On 2 Feb 2020, at 17:53, Trond Myklebust wrote:
nfs_readdir_xdr_to_array() must not exit without having initialised
the array, so that the page cache deletion routines can safely
call nfs_readdir_clear_array().
Furthermore, we should ensure that if we exit nfs_readdir_filler()
with an error, we free up any page contents to prevent a leak
if we try to fill the page again.
Fixes: 11de3b11e08c ("NFS: Fix a memory leak in nfs_readdir")
Cc: stable@xxxxxxxxxxxxxxx # v2.6.37+
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Looks good to me.
Reviewed-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
Ben
---
fs/nfs/dir.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 76404f53cf21..ba0d55930e8a 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -163,6 +163,17 @@ typedef struct {
bool eof;
} nfs_readdir_descriptor_t;
+static
+void nfs_readdir_init_array(struct page *page)
+{
+ struct nfs_cache_array *array;
+
+ array = kmap_atomic(page);
+ memset(array, 0, sizeof(struct nfs_cache_array));
+ array->eof_index = -1;
+ kunmap_atomic(array);
+}
+
/*
* we are freeing strings created by nfs_add_to_readdir_array()
*/
@@ -175,6 +186,7 @@ void nfs_readdir_clear_array(struct page *page)
array = kmap_atomic(page);
for (i = 0; i < array->size; i++)
kfree(array->array[i].string.name);
+ array->size = 0;
kunmap_atomic(array);
}
@@ -613,6 +625,8 @@ int
nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page
*page,
int status = -ENOMEM;
unsigned int array_size = ARRAY_SIZE(pages);
+ nfs_readdir_init_array(page);
+
entry.prev_cookie = 0;
entry.cookie = desc->last_cookie;
entry.eof = 0;
@@ -629,8 +643,6 @@ int
nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page
*page,
}
array = kmap(page);
- memset(array, 0, sizeof(struct nfs_cache_array));
- array->eof_index = -1;
status = nfs_readdir_alloc_pages(pages, array_size);
if (status < 0)
@@ -685,6 +697,7 @@ int nfs_readdir_filler(void *data, struct page*
page)
unlock_page(page);
return 0;
error:
+ nfs_readdir_clear_array(page);
unlock_page(page);
return ret;
}
--
2.24.1
