The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4b310319c6a8ce708f1033d57145e2aa027a883c Mon Sep 17 00:00:00 2001
From: Trond Myklebust trondmy@gmail.com Date: Sun, 2 Feb 2020 17:53:53 -0500 Subject: [PATCH] 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: 11de3b11e08c ("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
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 6427a8a8d61a..451c48cdb1c2 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -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; }