staging: erofs: fix to handle error path of erofs_vmap()

erofs_vmap() wrapped vmap() and vm_map_ram() to return virtual
continuous memory, but both of them can failed due to a lot of
reason, previously, erofs_vmap()'s callers didn't handle them,
which can potentially cause NULL pointer access, fix it.

Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
Fixes: 0d40d6e399c1 ("staging: erofs: add a generic z_erofs VLE decompressor")
Cc: <stable@vger.kernel.org> # 4.19+
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/erofs/unzip_vle.c b/drivers/staging/erofs/unzip_vle.c
index 8715bc5..c7b3b21 100644 (file)
--- a/drivers/staging/erofs/unzip_vle.c
+++ b/drivers/staging/erofs/unzip_vle.c
@@ -1029,6 +1029,10 @@ repeat:
 
 skip_allocpage:
        vout = erofs_vmap(pages, nr_pages);
+       if (!vout) {
+               err = -ENOMEM;
+               goto out;
+       }
 
        err = z_erofs_vle_unzip_vmap(compressed_pages,
                clusterpages, vout, llen, work->pageofs, overlapped);

diff --git a/drivers/staging/erofs/unzip_vle_lz4.c b/drivers/staging/erofs/unzip_vle_lz4.c
index 48b263a..0daac9b 100644 (file)
--- a/drivers/staging/erofs/unzip_vle_lz4.c
+++ b/drivers/staging/erofs/unzip_vle_lz4.c
@@ -136,10 +136,13 @@ int z_erofs_vle_unzip_fast_percpu(struct page **compressed_pages,
 
        nr_pages = DIV_ROUND_UP(outlen + pageofs, PAGE_SIZE);
 
-       if (clusterpages == 1)
+       if (clusterpages == 1) {
                vin = kmap_atomic(compressed_pages[0]);
-       else
+       } else {
                vin = erofs_vmap(compressed_pages, clusterpages);
+               if (!vin)
+                       return -ENOMEM;
+       }
 
        preempt_disable();
        vout = erofs_pcpubuf[smp_processor_id()].data;