Re: [f2fs-dev] [PATCH] f2fs_io: Fix integer multiplication overflow error in fiemap

[Chao Yu <chao@kernel.org>]

On 2023/5/23 15:24, zangyangyang1 wrote:
> When using fiemap to obtain the block address of files
> larger than 2GB ((2147483647+1) bytes), an integer
> multiplication overflow error will occur.
> This issue is caused by the following code:
>      start = atoi(argv[1]) * F2FS_BLKSIZE;
>      length = atoi(argv[2]) * F2FS_BLKSIZE;
> 
> Signed-off-by: zangyangyang1 <zangyangyang1@xiaomi.com>
> ---
>   tools/f2fs_io/f2fs_io.c | 10 +++++-----
>   1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
> index 5bc0baf..ad6b5f0 100644
> --- a/tools/f2fs_io/f2fs_io.c
> +++ b/tools/f2fs_io/f2fs_io.c
> @@ -809,15 +809,15 @@ static void do_fiemap(int argc, char **argv, const struct cmd_desc *cmd)
>          }
> 
>          memset(fm, 0, sizeof(struct fiemap));
> -       start = atoi(argv[1]) * F2FS_BLKSIZE;
> -       length = atoi(argv[2]) * F2FS_BLKSIZE;

How about?

start = (long long)atoi(argv[1]) * F2FS_BLKSIZE;
length = (long long)atoi(argv[2]) * F2FS_BLKSIZE;

Thanks,

> -       fm->fm_start = start;
> -       fm->fm_length = length;
> +       start = atoll(argv[1]);
> +       length = atoll(argv[2]);
> +       fm->fm_start = start * F2FS_BLKSIZE;
> +       fm->fm_length = length * F2FS_BLKSIZE;
> 
>          fd = xopen(argv[3], O_RDONLY | O_LARGEFILE, 0);
> 
>          printf("Fiemap: offset = %"PRIu64" len = %"PRIu64"\n",
> -                               start / F2FS_BLKSIZE, length / F2FS_BLKSIZE);
> +                               start, length);
>          if (ioctl(fd, FS_IOC_FIEMAP, fm) < 0)
>                  die_errno("FIEMAP failed");
> 
> --
> 2.40.1
> 
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