Re: [PATCH] tools/xenstore: avoid unterminated string in xs_directory_part()

[Wei Liu <wei.liu2@citrix.com>]

On Tue, Dec 06, 2016 at 07:41:54AM +0100, Juergen Gross wrote:
> Commit d4016288ab1f ("xenstore: support XS_DIRECTORY_PART in
> libxenstore") introduced a theoretical bug: the generation count of
> the read node is transferred via strncpy without forcing a NUL byte
> at the end. Correct this.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

> ---
>  tools/xenstore/xs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c
> index e462a20..3ce7157 100644
> --- a/tools/xenstore/xs.c
> +++ b/tools/xenstore/xs.c
> @@ -589,7 +589,7 @@ static char **xs_directory_part(struct xs_handle *h, xs_transaction_t t,
>  	struct iovec iovec[2];
>  	char *result = NULL, *strings = NULL;
>  
> -	gen[0] = 0;
> +	memset(gen, 0, sizeof(gen));
>  	iovec[0].iov_base = (void *)path;
>  	iovec[0].iov_len = strlen(path) + 1;
>  
> @@ -616,7 +616,7 @@ static char **xs_directory_part(struct xs_handle *h, xs_transaction_t t,
>  				continue;
>  			}
>  		} else
> -			strncpy(gen, result, sizeof(gen));
> +			strncpy(gen, result, sizeof(gen) - 1);
>  
>  		result_len -= strlen(result) + 1;
>  		strings = realloc(strings, off + result_len);
> -- 
> 2.10.2
> 

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