netdev - [PATCH bpf-next 1/9] libbpf: fix detection of corrupted BPF instructions section

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: <20190529011426.1328736-2-andriin@fb.com>
Date:   Tue, 28 May 2019 18:14:18 -0700
From:   Andrii Nakryiko <andriin@...com>
To:     <andrii.nakryiko@...il.com>, <netdev@...r.kernel.org>,
        <bpf@...r.kernel.org>, <ast@...com>, <daniel@...earbox.net>,
        <kernel-team@...com>
CC:     Andrii Nakryiko <andriin@...com>
Subject: [PATCH bpf-next 1/9] libbpf: fix detection of corrupted BPF instructions section

Ensure that size of a section w/ BPF instruction is exactly a multiple
of BPF instruction size.

Signed-off-by: Andrii Nakryiko <andriin@...com>
---
 tools/lib/bpf/libbpf.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ca4432f5b067..05a73223e524 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -349,8 +349,11 @@ static int
 bpf_program__init(void *data, size_t size, char *section_name, int idx,
 		  struct bpf_program *prog)
 {
-	if (size < sizeof(struct bpf_insn)) {
-		pr_warning("corrupted section '%s'\n", section_name);
+	const size_t bpf_insn_sz = sizeof(struct bpf_insn);
+
+	if (size < bpf_insn_sz || size % bpf_insn_sz) {
+		pr_warning("corrupted section '%s', size: %zu\n",
+			   section_name, size);
 		return -EINVAL;
 	}
 
@@ -376,9 +379,8 @@ bpf_program__init(void *data, size_t size, char *section_name, int idx,
 			   section_name);
 		goto errout;
 	}
-	prog->insns_cnt = size / sizeof(struct bpf_insn);
-	memcpy(prog->insns, data,
-	       prog->insns_cnt * sizeof(struct bpf_insn));
+	prog->insns_cnt = size / bpf_insn_sz;
+	memcpy(prog->insns, data, prog->insns_cnt * bpf_insn_sz);
 	prog->idx = idx;
 	prog->instances.fds = NULL;
 	prog->instances.nr = -1;
-- 
2.17.1