From: Gao Xiang Date: Sun, 18 Aug 2019 12:54:57 +0000 (+0800) Subject: staging: erofs: fix an error handling in erofs_readdir() X-Git-Tag: v5.4-rc1~134^2~124 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=acb383f1dcb4f1e79b66d4be3a0b6f519a957b0d;p=thirdparty%2Fkernel%2Flinux.git staging: erofs: fix an error handling in erofs_readdir() 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/erofs/dir.c b/drivers/staging/erofs/dir.c index 5f38382637e6c..77ef856df9f3a 100644 --- a/drivers/staging/erofs/dir.c +++ b/drivers/staging/erofs/dir.c @@ -82,8 +82,15 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx) unsigned int 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 = -EFSCORRUPTED; + break; + } de = (struct erofs_dirent *)kmap(dentry_page);