,7 @@ skip_init_addrs:
 			if (proglen != oldproglen) {
 				pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
 				       proglen, oldproglen);
-				prog = orig_prog;
-				goto out_addrs;
+				goto out_image;
 			}
 			break;
 		}