[PATCH 1/3] x86: vdso: Always reject undefined references in during linking

From: Thomas Weißschuh
Date: Fri Oct 11 2024 - 05:19:13 EST


Instead of using a custom script to detect and fail on undefined
references, use --no-undefined for all VDSO linker invocations.

Drop the now unused checkundef.sh script.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
arch/x86/entry/vdso/Makefile | 7 +++----
arch/x86/entry/vdso/checkundef.sh | 10 ----------
2 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index c9216ac4fb1eb8c1e5bc5e33b41e9e40c7924cbf..99de18d88bc39f8f83f35e554028efd0a76fccec 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -32,7 +32,7 @@ targets += $(foreach x, 64 x32 32, vdso-image-$(x).c vdso$(x).so vdso$(x).so.dbg

CPPFLAGS_vdso.lds += -P -C

-VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \
+VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 \
-z max-page-size=4096

$(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
@@ -151,10 +151,9 @@ $(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE
quiet_cmd_vdso = VDSO $@
cmd_vdso = $(LD) -o $@ \
$(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
- -T $(filter %.lds,$^) $(filter %.o,$^) && \
- sh $(src)/checkundef.sh '$(NM)' '$@'
+ -T $(filter %.lds,$^) $(filter %.o,$^)

-VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 \
+VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 --no-undefined \
$(call ld-option, --eh-frame-hdr) -Bsymbolic -z noexecstack

quiet_cmd_vdso_and_check = VDSO $@
diff --git a/arch/x86/entry/vdso/checkundef.sh b/arch/x86/entry/vdso/checkundef.sh
deleted file mode 100755
index 7ee90a9b549da32c9c12d694215b89d08645574c..0000000000000000000000000000000000000000
--- a/arch/x86/entry/vdso/checkundef.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/bin/sh
-nm="$1"
-file="$2"
-$nm "$file" | grep '^ *U' > /dev/null 2>&1
-if [ $? -eq 1 ]; then
- exit 0
-else
- echo "$file: undefined symbols found" >&2
- exit 1
-fi

--
2.47.0