From 03dafb5f59bd31b3f590329e95434203f0ca6661 Mon Sep 17 00:00:00 2001
From: Chen Gang <gang.chen@asianux.com>
Date: Thu, 24 Jan 2013 23:24:58 -0500
Subject: [PATCH] ext4: fix memory leak when quota options are specified
 multiple times

When usrjquota or grpjquota mount options are specified several times,
we leak memory storing the names. Free the memory correctly.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/super.c | 52 +++++++++++++++++++++++++++----------------------
 1 file changed, 29 insertions(+), 23 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3ac306064b28..3b04d15f303d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1337,6 +1337,7 @@ static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	char *qname;
+	int ret = -1;
 
 	if (sb_any_quota_loaded(sb) &&
 		!sbi->s_qf_names[qtype]) {
@@ -1351,23 +1352,26 @@ static int set_qf_name(struct super_block *sb, int qtype, substring_t *args)
 			"Not enough memory for storing quotafile name");
 		return -1;
 	}
-	if (sbi->s_qf_names[qtype] &&
-		strcmp(sbi->s_qf_names[qtype], qname)) {
-		ext4_msg(sb, KERN_ERR,
-			"%s quota file already specified", QTYPE2NAME(qtype));
-		kfree(qname);
-		return -1;
+	if (sbi->s_qf_names[qtype]) {
+		if (strcmp(sbi->s_qf_names[qtype], qname) == 0)
+			ret = 1;
+		else
+			ext4_msg(sb, KERN_ERR,
+				 "%s quota file already specified",
+				 QTYPE2NAME(qtype));
+		goto errout;
 	}
-	sbi->s_qf_names[qtype] = qname;
-	if (strchr(sbi->s_qf_names[qtype], '/')) {
+	if (strchr(qname, '/')) {
 		ext4_msg(sb, KERN_ERR,
 			"quotafile must be on filesystem root");
-		kfree(sbi->s_qf_names[qtype]);
-		sbi->s_qf_names[qtype] = NULL;
-		return -1;
+		goto errout;
 	}
+	sbi->s_qf_names[qtype] = qname;
 	set_opt(sb, QUOTA);
 	return 1;
+errout:
+	kfree(qname);
+	return ret;
 }
 
 static int clear_qf_name(struct super_block *sb, int qtype)
@@ -1381,10 +1385,7 @@ static int clear_qf_name(struct super_block *sb, int qtype)
 			" when quota turned on");
 		return -1;
 	}
-	/*
-	 * The space will be released later when all options are confirmed
-	 * to be correct
-	 */
+	kfree(sbi->s_qf_names[qtype]);
 	sbi->s_qf_names[qtype] = NULL;
 	return 1;
 }
@@ -4593,7 +4594,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
 	int err = 0;
 #ifdef CONFIG_QUOTA
-	int i;
+	int i, j;
 #endif
 	char *orig_data = kstrdup(data, GFP_KERNEL);
 
@@ -4609,7 +4610,16 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 #ifdef CONFIG_QUOTA
 	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
 	for (i = 0; i < MAXQUOTAS; i++)
-		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
+		if (sbi->s_qf_names[i]) {
+			old_opts.s_qf_names[i] = kstrdup(sbi->s_qf_names[i],
+							 GFP_KERNEL);
+			if (!old_opts.s_qf_names[i]) {
+				for (j = 0; j < i; j++)
+					kfree(old_opts.s_qf_names[j]);
+				return -ENOMEM;
+			}
+		} else
+			old_opts.s_qf_names[i] = NULL;
 #endif
 	if (sbi->s_journal && sbi->s_journal->j_task->io_context)
 		journal_ioprio = sbi->s_journal->j_task->io_context->ioprio;
@@ -4742,9 +4752,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 #ifdef CONFIG_QUOTA
 	/* Release old quota file names */
 	for (i = 0; i < MAXQUOTAS; i++)
-		if (old_opts.s_qf_names[i] &&
-		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
-			kfree(old_opts.s_qf_names[i]);
+		kfree(old_opts.s_qf_names[i]);
 	if (enable_quota) {
 		if (sb_any_quota_suspended(sb))
 			dquot_resume(sb, -1);
@@ -4773,9 +4781,7 @@ restore_opts:
 #ifdef CONFIG_QUOTA
 	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
 	for (i = 0; i < MAXQUOTAS; i++) {
-		if (sbi->s_qf_names[i] &&
-		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
-			kfree(sbi->s_qf_names[i]);
+		kfree(sbi->s_qf_names[i]);
 		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
 	}
 #endif
-- 
2.20.1