[PATCH V2 10/12] hashmap: change return value type of, ext2fs_hashmap_add()

Wu Guanghao
2021-05-31T01:32:58Z

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 | 12 +++++++++---
lib/ext2fs/fileio.c | 10 ++++++++--
lib/ext2fs/hashmap.c | 12 ++++++++++--
lib/ext2fs/hashmap.h | 4 ++--
4 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/contrib/android/base_fs.c b/contrib/android/base_fs.c
index 652317e2..d3e00d18 100644
--- a/contrib/android/base_fs.c
+++ b/contrib/android/base_fs.c
@@ -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..818f7f05 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));
+ int 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..7278edaf 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)
+int 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..0c09d2bd 100644
--- a/lib/ext2fs/hashmap.h
+++ b/lib/ext2fs/hashmap.h
@@ -27,8 +27,8 @@ 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);
+int 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,
--