Re: [PATCH 3/5] xfs_logprint: fix some unaligned accesses

[Brian Foster <bfoster@redhat.com>]

On Fri, Oct 09, 2015 at 02:52:16PM -0500, Eric Sandeen wrote:
> This routine had a fair bit of gyration to avoid unaligned
> accesses, but didn't fix them all.
> Fix some more spotted at runtime by libubsan.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> V2: Change variable scope, remove extraneous hunk
> 

Thanks!

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  logprint/log_misc.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/logprint/log_misc.c b/logprint/log_misc.c
> index d76145c..4cdcbec 100644
> --- a/logprint/log_misc.c
> +++ b/logprint/log_misc.c
> @@ -243,9 +243,6 @@ int
>  xlog_print_trans_buffer(char **ptr, int len, int *i, int num_ops)
>  {
>      xfs_buf_log_format_t *f;
> -    xfs_agi_t		 *agi;
> -    xfs_agf_t		 *agf;
> -    xfs_disk_dquot_t	 *dq;
>      xlog_op_header_t	 *head = NULL;
>      int			 num, skip;
>      int			 super_block = 0;
> @@ -325,7 +322,11 @@ xlog_print_trans_buffer(char **ptr, int len, int *i, int num_ops)
>  		}
>  		super_block = 0;
>  	} else if (be32_to_cpu(*(__be32 *)(*ptr)) == XFS_AGI_MAGIC) {
> -		agi = (xfs_agi_t *)(*ptr);
> +  	  	struct xfs_agi	*agi, agi_s;
> +
> +		/* memmove because *ptr may not be 8-byte aligned */
> +		agi = &agi_s;
> +		memmove(agi, *ptr, sizeof(struct xfs_agi));
>  		printf(_("AGI Buffer: XAGI  "));
>  		/*
>  		 * v4 filesystems only contain the fields before the uuid.
> @@ -375,7 +376,11 @@ xlog_print_trans_buffer(char **ptr, int len, int *i, int num_ops)
>  			}
>  		}
>  	} else if (be32_to_cpu(*(__be32 *)(*ptr)) == XFS_AGF_MAGIC) {
> -		agf = (xfs_agf_t *)(*ptr);
> +    		struct xfs_agf	*agf, agf_s;
> +
> +		/* memmove because *ptr may not be 8-byte aligned */
> +		agf = &agf_s;
> +		memmove(agf, *ptr, sizeof(struct xfs_agf));
>  		printf(_("AGF Buffer: XAGF  "));
>  		/*
>  		 * v4 filesystems only contain the fields before the uuid.
> @@ -408,7 +413,11 @@ xlog_print_trans_buffer(char **ptr, int len, int *i, int num_ops)
>  				be32_to_cpu(agf->agf_longest));
>  		}
>  	} else if (be32_to_cpu(*(__be32 *)(*ptr)) == XFS_DQUOT_MAGIC) {
> -		dq = (xfs_disk_dquot_t *)(*ptr);
> +		struct xfs_disk_dquot *dq, dq_s;
> +
> +		/* memmove because *ptr may not be 8-byte aligned */
> +		dq = &dq_s;
> +		memmove(dq, *ptr, sizeof(struct xfs_disk_dquot));
>  		printf(_("DQUOT Buffer: DQ  "));
>  		if (be32_to_cpu(head->oh_len) <
>  				sizeof(xfs_disk_dquot_t)) {
> -- 
> 2.6.1
> 
> 
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