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authorAmir Goldstein <amir73il@gmail.com>2018-07-17 16:05:38 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2018-07-17 17:04:34 +0300
commit67810693077afc1ebf9e1646af300436cb8103c2 (patch)
tree4680beac9b17af390ad8fcd176851a6eacab4877 /fs/overlayfs/readdir.c
parentce397d215ccd07b8ae3f71db689aedb85d56ab40 (diff)
downloadlinux-67810693077afc1ebf9e1646af300436cb8103c2.tar.xz
ovl: fix wrong use of impure dir cache in ovl_iterate()
Only upper dir can be impure, but if we are in the middle of iterating a lower real dir, dir could be copied up and marked impure. We only want the impure cache if we started iterating a real upper dir to begin with. Aditya Kali reported that the following reproducer hits the WARN_ON(!cache->refcount) in ovl_get_cache(): docker run --rm drupal:8.5.4-fpm-alpine \ sh -c 'cd /var/www/html/vendor/symfony && \ chown -R www-data:www-data . && ls -l .' Reported-by: Aditya Kali <adityakali@google.com> Tested-by: Aditya Kali <adityakali@google.com> Fixes: 4edb83bb1041 ('ovl: constant d_ino for non-merge dirs') Cc: <stable@vger.kernel.org> # v4.14 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs/readdir.c')
-rw-r--r--fs/overlayfs/readdir.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index ef1fe42ff7bb..cc8303a806b4 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -668,6 +668,21 @@ static int ovl_fill_real(struct dir_context *ctx, const char *name,
return orig_ctx->actor(orig_ctx, name, namelen, offset, ino, d_type);
}
+static bool ovl_is_impure_dir(struct file *file)
+{
+ struct ovl_dir_file *od = file->private_data;
+ struct inode *dir = d_inode(file->f_path.dentry);
+
+ /*
+ * Only upper dir can be impure, but if we are in the middle of
+ * iterating a lower real dir, dir could be copied up and marked
+ * impure. We only want the impure cache if we started iterating
+ * a real upper dir to begin with.
+ */
+ return od->is_upper && ovl_test_flag(OVL_IMPURE, dir);
+
+}
+
static int ovl_iterate_real(struct file *file, struct dir_context *ctx)
{
int err;
@@ -696,7 +711,7 @@ static int ovl_iterate_real(struct file *file, struct dir_context *ctx)
rdt.parent_ino = stat.ino;
}
- if (ovl_test_flag(OVL_IMPURE, d_inode(dir))) {
+ if (ovl_is_impure_dir(file)) {
rdt.cache = ovl_cache_get_impure(&file->f_path);
if (IS_ERR(rdt.cache))
return PTR_ERR(rdt.cache);
@@ -727,7 +742,7 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx)
*/
if (ovl_xino_bits(dentry->d_sb) ||
(ovl_same_sb(dentry->d_sb) &&
- (ovl_test_flag(OVL_IMPURE, d_inode(dentry)) ||
+ (ovl_is_impure_dir(file) ||
OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) {
return ovl_iterate_real(file, ctx);
}