Re: [PATCH v10 02/10] qemu-binfmt-conf.sh: enforce safe tests

[Laurent Vivier]

Le 09/03/2020 à 20:19, Unai Martinez-Corral a écrit :
> All the tests are prefixed with 'x', in order to avoid risky comparisons
> (i.e. a user deliberately trying to provoke a syntax error).

With the quotes I don't see how we can provoke a syntax error.
Could you provide an example?

Thanks,
Laurent

> Signed-off-by: Unai Martinez-Corral <address@hidden>
> Reviewed-by: Laurent Vivier <address@hidden>
> ---
>  scripts/qemu-binfmt-conf.sh | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/scripts/qemu-binfmt-conf.sh b/scripts/qemu-binfmt-conf.sh
> index c728443ba2..98401f4e7c 100755
> --- a/scripts/qemu-binfmt-conf.sh
> +++ b/scripts/qemu-binfmt-conf.sh
> @@ -259,10 +259,10 @@ qemu_check_systemd() {
>  
>  qemu_generate_register() {
>      flags=""
> -    if [ "$CREDENTIAL" = "yes" ]; then
> +    if [ "x$CREDENTIAL" = "xyes" ]; then
>          flags="OC"
>      fi
> -    if [ "$PERSISTENT" = "yes" ]; then
> +    if [ "x$PERSISTENT" = "xyes" ]; then
>          flags="${flags}F"
>      fi
>  
> @@ -300,18 +300,18 @@ qemu_set_binfmts() {
>          mask=$(eval echo \$${cpu}_mask)
>          family=$(eval echo \$${cpu}_family)
>  
> -        if [ "$magic" = "" ] || [ "$mask" = "" ] || [ "$family" = "" ]; then
> +        if [ "x$magic" = "x" ] || [ "x$mask" = "x" ] || [ "x$family" = "x" 
> ]; then
>              echo "INTERNAL ERROR: unknown cpu $cpu" 1>&2
>              continue
>          fi
>  
>          qemu="$QEMU_PATH/qemu-$cpu"
> -        if [ "$cpu" = "i486" ]; then
> +        if [ "x$cpu" = "xi486" ]; then
>              qemu="$QEMU_PATH/qemu-i386"
>          fi
>  
>          qemu="$qemu$QEMU_SUFFIX"
> -        if [ "$host_family" != "$family" ]; then
> +        if [ "x$host_family" != "x$family" ]; then
>              $BINFMT_SET
>          fi
>      done
>