netdev - [PATCH bpf-next 2/2] libbpf: fix potential multiplication overflow

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Date:   Thu, 3 Sep 2020 21:16:11 -0700
From:   Andrii Nakryiko <andriin@...com>
To:     <bpf@...r.kernel.org>, <netdev@...r.kernel.org>, <ast@...com>,
        <daniel@...earbox.net>
CC:     <andrii.nakryiko@...il.com>, <kernel-team@...com>,
        Andrii Nakryiko <andriin@...com>
Subject: [PATCH bpf-next 2/2] libbpf: fix potential multiplication overflow

Detected by LGTM static analyze in Github repo, fix potential multiplication
overflow before result is casted to size_t.

Fixes: 8505e8709b5e ("libbpf: Implement generalized .BTF.ext func/line info adjustment")
Signed-off-by: Andrii Nakryiko <andriin@...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 53be32a2b9fc..550950eb1860 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5802,7 +5802,7 @@ static int adjust_prog_btf_ext_info(const struct bpf_object *obj,
 		/* append func/line info of a given (sub-)program to the main
 		 * program func/line info
 		 */
-		old_sz = (*prog_rec_cnt) * ext_info->rec_size;
+		old_sz = (size_t)(*prog_rec_cnt) * ext_info->rec_size;
 		new_sz = old_sz + (copy_end - copy_start);
 		new_prog_info = realloc(*prog_info, new_sz);
 		if (!new_prog_info)
-- 
2.24.1