linux-kernel - [PATCH v1 1/3] lib subcmd: Fix memory leak in uniq

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Message-Id: <20231208000515.1693746-1-irogers@google.com>
Date:   Thu,  7 Dec 2023 16:05:13 -0800
From:   Ian Rogers <irogers@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Chenyuan Mi <cymi20@...an.edu.cn>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org
Subject: [PATCH v1 1/3] lib subcmd: Fix memory leak in uniq

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>
---
 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 adfbae27dc36..8561b0f01a24 100644
--- a/tools/lib/subcmd/help.c
+++ b/tools/lib/subcmd/help.c
@@ -52,11 +52,21 @@ 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)
-- 
2.43.0.472.g3155946c3a-goog