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From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
	<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
	Andrii Nakryiko <andriin@fb.com>
Subject: [PATCH bpf-next 3/4] libbpf: fix potential multiplication overflow in mmap() size calculation
Date: Thu, 16 Jan 2020 22:08:00 -0800	[thread overview]
Message-ID: <20200117060801.1311525-4-andriin@fb.com> (raw)
In-Reply-To: <20200117060801.1311525-1-andriin@fb.com>

Prevent potential overflow performed in 32-bit integers, before assigning
result to size_t. Reported by LGTM static analysis.

Fixes: eba9c5f498a1 ("libbpf: Refactor global data map initialization")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
 tools/lib/bpf/libbpf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 3b0b88c3377d..fc41c3f2e983 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1283,7 +1283,7 @@ static size_t bpf_map_mmap_sz(const struct bpf_map *map)
 	long page_sz = sysconf(_SC_PAGE_SIZE);
 	size_t map_sz;
 
-	map_sz = roundup(map->def.value_size, 8) * map->def.max_entries;
+	map_sz = (size_t)roundup(map->def.value_size, 8) * map->def.max_entries;
 	map_sz = roundup(map_sz, page_sz);
 	return map_sz;
 }
-- 
2.17.1


  parent reply	other threads:[~2020-01-17  6:08 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-17  6:07 [PATCH bpf-next 0/4] Fix few unrelated small bugs and issues Andrii Nakryiko
2020-01-17  6:07 ` [PATCH bpf-next 1/4] libbpf: fix error handling bug in btf_dump__new Andrii Nakryiko
2020-01-17  6:07 ` [PATCH bpf-next 2/4] libbpf: simplify BTF initialization logic Andrii Nakryiko
2020-01-17  6:08 ` Andrii Nakryiko [this message]
2020-01-17  6:08 ` [PATCH bpf-next 4/4] bpftool: avoid const discard compilation warning Andrii Nakryiko
2020-01-17 15:55   ` Quentin Monnet
2020-01-17 19:03     ` Andrii Nakryiko
2020-01-17 16:35 ` [PATCH bpf-next 0/4] Fix few unrelated small bugs and issues Alexei Starovoitov

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