Commit dde7011a authored Nov 21, 2018 by Jakub Kicinski Committed by Daniel Borkmann Nov 22, 2018

tools: bpftool: fix potential NULL pointer dereference in do_load



This patch fixes a possible null pointer dereference in
do_load, detected by the semantic patch deref_null.cocci,
with the following warning:

./tools/bpf/bpftool/prog.c:1021:23-25: ERROR: map_replace is NULL but dereferenced.

The following code has potential null pointer references:
881             map_replace = reallocarray(map_replace, old_map_fds + 1,
882                                        sizeof(*map_replace));
883             if (!map_replace) {
884                     p_err("mem alloc failed");
885                     goto err_free_reuse_maps;
886             }

...
1019 err_free_reuse_maps:
1020         for (i = 0; i < old_map_fds; i++)
1021                 close(map_replace[i].fd);
1022         free(map_replace);

Fixes: 3ff5a4dc ("tools: bpftool: allow reuse of maps with bpftool prog load")
Co-developed-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 569a933b

tools/bpf/bpftool/prog.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -844,6 +844,7 @@ static int do_load(int argc, char **argv)
		}
		NEXT_ARG();
		} else if (is_prefix(*argv, "map")) {
		void *new_map_replace;
		char endptr, name;
		int fd;

		@@ -877,12 +878,15 @@ static int do_load(int argc, char **argv)
		if (fd < 0)
		goto err_free_reuse_maps;

		map_replace = reallocarray(map_replace, old_map_fds + 1,
		new_map_replace = reallocarray(map_replace,
		old_map_fds + 1,
		sizeof(*map_replace));
		if (!map_replace) {
		if (!new_map_replace) {
		p_err("mem alloc failed");
		goto err_free_reuse_maps;
		}
		map_replace = new_map_replace;

		map_replace[old_map_fds].idx = idx;
		map_replace[old_map_fds].name = name;
		map_replace[old_map_fds].fd = fd;

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