On Fri, Feb 04, 2022 at 06:56:57PM +0100, Jan Kara wrote:
> Add test checking functionality of seekdir. We check whether seekdir
> gets us back to the directory entry it should and also whether seeking
> to random positions does not crash the filesystem.
>
> Unlike test generic/310 which also tests seeking, this test checks both
> glibc readdir() function as well as getdents64() syscall directly. This
> is because glibc readdir() implementation does a lot of caching and
> processing internally thus hiding kernel from some possible problems.
> Also test wider range of random offsets to have better chance of
> hitting out of bound accesses or other bugs.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> src/Makefile | 2 +-
> src/t_readdir_3.c | 239 ++++++++++++++++++++++++++++++++++++++++++
> tests/generic/673 | 41 ++++++++
> tests/generic/673.out | 2 +
> 4 files changed, 283 insertions(+), 1 deletion(-)
> create mode 100644 src/t_readdir_3.c
> create mode 100755 tests/generic/673
> create mode 100644 tests/generic/673.out
>
> diff --git a/src/Makefile b/src/Makefile
> index 111ce1d90fe6..4d9e02b74d13 100644
> --- a/src/Makefile
> +++ b/src/Makefile
> @@ -31,7 +31,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
> dio-invalidate-cache stat_test t_encrypted_d_revalidate \
> attr_replace_test swapon mkswap t_attr_corruption t_open_tmpfiles \
> fscrypt-crypt-util bulkstat_null_ocount splice-test chprojid_fail \
> - detached_mounts_propagation ext4_resize
> + detached_mounts_propagation ext4_resize t_readdir_3
>
> EXTRA_EXECS = dmerror fill2attr fill2fs fill2fs_check scaleread.sh \
> btrfs_crc32c_forged_name.py
> diff --git a/src/t_readdir_3.c b/src/t_readdir_3.c
> new file mode 100644
> index 000000000000..804138971dcd
> --- /dev/null
> +++ b/src/t_readdir_3.c
> @@ -0,0 +1,239 @@
> +#define _LARGEFILE64_SOURCE
> +#include <unistd.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <dirent.h>
> +#include <fcntl.h>
> +#include <limits.h>
> +#include <errno.h>
> +#include <stdint.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <sys/syscall.h>
> +
> +/* Our own declaration taken from the kernel since glibc does not have it... */
> +struct linux_dirent64 {
> + uint64_t d_ino;
> + int64_t d_off;
> + unsigned short d_reclen;
> + unsigned char d_type;
> + char d_name[];
> +};
> +
> +#define MIN_NAME_LEN 8
> +#define MAX_NAME_LEN 70
> +
> +static DIR *dir;
> +static int dfd;
> +static int ignore_error;
> +
> +struct dir_ops {
> + loff_t (*getpos)(void);
> + void (*setpos)(loff_t pos);
> + void (*getentry)(struct dirent *entry);
> +};
> +
> +static off64_t libc_getpos(void)
> +{
> + return telldir(dir);
> +}
> +
> +static void libc_setpos(off64_t pos)
> +{
> + seekdir(dir, pos);
> +}
> +
> +static void libc_getentry(struct dirent *entry)
> +{
> + struct dirent *ret;
> +
> + errno = 0;
> + ret = readdir(dir);
> + if (!ret) {
> + if (errno == 0) {
> + fprintf(stderr, "Unexpected EOF while reading dir.\n");
> + exit(1);
> + }
> + if (ignore_error)
> + return;
> + perror("readdir");
> + exit(1);
> + }
> + memcpy(entry, ret, sizeof(struct dirent));
> +}
> +
> +static off64_t kernel_getpos(void)
> +{
> + return lseek64(dfd, 0, SEEK_CUR);
> +}
> +
> +static void kernel_setpos(off64_t pos)
> +{
> + lseek64(dfd, pos, SEEK_SET);
> +}
> +
> +static void kernel_getentry(struct dirent *entry)
> +{
> + char dirbuf[NAME_MAX + 1 + sizeof(struct linux_dirent64)];
> + struct linux_dirent64 *lentry = (struct linux_dirent64 *)dirbuf;
> + int ret;
> +
> + ret = syscall(SYS_getdents64, dfd, lentry, sizeof(dirbuf));
> + if (ret < 0) {
> + if (ignore_error)
> + return;
> + perror("getdents64");
> + exit(1);
> + }
> + if (ret == 0) {
> + fprintf(stderr, "Unexpected EOF while reading dir.\n");
> + exit(1);
> + }
> + entry->d_ino = lentry->d_ino;
> + entry->d_off = lentry->d_off;
> + entry->d_reclen = lentry->d_reclen;
> + entry->d_type = lentry->d_type;
> + strcpy(entry->d_name, lentry->d_name);
> +}
> +
> +struct dir_ops libc_ops = {
> + .getpos = libc_getpos,
> + .setpos = libc_setpos,
> + .getentry = libc_getentry,
> +};
> +
> +struct dir_ops kernel_ops = {
> + .getpos = kernel_getpos,
> + .setpos = kernel_setpos,
> + .getentry = kernel_getentry,
> +};
> +
> +static void create_dir(char *dir, int count)
> +{
> + int i, j, len;
> + char namebuf[MAX_NAME_LEN];
> + int dfd, fd;
> +
> + dfd = open(dir, O_RDONLY | O_DIRECTORY);
> + if (dfd < 0) {
> + perror("Cannot open dir");
> + exit(1);
> + }
> + for (i = 0; i < count; i++) {
> + len = random() % (MAX_NAME_LEN - MIN_NAME_LEN) + MIN_NAME_LEN;
> + for (j = 0; j < len; j++)
> + namebuf[j] = random() % 26 + 'a';
> + namebuf[len] = 0;
> +
> + fd = openat(dfd, namebuf, O_RDWR | O_CREAT | O_EXCL, 0644);
> + if (fd < 0) {
> + if (errno == EEXIST) {
> + /* Try again */
> + i--;
> + continue;
> + }
> + perror("File creation failed");
> + exit(1);
> + }
> + close(fd);
> + }
> + close(dfd);
> +}
> +
> +static void test(int count, struct dir_ops *ops)
> +{
> + struct dirent *dbuf;
> + struct dirent entry;
> + loff_t *pbuf;
> + loff_t dpos, maxpos = 0;
> + int i, pos;
> +
> + dbuf = calloc(count, sizeof(struct dirent));
> + pbuf = calloc(count, sizeof(loff_t));
> + if (!dbuf || !pbuf) {
> + fprintf(stderr, "Out of memory for buffers.\n");
> + exit(1);
> + }
> +
> + for (i = 0; i < count; i++) {
> + pbuf[i] = ops->getpos();
> + if (pbuf[i] > maxpos)
> + maxpos = pbuf[i];
> + ops->getentry(dbuf + i);
> + ops->setpos(dbuf[i].d_off);
> + }
> +
> + for (i = 0; i < count; i++) {
> + pos = random() % count;
> + ops->setpos(pbuf[pos]);
> + ops->getentry(&entry);
> + if (dbuf[pos].d_ino != entry.d_ino ||
> + dbuf[pos].d_type != entry.d_type ||
> + strcmp(dbuf[pos].d_name, entry.d_name)) {
> + fprintf(stderr,
> + "Mismatch in dir entry %u at pos %llu\n", pos,
> + (unsigned long long)pbuf[pos]);
> +
> + exit(1);
> + }
> + }
> + puts("Reading valid entries passed.");
> +
> + ignore_error = 1;
> + for (i = 0; i < count; i++) {
> + dpos = random() % maxpos;
> + ops->setpos(dpos);
> + /*
> + * We don't care about the result but the kernel should not
> + * crash.
> + */
> + ops->getentry(&entry);
> + }
> + ignore_error = 0;
> +
> + puts("Reading random positions passed.");
> + free(dbuf);
> + free(pbuf);
> +}
> +
> +int main(int argc, char *argv[])
> +{
> + int count;
> + unsigned long seed;
> +
> + if (argc != 4) {
> + fprintf(stderr, "Usage: t_seekdir_3 <dir> <count> <seed>\n");
> + return 1;
> + }
> +
> + count = atoi(argv[2]);
> + seed = atol(argv[3]);
> +
> + srandom(seed);
> +
> + create_dir(argv[1], count);
> +
> + puts("Testing readdir...");
> + dir = opendir(argv[1]);
> + if (!dir) {
> + perror("Cannot open dir");
> + exit(1);
> + }
> + test(count, &libc_ops);
> + closedir(dir);
> + dir = NULL;
> +
> + puts("Testing getdents...");
> + dfd = open(argv[1], O_DIRECTORY | O_RDONLY);
> + if (dfd < 0) {
> + perror("Cannot open dir");
> + exit(1);
> + }
> + test(count, &kernel_ops);
> + close(dfd);
> + dfd = 0;
> + fprintf(stderr, "All tests passed\n");
> +
> + return 0;
> +}
> diff --git a/tests/generic/673 b/tests/generic/673
> new file mode 100755
> index 000000000000..f6dea54db1a6
> --- /dev/null
> +++ b/tests/generic/673
> @@ -0,0 +1,41 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2022 YOUR NAME HERE. All Rights Reserved.
I forgot this in my first email, "YOUR NAME HERE" should be updated
accordingly as well.
Thanks,
Eryu
> +#
> +# FS QA Test 673
> +#
> +# Test that filesystem properly handles seeking in directory both to valid
> +# and invalid positions.
> +#
> +# This is a regression test for a48fc69fe658 ("udf: Fix crash after seekdir")
> +#
> +. ./common/preamble
> +_begin_fstest auto quick
> +
> +dir=$TEST_DIR/$seq-dir
> +
> +# Override the default cleanup function.
> +_cleanup()
> +{
> + rm -rf $dir
> +}
> +
> +# Import common functions.
> +# . ./common/filter
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs generic
> +_require_test
> +
> +files=4000
> +seed=$RANDOM
> +
> +mkdir $dir
> +echo "Using seed $seed" >> $seqres.full
> +$here/src/t_readdir_3 $dir $files $seed >> $seqres.full
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/generic/673.out b/tests/generic/673.out
> new file mode 100644
> index 000000000000..e038de2ca346
> --- /dev/null
> +++ b/tests/generic/673.out
> @@ -0,0 +1,2 @@
> +QA output created by 673
> +All tests passed
> --
> 2.31.1
