From e7c44410387c99039df28ffcbdaa5ff85ab5e857 Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Wed, 9 Oct 2019 18:12:36 +0800 Subject: [PATCH] staging: erofs: fix an error handling in erofs_readdir() commit acb383f1dcb4f1e79b66d4be3a0b6f519a957b0d upstream. Richard observed a forever loop of erofs_read_raw_page() [1] which can be generated by forcely setting ->u.i_blkaddr to 0xdeadbeef (as my understanding block layer can handle access beyond end of device correctly). After digging into that, it seems the problem is highly related with directories and then I found the root cause is an improper error handling in erofs_readdir(). Let's fix it now. [1] https://lore.kernel.org/r/1163995781.68824.1566084358245.JavaMail.zimbra@nod.at/ Reported-by: Richard Weinberger Fixes: 3aa8ec716e52 ("staging: erofs: add directory operations") Cc: # 4.19+ Reviewed-by: Chao Yu Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20190818125457.25906-1-hsiangkao@aol.com [ Gao Xiang: Since earlier kernels don't define EFSCORRUPTED, let's use original error code instead. ] Signed-off-by: Gao Xiang Signed-off-by: Greg Kroah-Hartman --- drivers/staging/erofs/dir.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/staging/erofs/dir.c b/drivers/staging/erofs/dir.c index 0a089cf5c78f..fe6683effd05 100644 --- a/drivers/staging/erofs/dir.c +++ b/drivers/staging/erofs/dir.c @@ -100,8 +100,15 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) unsigned nameoff, maxsize; dentry_page = read_mapping_page(mapping, i, NULL); - if (IS_ERR(dentry_page)) - continue; + if (dentry_page == ERR_PTR(-ENOMEM)) { + err = -ENOMEM; + break; + } else if (IS_ERR(dentry_page)) { + errln("fail to readdir of logical block %u of nid %llu", + i, EROFS_V(dir)->nid); + err = PTR_ERR(dentry_page); + break; + } lock_page(dentry_page); de = (struct erofs_dirent *)kmap(dentry_page); -- GitLab