From edfd3bc4c1057be0b5553b5789a44f1b77bb2b45 Mon Sep 17 00:00:00 2001 From: Stefano Lattarini Date: Sun, 17 Feb 2013 16:42:46 +0100 Subject: tar: format 'ustar' cannot support UID/GID longer than 21 bits See automake bug#8343 and bug#13588. POSIX 1988 'ustar' format is defined with *fixed-size* fields. There is notably a 21 bits limit (2097151) for the UID and the GID. Tom Rini tom_rini@mentor.com says (in bug#8343): When the user has a UID or GID that is larger than the ustar format supports, pax does not error out gracefully in some cases (FC13). Marc Herbert adds (in bug#8343): When "configure" is run by a user with an UID bigger than 21 bits, BSD pax 3.4 aborts when trying to create the 'conftest.tar' test archive and leaves an empty or corrupted conftest.tar file behind. In the next step, pax tries to extract this incomplete or corrupted archive and this *** hangs the whole ./configure script ***. Note: GNU cpio 2.9 pretends to pass the test but it is a LIE: it silently truncates any big UID to its lower 21 bits. I don't know what can be the consequences of this lie. I think there is currently a design issue in automake/m4/tar.m4 considering that a ustar archive should should *never* succeed when ./configure is run from a big user ID. Months later, Petr Hracek reports a similar issue (in bug#13588) for Fedora 17: I am trying to solve problem in case a user is created with big UID and during configuration pax hangs with message ATTENTION! pax archive volume change required. Ready for archive volume: 1 Input archive name or "." to quit pax. Archive name > and needs user interaction. Reference: Time to fix this issue, on the line of a preliminary patch provided by Petr Hracek in bug#13588. The final patch ended up being remarkably different from that original proposition, though. * m4/tar.m4 (_AM_PROG_TAR): If the UID or GID of the current user is too high (> 2097151), the 'ustar' format cannot work. Adjust checks accordingly. Some related code reordering and clean-up. * t/tar-ustar-id-too-high.sh: New test. * t/list-of-tests.mk: Add it. * t/tar.sh: While at it, tweak and enhance a little. * t/tar2.sh: Likewise. * t/tar3.sh: Likewise. * t/tar-override.sh: Likewise. * NEWS: Update. * THANKS: Likewise. Helped-by: Pavel Raiskup Helped-by: Petr Hracek Helped-by: Marc Herbert Helped-by: Tom Rini Signed-off-by: Stefano Lattarini --- m4/tar.m4 | 160 ++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 99 insertions(+), 61 deletions(-) (limited to 'm4') diff --git a/m4/tar.m4 b/m4/tar.m4 index ec8c83e4c..aac6d8f04 100644 --- a/m4/tar.m4 +++ b/m4/tar.m4 @@ -19,76 +19,114 @@ # Substitute a variable $(am__untar) that extract such # a tarball read from stdin. # $(am__untar) < result.tar +# AC_DEFUN([_AM_PROG_TAR], [# Always define AMTAR for backward compatibility. Yes, it's still used # in the wild :-( We should find a proper way to deprecate it ... AC_SUBST([AMTAR], ['$${TAR-tar}']) -m4_if([$1], [v7], - [am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'], - [m4_case([$1], [ustar],, [pax],, - [m4_fatal([Unknown tar format])]) -AC_MSG_CHECKING([how to create a $1 tar archive]) -# Loop over all known methods to create a tar archive until one works. + +# We'll loop over all known methods to create a tar archive until one works. _am_tools='gnutar m4_if([$1], [ustar], [plaintar]) pax cpio none' -_am_tools=${am_cv_prog_tar_$1-$_am_tools} -# Do not fold the above two line into one, because Tru64 sh and -# Solaris sh will not grok spaces in the rhs of '-'. -for _am_tool in $_am_tools -do - case $_am_tool in - gnutar) - for _am_tar in tar gnutar gtar; - do - AM_RUN_LOG([$_am_tar --version]) && break - done - am__tar="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"' - am__tar_="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"' - am__untar="$_am_tar -xf -" - ;; - plaintar) - # Must skip GNU tar: if it does not support --format= it doesn't create - # ustar tarball either. - (tar --version) >/dev/null 2>&1 && continue - am__tar='tar chf - "$$tardir"' - am__tar_='tar chf - "$tardir"' - am__untar='tar xf -' - ;; - pax) - am__tar='pax -L -x $1 -w "$$tardir"' - am__tar_='pax -L -x $1 -w "$tardir"' - am__untar='pax -r' - ;; - cpio) - am__tar='find "$$tardir" -print | cpio -o -H $1 -L' - am__tar_='find "$tardir" -print | cpio -o -H $1 -L' - am__untar='cpio -i -H $1 -d' - ;; - none) - am__tar=false - am__tar_=false - am__untar=false - ;; - esac - # If the value was cached, stop now. We just wanted to have am__tar - # and am__untar set. - test -n "${am_cv_prog_tar_$1}" && break +m4_if([$1], [v7], + [am__tar='$${TAR-tar} chof - "$$tardir"' am__untar='$${TAR-tar} xf -'], - # tar/untar a dummy directory, and stop if the command works - rm -rf conftest.dir - mkdir conftest.dir - echo GrepMe > conftest.dir/file - AM_RUN_LOG([tardir=conftest.dir && eval $am__tar_ >conftest.tar]) + [m4_case([$1], + [ustar], + [# The POSIX 1988 'ustar' format is defined with fixed-size fields. + # There is notably a 21 bits limit for the UID and the GID. In fact, + # the 'pax' utility can hang on bigger UID/GID (see automake bug#8343 + # and bug#13588). + am_max_uid=2097151 # 2^21 - 1 + am_max_gid=$am_max_uid + # The $UID and $GID variables are not portable, so we need to resort + # to the POSIX-mandated id(1) utility. Errors in the 'id' calls + # below are definitely unexpected, so allow the users to see them + # (that is, avoid stderr redirection). + am_uid=`id -u || echo unknown` + am_gid=`id -g || echo unknown` + AC_MSG_CHECKING([whether UID '$am_uid' is supported by ustar format]) + if test $am_uid -le $am_max_uid; then + AC_MSG_RESULT([yes]) + else + AC_MSG_RESULT([no]) + _am_tools=none + fi + AC_MSG_CHECKING([whether GID '$am_gid' is supported by ustar format]) + if test $am_gid -le $am_max_gid; then + AC_MSG_RESULT([yes]) + else + AC_MSG_RESULT([no]) + _am_tools=none + fi], + + [pax], + [], + + [m4_fatal([Unknown tar format])]) + + AC_MSG_CHECKING([how to create a $1 tar archive]) + + # Go ahead even if we have the value already cached. We do so because we + # need to set the values for the 'am__tar' and 'am__untar' variables. + _am_tools=${am_cv_prog_tar_$1-$_am_tools} + + for _am_tool in $_am_tools; do + case $_am_tool in + gnutar) + for _am_tar in tar gnutar gtar; do + AM_RUN_LOG([$_am_tar --version]) && break + done + am__tar="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$$tardir"' + am__tar_="$_am_tar --format=m4_if([$1], [pax], [posix], [$1]) -chf - "'"$tardir"' + am__untar="$_am_tar -xf -" + ;; + plaintar) + # Must skip GNU tar: if it does not support --format= it doesn't create + # ustar tarball either. + (tar --version) >/dev/null 2>&1 && continue + am__tar='tar chf - "$$tardir"' + am__tar_='tar chf - "$tardir"' + am__untar='tar xf -' + ;; + pax) + am__tar='pax -L -x $1 -w "$$tardir"' + am__tar_='pax -L -x $1 -w "$tardir"' + am__untar='pax -r' + ;; + cpio) + am__tar='find "$$tardir" -print | cpio -o -H $1 -L' + am__tar_='find "$tardir" -print | cpio -o -H $1 -L' + am__untar='cpio -i -H $1 -d' + ;; + none) + am__tar=false + am__tar_=false + am__untar=false + ;; + esac + + # If the value was cached, stop now. We just wanted to have am__tar + # and am__untar set. + test -n "${am_cv_prog_tar_$1}" && break + + # tar/untar a dummy directory, and stop if the command works. + rm -rf conftest.dir + mkdir conftest.dir + echo GrepMe > conftest.dir/file + AM_RUN_LOG([tardir=conftest.dir && eval $am__tar_ >conftest.tar]) + rm -rf conftest.dir + if test -s conftest.tar; then + AM_RUN_LOG([$am__untar /dev/null 2>&1 && break + fi + done rm -rf conftest.dir - if test -s conftest.tar; then - AM_RUN_LOG([$am__untar /dev/null 2>&1 && break - fi -done -rm -rf conftest.dir -AC_CACHE_VAL([am_cv_prog_tar_$1], [am_cv_prog_tar_$1=$_am_tool]) -AC_MSG_RESULT([$am_cv_prog_tar_$1])]) + AC_CACHE_VAL([am_cv_prog_tar_$1], [am_cv_prog_tar_$1=$_am_tool]) + AC_MSG_RESULT([$am_cv_prog_tar_$1])]) + AC_SUBST([am__tar]) AC_SUBST([am__untar]) ]) # _AM_PROG_TAR -- cgit v1.2.1