Re: [PATCH] exportfs: Fix buf size in test_export() dump().

[Steve Dickson <SteveD@redhat.com>]

On 11/03/2015 10:43 PM, stevens.yin wrote:
> From: Jianhong Yin <jiyin@redhat.com>
> 
> The buf[] size in test_export() is not enough for NFS_MAXPATHLEN
> + prefix/suffix proto string. Fix it and same issue in dump().
> And just to be on the safe side, %s/sprintf/snprintf/
Next time please add a proper Signed-off-by line. Since
I do know the history of this patch I did the Signed-off-by.

Committed...

steved.

> ---
>  utils/exportfs/exportfs.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/utils/exportfs/exportfs.c b/utils/exportfs/exportfs.c
> index 8758231..c7a79a6 100644
> --- a/utils/exportfs/exportfs.c
> +++ b/utils/exportfs/exportfs.c
> @@ -499,9 +499,10 @@ unexportfs(char *arg, int verbose)
>  
>  static int can_test(void)
>  {
> -	char buf[1024];
> +	char buf[1024] = { 0 };
>  	int fd;
>  	int n;
> +	size_t bufsiz = sizeof(buf);
>  
>  	fd = open("/proc/net/rpc/auth.unix.ip/channel", O_WRONLY);
>  	if (fd < 0)
> @@ -514,9 +515,9 @@ static int can_test(void)
>  	 * commit 2f74f972  (sunrpc: prepare NFS for 2038).
>  	 */
>  	if (time(NULL) > INT_TO_LONG_THRESHOLD_SECS)
> -		sprintf(buf, "nfsd 0.0.0.0 %ld -test-client-\n", LONG_MAX);
> +		snprintf(buf, bufsiz-1, "nfsd 0.0.0.0 %ld -test-client-\n", LONG_MAX);
>  	else
> -		sprintf(buf, "nfsd 0.0.0.0 %d -test-client-\n", INT_MAX);
> +		snprintf(buf, bufsiz-1, "nfsd 0.0.0.0 %d -test-client-\n", INT_MAX);
>  
>  	n = write(fd, buf, strlen(buf));
>  	close(fd);
> @@ -532,7 +533,8 @@ static int can_test(void)
>  
>  static int test_export(char *path, int with_fsid)
>  {
> -	char buf[1024];
> +	/* beside max path, buf size should take protocol str into account */
> +	char buf[NFS_MAXPATHLEN+1+64] = { 0 };
>  	char *bp = buf;
>  	int len = sizeof(buf);
>  	int fd, n;
> @@ -758,7 +760,8 @@ dumpopt(char c, char *fmt, ...)
>  static void
>  dump(int verbose, int export_format)
>  {
> -	char buf[1024];
> +	/* buf[] size should >= sizeof(struct exportent->e_path) */
> +	char buf[NFS_MAXPATHLEN+1] = { 0 };
>  	char *bp;
>  	int len;
>  	nfs_export	*exp;
>