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From:   wuguanghao <wuguanghao3@huawei.com>
To:     <linux-ext4@vger.kernel.org>, <tytso@mit.edu>
CC:     <linfeilong@huawei.com>, <liuzhiqiang26@huawei.com>,
        <wuguanghao3@huawei.com>
Subject: [PATCH v3 10/12] hashmap: change return value type of ext2fs_hashmap_add()
Date:   Wed, 28 Jul 2021 09:56:47 +0800
Message-ID: <20210728015648.284588-4-wuguanghao3@huawei.com>
In-Reply-To: <20210728015648.284588-1-wuguanghao3@huawei.com>
References: <20210728015648.284588-1-wuguanghao3@huawei.com>
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From: Zhiqiang Liu <liuzhiqiang26@huawei.com>

In ext2fs_hashmap_add(), new entry is allocated by calling
malloc(). If malloc() return NULL, it will cause a
segmentation fault problem.

Here, we change return value type of ext2fs_hashmap_add()
from void to int. If allocating new entry fails, we will
return 1, and the callers should also verify the return
value of ext2fs_hashmap_add().

Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
---
 contrib/android/base_fs.c | 14 ++++++++++----
 lib/ext2fs/fileio.c       | 10 ++++++++--
 lib/ext2fs/hashmap.c      | 12 ++++++++++--
 lib/ext2fs/hashmap.h      |  5 +++--
 4 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/contrib/android/base_fs.c b/contrib/android/base_fs.c
index 652317e2..4ed44169 100644
--- a/contrib/android/base_fs.c
+++ b/contrib/android/base_fs.c
@@ -100,7 +100,7 @@ static void free_base_fs_entry(void *e)
 
 struct ext2fs_hashmap *basefs_parse(const char *file, const char *mountpoint)
 {
-	int err;
+	errcode_t err;
 	struct ext2fs_hashmap *entries = NULL;
 	struct basefs_entry *entry;
 	FILE *f = basefs_open(file);
@@ -110,10 +110,16 @@ struct ext2fs_hashmap *basefs_parse(const char *file, const char *mountpoint)
 	if (!entries)
 		goto end;
 
-	while ((entry = basefs_readline(f, mountpoint, &err)))
-		ext2fs_hashmap_add(entries, entry, entry->path,
+	while ((entry = basefs_readline(f, mountpoint, &err))) {
+		err = ext2fs_hashmap_add(entries, entry, entry->path,
 				   strlen(entry->path));
-
+		if (err) {
+			free_base_fs_entry(entry);
+			fclose(f);
+			ext2fs_hashmap_free(entries);
+			return NULL;
+		}
+	}
 	if (err) {
 		fclose(f);
 		ext2fs_hashmap_free(entries);
diff --git a/lib/ext2fs/fileio.c b/lib/ext2fs/fileio.c
index a0b5d971..2b0fb91e 100644
--- a/lib/ext2fs/fileio.c
+++ b/lib/ext2fs/fileio.c
@@ -475,8 +475,14 @@ errcode_t ext2fs_file_write(ext2_file_t file, const void *buf,
 
 			if (new_block) {
 				new_block->physblock = file->physblock;
-				ext2fs_hashmap_add(fs->block_sha_map, new_block,
-					new_block->sha, sizeof(new_block->sha));
+				errcode_t ret = ext2fs_hashmap_add(fs->block_sha_map,
+						new_block, new_block->sha,
+						sizeof(new_block->sha));
+				if (ret) {
+					retval = EXT2_ET_NO_MEMORY;
+					free(new_block);
+					goto fail;
+				}
 			}
 
 			if (bmap_flags & BMAP_SET) {
diff --git a/lib/ext2fs/hashmap.c b/lib/ext2fs/hashmap.c
index ffe61ce9..5239c921 100644
--- a/lib/ext2fs/hashmap.c
+++ b/lib/ext2fs/hashmap.c
@@ -36,6 +36,9 @@ struct ext2fs_hashmap *ext2fs_hashmap_create(
 {
 	struct ext2fs_hashmap *h = calloc(sizeof(struct ext2fs_hashmap) +
 				sizeof(struct ext2fs_hashmap_entry) * size, 1);
+	if (!h)
+		return NULL;
+
 	h->size = size;
 	h->free = free_fct;
 	h->hash = hash_fct;
@@ -43,12 +46,15 @@ struct ext2fs_hashmap *ext2fs_hashmap_create(
 	return h;
 }
 
-void ext2fs_hashmap_add(struct ext2fs_hashmap *h, void *data, const void *key,
-			size_t key_len)
+errcode_t ext2fs_hashmap_add(struct ext2fs_hashmap *h,
+		void *data, const void *key, size_t key_len)
 {
 	uint32_t hash = h->hash(key, key_len) % h->size;
 	struct ext2fs_hashmap_entry *e = malloc(sizeof(*e));
 
+	if (!e)
+		return -1;
+
 	e->data = data;
 	e->key = key;
 	e->key_len = key_len;
@@ -62,6 +68,8 @@ void ext2fs_hashmap_add(struct ext2fs_hashmap *h, void *data, const void *key,
 	h->first = e;
 	if (!h->last)
 		h->last = e;
+
+	return 0;
 }
 
 void *ext2fs_hashmap_lookup(struct ext2fs_hashmap *h, const void *key,
diff --git a/lib/ext2fs/hashmap.h b/lib/ext2fs/hashmap.h
index dcfa7455..43669a42 100644
--- a/lib/ext2fs/hashmap.h
+++ b/lib/ext2fs/hashmap.h
@@ -3,6 +3,7 @@
 
 # include <stdlib.h>
 # include <stdint.h>
+# include "et/com_err.h"
 
 #ifndef __GNUC_PREREQ
 #if defined(__GNUC__) && defined(__GNUC_MINOR__)
@@ -27,8 +28,8 @@ struct ext2fs_hashmap_entry {
 struct ext2fs_hashmap *ext2fs_hashmap_create(
 				uint32_t(*hash_fct)(const void*, size_t),
 				void(*free_fct)(void*), size_t size);
-void ext2fs_hashmap_add(struct ext2fs_hashmap *h, void *data, const void *key,
-			size_t key_len);
+errcode_t ext2fs_hashmap_add(struct ext2fs_hashmap *h,
+		       void *data, const void *key,size_t key_len);
 void *ext2fs_hashmap_lookup(struct ext2fs_hashmap *h, const void *key,
 			    size_t key_len);
 void *ext2fs_hashmap_iter_in_order(struct ext2fs_hashmap *h,
-- 
2.27.0