[Buildroot] [PATCH v7 03/18] core: re-enter make if $(CURDIR) or $(O) are not absolute canonical path

[Yann E. MORIN <yann.morin.1998@free.fr>]

Samuel, All,

On 2016-03-09 23:58 +0100, Samuel Martin spake thusly:
> When $(CURDIR) or $(O) contain symlinks (or mount-bind) in their path,
> they can be resolved differently, depending on each package build-system
> (whether it uses the given paths or get the absolute canonical ones).
> 
> Thus, to make easier tracking down host machine paths leaking into the
> host, target or staging trees, the CURDIR and O variables are set to
> their absolute canonical paths.
> 
> Note that this change takes care of the makefile wrapper installed in
> $(O) to avoid unneeded make recursion.
> 
> Signed-off-by: Samuel Martin <s.martin49@gmail.com>
> 
> ---
> changes v6->v7:
> - none
> 
> changes v5->v6:
> - new patch
> ---
>  Makefile | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 98c8dc7..52a92f6 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -26,16 +26,30 @@
>  
>  # Trick for always running with a fixed umask
>  UMASK = 0022
> -ifneq ($(shell umask),$(UMASK))
> +
> +# Check if we need to re-enter make for one or several of the following reasons:
> +# 1- Wrong (too restrictive) umask:
> +#    This prevents Buildroot and packages from creating files and directories.
> +# 2- CWD (i.e. $(CURDIR)) not being the absolute canonical path:
> +#    This makes harder tracking and fixing host machine path leaks.
> +# 3- Output location (i.e. $(O)) not being the absolute canonical path:
> +#    This makes harder tracking and fixing host machine path leaks.
> +#
> +# Note:
> +# - remove the trailing '/.' from $(O) as it can be added by the makefile
> +#   wrapper installed in the $(O).
> +ifneq ($(shell umask):$(CURDIR):$(patsubst %/.,%,$(O)),$(UMASK):$(realpath $(CURDIR)):$(realpath $(O)))

This is a bit difficult to parse. What about setting intermediate
variables, like so:

    CUR_UMASK := $(shell umask)
    REAL_CURDIR := $(realpath $(CURDIR))
    O := $(patsubst %/.,%,$(O))
    REAL_O := $(realpath $(O))

    ifneq ($(CUR_UMASK):$(CURDIR):$(O),$(UMASK):$(REAL_CURDIR):$(REAL_O))

>  .PHONY: _all $(MAKECMDGOALS)
>  
>  $(MAKECMDGOALS): _all
>  	@:
>  
>  _all:
> -	@umask $(UMASK) && $(MAKE) --no-print-directory $(MAKECMDGOALS)
> +	umask $(UMASK) && \

Please keep the command silent, do not remove the leading @

Regards,
Yann E. MORIN.

> +		$(MAKE) -C $(realpath $(CURDIR)) --no-print-directory \
> +			$(MAKECMDGOALS) O=$(realpath $(O))
>  
> -else # umask
> +else # umask / $(CURDIR) / $(O)
>  
>  # This is our default rule, so must come first
>  all:
> @@ -1007,4 +1021,4 @@ include docs/manual/manual.mk
>  
>  .PHONY: $(noconfig_targets)
>  
> -endif #umask
> +endif #umask / $(CURDIR) / $(O)
> -- 
> 2.7.2
> 
> _______________________________________________
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> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

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