[SCM] GNU Autoconf source repository branch, master, updated. v2.69-131-g247b02e

[Eric Blake]

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- Log -----------------------------------------------------------------
commit 247b02e5a5bb79ca6666e91de02ae2d3cb0cd325
Author: Gary V. Vaughan <address@hidden>
Date:   Mon Nov 3 07:25:03 2014 +0100

    tests: avoid spurious test failure with libtool 2.4.3
    
    Based on a report by Bruce Dubbs.
    
    * tests/foreign.at (Libtool): Be tolerant of 'quote' replacing the
    older `quote'.
    
    Signed-off-by: Eric Blake <address@hidden>

commit 36b77d7db8371ef0e486e44a4ab0e7afb55bed6a
Author: Eric Blake <address@hidden>
Date:   Sat Sep 27 18:24:06 2014 -0600

    docs: mention that not all values can be exported
    
    There has been a LOT of news about bash's Shell Shock bug lately.
    Document some of the ramifications it has on portable scripting.
    
    * doc/autoconf.texi (Limitations of Builtins) <export>: Add some
    details about Shell Shock CVE-2014-6271.
    
    Signed-off-by: Eric Blake <address@hidden>

-----------------------------------------------------------------------

Summary of changes:
 doc/autoconf.texi |   23 +++++++++++++++++++++++
 tests/foreign.at  |    2 +-
 2 files changed, 24 insertions(+), 1 deletions(-)

diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index e2137ae..ace1675 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -17668,6 +17668,29 @@ $ @kbd{/bin/sh -c 'export foo; foo=bar; echo $foo'}
 bar
 @end example
 
+Posix requires @command{export} to work with any arbitrary value for the
+contents of the variable being exported, as long as the total size of
+the environment combined with arguments doesn't exceed @code{ARG_MAX}
+when executing a child process.  However, some shells have extensions
+that involve interpreting some environment values specially, regardless
+of the variable name.  We currently know of one case: all versions of
+Bash released prior to 27 September 2014 intepret an environment
+variable with an initial content substring of @code{() @{} as an
+exported function definition (this is the ``Shellshock'' remote
+execution bug, CVE-2014-6271 and friends, where it was possible to
+eploit the function parser to cause remote code execution on child bash
+startup; newer versions of Bash use special environment variable
address@hidden instead of values to implement the same feature).
+
+There may be entries inherited into the environment that are not valid
+as shell variable names; Posix states that processes should be tolerant
+of these names.  Some shells such as @command{dash} do this by removing
+those names from the environment at startup, while others such as
address@hidden hide the entry from shell access but still pass it on to
+child processes.  While you can set such names using @command{env} for a
+direct child process, you cannot rely on them being preserved through an
+intermediate pass through the shell.
+
 @item @command{false}
 @c ------------------
 @prindex @command{false}
diff --git a/tests/foreign.at b/tests/foreign.at
index a9dc33c..d4702cd 100644
--- a/tests/foreign.at
+++ b/tests/foreign.at
@@ -57,7 +57,7 @@ AT_CHECK([./config.guess || exit 77], [], [ignore], [ignore])
 # Make sure at-path contains something valid, and let the test suite
 # display it when verbose.  And fail, skipping would too easily hide
 # problems.
-AT_CHECK([sed -n ["s,^.*\`\\(/[^']*\\)'.*,\\1,p"] stdout], [0], [stdout])
+AT_CHECK([sed -n ["s,^[^']*[\`']\\(/[^']*\\)'.*,\\1,p"] stdout], [0], [stdout])
 AT_CHECK([test -f "`sed -n 1p stdout`"])
 
 # Older libtoolize installed everything but install-sh...


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