hfs: make proper initalization of struct hfs_find_data

Potenatially, __hfs_ext_read_extent() could operate by
not initialized values of fd->key after hfs_brec_find() call:

static inline int __hfs_ext_read_extent(struct hfs_find_data *fd, struct hfs_extent *extent,
                                        u32 cnid, u32 block, u8 type)
{
        int res;

        hfs_ext_build_key(fd->search_key, cnid, block, type);
        fd->key->ext.FNum = 0;
        res = hfs_brec_find(fd);
        if (res && res != -ENOENT)
                return res;
        if (fd->key->ext.FNum != fd->search_key->ext.FNum ||
            fd->key->ext.FkType != fd->search_key->ext.FkType)
                return -ENOENT;
        if (fd->entrylength != sizeof(hfs_extent_rec))
                return -EIO;
        hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfs_extent_rec));
        return 0;
}

This patch changes kmalloc() on kzalloc() in hfs_find_init()
and intializes fd->record, fd->keyoffset, fd->keylength,
fd->entryoffset, fd->entrylength for the case if hfs_brec_find()
has been found nothing in the b-tree node.

Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20250818225252.126427-1-slava@dubeyko.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>

diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
index 34e9804e0f3601f54b27abe387458e16f32a6b4c..e46f650b5e9c26c983e9bdd18c79dd4271242e6c 100644 (file)
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -21,7 +21,7 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)
 
        fd->tree = tree;
        fd->bnode = NULL;
-       ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
+       ptr = kzalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
        if (!ptr)
                return -ENOMEM;
        fd->search_key = ptr;
@@ -115,6 +115,12 @@ int hfs_brec_find(struct hfs_find_data *fd)
        __be32 data;
        int height, res;
 
+       fd->record = -1;
+       fd->keyoffset = -1;
+       fd->keylength = -1;
+       fd->entryoffset = -1;
+       fd->entrylength = -1;
+
        tree = fd->tree;
        if (fd->bnode)
                hfs_bnode_put(fd->bnode);