linux-kernel - [PATCH AUTOSEL 4.19 4/8] libsubcmd: Fix memory leak in uniq()

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Message-ID: <20240128161704.205756-4-sashal@kernel.org>
Date: Sun, 28 Jan 2024 11:16:55 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Chenyuan Mi <cymi20@...an.edu.cn>,
	Ingo Molnar <mingo@...hat.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.19 4/8] libsubcmd: Fix memory leak in uniq()

From: Ian Rogers <irogers@...gle.com>

[ Upstream commit ad30469a841b50dbb541df4d6971d891f703c297 ]

uniq() will write one command name over another causing the overwritten
string to be leaked. Fix by doing a pass that removes duplicates and a
second that removes the holes.

Signed-off-by: Ian Rogers <irogers@...gle.com>
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Chenyuan Mi <cymi20@...an.edu.cn>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Link: https://lore.kernel.org/r/20231208000515.1693746-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 tools/lib/subcmd/help.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/tools/lib/subcmd/help.c b/tools/lib/subcmd/help.c
index 2859f107abc8..4260c8b4257b 100644
--- a/tools/lib/subcmd/help.c
+++ b/tools/lib/subcmd/help.c
@@ -50,11 +50,21 @@ void uniq(struct cmdnames *cmds)
 	if (!cmds->cnt)
 		return;
 
-	for (i = j = 1; i < cmds->cnt; i++)
-		if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
-			cmds->names[j++] = cmds->names[i];
-
+	for (i = 1; i < cmds->cnt; i++) {
+		if (!strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
+			zfree(&cmds->names[i - 1]);
+	}
+	for (i = 0, j = 0; i < cmds->cnt; i++) {
+		if (cmds->names[i]) {
+			if (i == j)
+				j++;
+			else
+				cmds->names[j++] = cmds->names[i];
+		}
+	}
 	cmds->cnt = j;
+	while (j < i)
+		cmds->names[j++] = NULL;
 }
 
 void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
-- 
2.43.0