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NFS: Fix memory leaks and corruption in readdir 

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: 11de3b11e0 ("NFS: Fix a memory leak in nfs_readdir")
Cc: stable@vger.kernel.org # v2.6.37+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Trond Myklebust 2020-02-02 17:53:53 -05:00 committed by Anna Schumaker
parent 7ccbddbe3e
commit 4b310319c6
1 changed files with 15 additions and 2 deletions
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17
fs/nfs/dir.c
View File

@ -162,6 +162,17 @@ 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()
*/
@ -174,6 +185,7 @@ 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);
}
@ -610,6 +622,8 @@ 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;
@ -626,8 +640,6 @@ 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)
@ -682,6 +694,7 @@ 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;
}