Don't source the kernel config file in shell scripts.
The config file is not a shell script and often imported from untrusted
sources.
What could possible go wrong? ;-)

Instead, read config file line by line and access config entries using a bash
array.

Cc: Sam Ravnborg <s...@ravnborg.org>
Cc: Arnaud Lacombe <lacom...@gmail.com>
Cc: Nick Bowler <nbow...@elliptictech.com>
Cc: Michal Marek <mma...@suse.cz>
Cc: Nicolas Pitre <n...@linaro.org>
Cc: Rusty Russell <ru...@rustcorp.com.au>
Fixes: 23121ca2b56b ("kbuild: create/adjust generated/autoksyms.h")
Fixes: 1f2bfbd00e46 ("kbuild: link of vmlinux moved to a script")
Signed-off-by: Richard Weinberger <rich...@nod.at>
---
Changes since v1:
 - Fixed out of tree build
---
 scripts/adjust_autoksyms.sh | 13 +++----------
 scripts/importkconf.sh      | 14 ++++++++++++++
 scripts/link-vmlinux.sh     | 23 ++++++++---------------
 3 files changed, 25 insertions(+), 25 deletions(-)
 create mode 100755 scripts/importkconf.sh

diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
index 513da1a4a2da..b72a8a0bf08a 100755
--- a/scripts/adjust_autoksyms.sh
+++ b/scripts/adjust_autoksyms.sh
@@ -39,14 +39,7 @@ case "$KBUILD_VERBOSE" in
 esac
 
 # We need access to CONFIG_ symbols
-case "${KCONFIG_CONFIG}" in
-*/*)
-       . "${KCONFIG_CONFIG}"
-       ;;
-*)
-       # Force using a file from the current directory
-       . "./${KCONFIG_CONFIG}"
-esac
+. ${KBUILD_SRC}/scripts/importkconf.sh
 
 # In case it doesn't exist yet...
 if [ -e "$cur_ksyms_file" ]; then touch "$cur_ksyms_file"; fi
@@ -62,14 +55,14 @@ EOT
 [ "$(ls -A "$MODVERDIR")" ] &&
 sed -ns -e '3{s/ /\n/g;/^$/!p;}' "$MODVERDIR"/*.mod | sort -u |
 while read sym; do
-       if [ -n "$CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX" ]; then
+       if [ -n "${KERNEL_CONFIG[CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX]}" ]; then
                sym="${sym#_}"
        fi
        echo "#define __KSYM_${sym} 1"
 done >> "$new_ksyms_file"
 
 # Special case for modversions (see modpost.c)
-if [ -n "$CONFIG_MODVERSIONS" ]; then
+if [ -n "${KERNEL_CONFIG[CONFIG_MODVERSIONS]}" ]; then
        echo "#define __KSYM_module_layout 1" >> "$new_ksyms_file"
 fi
 
diff --git a/scripts/importkconf.sh b/scripts/importkconf.sh
new file mode 100755
index 000000000000..755a9a2e9c65
--- /dev/null
+++ b/scripts/importkconf.sh
@@ -0,0 +1,14 @@
+#!/bin/bash
+#
+# helper script which reads all kconfig keys from the kernel .config file into
+# a bash associative array.
+# By testing ${KERNEL_CONFIG[CONFIG_FOO_BAR]} shell scripts can check whether
+# CONFIG_FOO_BAR is set in .config or not.
+#
+
+declare -A KERNEL_CONFIG
+
+for cfg_ent in $(awk -F= '/^CONFIG_[A-Z0-9_]+=/{print $1}' < ${KCONFIG_CONFIG})
+do
+       KERNEL_CONFIG[${cfg_ent}]="$cfg_ent"
+done
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index c0d129d7f430..f48231f16c2f 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -55,7 +55,7 @@ info()
 #
 archive_builtin()
 {
-       if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
+       if [ -n "${KERNEL_CONFIG[CONFIG_THIN_ARCHIVES]}" ]; then
                info AR built-in.o
                rm -f built-in.o;
                ${AR} rcsTP${KBUILD_ARFLAGS} built-in.o                 \
@@ -70,7 +70,7 @@ modpost_link()
 {
        local objects
 
-       if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
+       if [ -n "${KERNEL_CONFIG[CONFIG_THIN_ARCHIVES]}" ]; then
                objects="--whole-archive                                \
                        built-in.o                                      \
                        --no-whole-archive                              \
@@ -96,7 +96,7 @@ vmlinux_link()
        local objects
 
        if [ "${SRCARCH}" != "um" ]; then
-               if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
+               if [ -n "${KERNEL_CONFIG[CONFIG_THIN_ARCHIVES]}" ]; then
                        objects="--whole-archive                        \
                                built-in.o                              \
                                --no-whole-archive                      \
@@ -116,7 +116,7 @@ vmlinux_link()
                ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}             \
                        -T ${lds} ${objects}
        else
-               if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
+               if [ -n "${KERNEL_CONFIG[CONFIG_THIN_ARCHIVES]}" ]; then
                        objects="-Wl,--whole-archive                    \
                                built-in.o                              \
                                -Wl,--no-whole-archive                  \
@@ -226,14 +226,7 @@ if [ "$1" = "clean" ]; then
 fi
 
 # We need access to CONFIG_ symbols
-case "${KCONFIG_CONFIG}" in
-*/*)
-       . "${KCONFIG_CONFIG}"
-       ;;
-*)
-       # Force using a file from the current directory
-       . "./${KCONFIG_CONFIG}"
-esac
+. ${KBUILD_SRC}/scripts/importkconf.sh
 
 # Update version
 info GEN .version
@@ -259,7 +252,7 @@ ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
 
 kallsymso=""
 kallsyms_vmlinux=""
-if [ -n "${CONFIG_KALLSYMS}" ]; then
+if [ -n "${KERNEL_CONFIG[CONFIG_KALLSYMS]}" ]; then
 
        # kallsyms support
        # Generate section listing all symbols and add it into vmlinux
@@ -312,7 +305,7 @@ fi
 info LD vmlinux
 vmlinux_link "${kallsymso}" vmlinux
 
-if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
+if [ -n "${KERNEL_CONFIG[CONFIG_BUILDTIME_EXTABLE_SORT]}" ]; then
        info SORTEX vmlinux
        sortextable vmlinux
 fi
@@ -321,7 +314,7 @@ info SYSMAP System.map
 mksysmap vmlinux System.map
 
 # step a (see comment above)
-if [ -n "${CONFIG_KALLSYMS}" ]; then
+if [ -n "${KERNEL_CONFIG[CONFIG_KALLSYMS]}" ]; then
        mksysmap ${kallsyms_vmlinux} .tmp_System.map
 
        if ! cmp -s System.map .tmp_System.map; then
-- 
2.13.6

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