[PATCH] erofs-utils: fix fragmentoff overflow for large packed inode

[Gao Xiang]

(cc Khem Raj <raj.khem at gmail.com>... Since I'd like to apply this first
 and then enable _FILE_OFFSET_BITS=64 unconditionally so that we could
 clean up all hard-coded _FILE_OFFSET_BITS in the source code.)

Hi Yue,

On Tue, Dec 13, 2022 at 03:16:43PM +0800, Yue Hu wrote:
> From: Yue Hu <huyue2 at coolpad.com>
> 
> The return value of ftell() is a long int, use ftello{64} instead. Also,
> use lseek64 for large file position to avoid this error if we have it.
> And need to return at once if they fail.
> 
> Signed-off-by: Yue Hu <huyue2 at coolpad.com>
> ---
>  configure.ac    |  2 ++
>  lib/fragments.c | 34 +++++++++++++++++++++++++++++-----
>  lib/inode.c     |  9 +++++++--
>  3 files changed, 38 insertions(+), 7 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index a736ff0..5c9666a 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -190,6 +190,8 @@ AC_CHECK_FUNCS(m4_flatten([
>  	llistxattr
>  	memset
>  	realpath
> +	lseek64
> +	ftello64
>  	pread64
>  	pwrite64
>  	strdup
> diff --git a/lib/fragments.c b/lib/fragments.c
> index e69ae47..4302cd5 100644
> --- a/lib/fragments.c
> +++ b/lib/fragments.c
> @@ -3,7 +3,18 @@
>   * Copyright (C), 2022, Coolpad Group Limited.
>   * Created by Yue Hu <huyue2 at coolpad.com>
>   */
> +#ifndef _LARGEFILE_SOURCE
> +#define _LARGEFILE_SOURCE
> +#endif
> +#ifndef _LARGEFILE64_SOURCE
> +#define _LARGEFILE64_SOURCE
> +#endif
> +#ifndef _FILE_OFFSET_BITS
> +#define _FILE_OFFSET_BITS 64
> +#endif
> +#ifndef _GNU_SOURCE
>  #define _GNU_SOURCE
> +#endif
>  #include <stdlib.h>
>  #include <unistd.h>
>  #include "erofs/err.h"
> @@ -30,6 +41,13 @@ static struct list_head dupli_frags[FRAGMENT_HASHSIZE];
>  static FILE *packedfile;
>  const char *frags_packedname = "packed_file";
>  
> +#ifndef HAVE_LSEEK64
> +static inline off_t lseek64(int fd, u64 offset, int set)
> +{
> +	return lseek(fd, offset, set);
> +}
> +#endif

Could we use another function name other than native lseek64?

> +
>  static int z_erofs_fragments_dedupe_find(struct erofs_inode *inode, int fd,
>  					 u32 crc)
>  {
> @@ -53,8 +71,7 @@ static int z_erofs_fragments_dedupe_find(struct erofs_inode *inode, int fd,
>  	if (!data)
>  		return -ENOMEM;
>  
> -	ret = lseek(fd, inode->i_size - length, SEEK_SET);
> -	if (ret < 0) {
> +	if (lseek64(fd, inode->i_size - length, SEEK_SET) < 0) {
>  		ret = -errno;
>  		goto out;
>  	}
> @@ -113,8 +130,7 @@ int z_erofs_fragments_dedupe(struct erofs_inode *inode, int fd, u32 *tofcrc)
>  	if (inode->i_size <= EROFS_TOF_HASHLEN)
>  		return 0;
>  
> -	ret = lseek(fd, inode->i_size - EROFS_TOF_HASHLEN, SEEK_SET);
> -	if (ret < 0)
> +	if (lseek64(fd, inode->i_size - EROFS_TOF_HASHLEN, SEEK_SET) < 0)
>  		return -errno;
>  
>  	ret = read(fd, data_to_hash, EROFS_TOF_HASHLEN);
> @@ -192,9 +208,17 @@ void z_erofs_fragments_commit(struct erofs_inode *inode)
>  int z_erofs_pack_fragments(struct erofs_inode *inode, void *data,
>  			   unsigned int len, u32 tofcrc)
>  {
> +#ifdef HAVE_FTELLO64
> +	off64_t offset = ftello64(packedfile);
> +#else
> +	off_t offset = ftello(packedfile);
> +#endif
>  	int ret;
>  
> -	inode->fragmentoff = ftell(packedfile);
> +	if (offset < 0)
> +		return -errno;
> +
> +	inode->fragmentoff = (erofs_off_t)offset;
>  	inode->fragment_size = len;
>  
>  	if (fwrite(data, len, 1, packedfile) != 1)
> diff --git a/lib/inode.c b/lib/inode.c
> index 9de4dec..a8510f3 100644
> --- a/lib/inode.c
> +++ b/lib/inode.c
> @@ -1196,7 +1196,10 @@ struct erofs_inode *erofs_mkfs_build_special_from_fd(int fd, const char *name)
>  	struct erofs_inode *inode;
>  	int ret;
>  
> -	lseek(fd, 0, SEEK_SET);
> +	ret = lseek(fd, 0, SEEK_SET);
> +	if (ret < 0)
> +		return ERR_PTR(-errno);

This should be in a seperate patch, please don't fix it here.

> +
>  	ret = fstat64(fd, &st);
>  	if (ret)
>  		return ERR_PTR(-errno);
> @@ -1223,7 +1226,9 @@ struct erofs_inode *erofs_mkfs_build_special_from_fd(int fd, const char *name)
>  
>  	ret = erofs_write_compressed_file(inode, fd);
>  	if (ret == -ENOSPC) {
> -		lseek(fd, 0, SEEK_SET);
> +		ret = lseek(fd, 0, SEEK_SET);
> +		if (ret < 0)

Same here.

Thanks,
Gao Xiang

> +			return ERR_PTR(-errno);
>  		ret = write_uncompressed_file_from_fd(inode, fd);
>  	}
>  
> -- 
> 2.17.1