klibc - Jul 2020 - [klibc:master] arch: Explicitly disable or enable executable stacks

Commit-ID:  27ad55131385821dfe85b0320f4d6ba8861ab7e5
Gitweb:    
http://git.kernel.org/?p=libs/klibc/klibc.git;a=commit;h=27ad55131385821dfe85b0320f4d6ba8861ab7e5
Author:     Ben Hutchings <ben at decadent.org.uk>
AuthorDate: Wed, 29 Apr 2020 22:56:59 +0100
Committer:  Ben Hutchings <ben at decadent.org.uk>
CommitDate: Sat, 25 Jul 2020 17:33:29 +0100

[klibc] arch: Explicitly disable or enable executable stacks

For each architecture (except cris, which is obsolete) set
KLIBCEXECSTACK to 'y' or 'n', and comment on the kernel's
signal
return implementation.

Signed-off-by: Ben Hutchings <ben at decadent.org.uk>

---
 usr/klibc/arch/alpha/MCONFIG   | 4 ++++
 usr/klibc/arch/arm/MCONFIG     | 3 +++
 usr/klibc/arch/arm64/MCONFIG   | 3 +++
 usr/klibc/arch/i386/MCONFIG    | 3 +++
 usr/klibc/arch/ia64/MCONFIG    | 3 +++
 usr/klibc/arch/m68k/MCONFIG    | 4 ++++
 usr/klibc/arch/mips/MCONFIG    | 3 +++
 usr/klibc/arch/mips64/MCONFIG  | 3 +++
 usr/klibc/arch/parisc/MCONFIG  | 3 +++
 usr/klibc/arch/ppc/MCONFIG     | 3 +++
 usr/klibc/arch/ppc64/MCONFIG   | 3 +++
 usr/klibc/arch/riscv64/MCONFIG | 3 +++
 usr/klibc/arch/s390/MCONFIG    | 4 ++++
 usr/klibc/arch/sh/MCONFIG      | 3 +++
 usr/klibc/arch/sparc/MCONFIG   | 4 ++++
 usr/klibc/arch/sparc64/MCONFIG | 3 +++
 usr/klibc/arch/x86_64/MCONFIG  | 3 +++
 17 files changed, 55 insertions(+)

diff --git a/usr/klibc/arch/alpha/MCONFIG b/usr/klibc/arch/alpha/MCONFIG
index ad11372f..072adb85 100644
--- a/usr/klibc/arch/alpha/MCONFIG
+++ b/usr/klibc/arch/alpha/MCONFIG
@@ -14,3 +14,7 @@ KLIBCBITSIZE  = 64
 # 7 GB - normal binaries start at 4.5 GB, and the stack is below
 # the binary.
 KLIBCSHAREDFLAGS	= -Ttext-segment 0x1c0000000
+
+# Kernel uses stack trampoline for signal return unless we set
+# sa_restorer
+KLIBCEXECSTACK := y
diff --git a/usr/klibc/arch/arm/MCONFIG b/usr/klibc/arch/arm/MCONFIG
index 8a7096b8..ae407cb9 100644
--- a/usr/klibc/arch/arm/MCONFIG
+++ b/usr/klibc/arch/arm/MCONFIG
@@ -33,3 +33,6 @@ else
 KLIBCREQFLAGS += -mabi=apcs-gnu -mno-thumb-interwork
 endif
 endif
+
+# Kernel uses dedicated page or vDSO for signal return since 2.6.13
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/arm64/MCONFIG b/usr/klibc/arch/arm64/MCONFIG
index 6d22847e..e31ffea7 100644
--- a/usr/klibc/arch/arm64/MCONFIG
+++ b/usr/klibc/arch/arm64/MCONFIG
@@ -21,3 +21,6 @@ KLIBCREQFLAGS += -fno-exceptions -mgeneral-regs-only
 # On arm64, binaries are normally loaded at 4MB. Place klibc.so
 # a little before that at 2MB to prevent overlap.
 KLIBCSHAREDFLAGS = -Ttext-segment 0x0200000
+
+# Kernel has never used stack trampolines
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/i386/MCONFIG b/usr/klibc/arch/i386/MCONFIG
index 07046695..c7d3fccd 100644
--- a/usr/klibc/arch/i386/MCONFIG
+++ b/usr/klibc/arch/i386/MCONFIG
@@ -31,3 +31,6 @@ KLIBCBITSIZE  = 32
 # calls, and work on the memory models for this architecture
 # 96 MB - normal binaries start at 128 MB
 KLIBCSHAREDFLAGS	= -Ttext-segment 0x06000000
+
+# Kernel uses dedicated page or vDSO for signal return since 2.5.55
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/ia64/MCONFIG b/usr/klibc/arch/ia64/MCONFIG
index d12c9bf2..f2a25395 100644
--- a/usr/klibc/arch/ia64/MCONFIG
+++ b/usr/klibc/arch/ia64/MCONFIG
@@ -12,3 +12,6 @@ KLIBCOPTFLAGS += -Os
 KLIBCBITSIZE  = 64
 
 KLIBCSHAREDFLAGS = -T $(src)/arch/$(KLIBCARCH)/klibc.ld
+
+# Kernel has never used stack trampolines
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/m68k/MCONFIG b/usr/klibc/arch/m68k/MCONFIG
index 3f4bdae6..b57714e4 100644
--- a/usr/klibc/arch/m68k/MCONFIG
+++ b/usr/klibc/arch/m68k/MCONFIG
@@ -17,3 +17,7 @@ KLIBCBITSIZE  = 32
 # script right.  Not sure if there is a fundamental reason
 # to not duck below the halfway point...
 KLIBCSHAREDFLAGS        = -Ttext-segment 0xb0000000
+
+# Kernel uses stack trampoline for signal return.  Also m68k
+# page tables do not have an execute permission bit.
+KLIBCEXECSTACK := y
diff --git a/usr/klibc/arch/mips/MCONFIG b/usr/klibc/arch/mips/MCONFIG
index 7ad65232..7bf65a50 100644
--- a/usr/klibc/arch/mips/MCONFIG
+++ b/usr/klibc/arch/mips/MCONFIG
@@ -18,3 +18,6 @@ KLIBCBITSIZE      = 32
 #
 # Use -Ttext-segment so that the special .MIPS* sections are moved as well.
 KLIBCSHAREDFLAGS     = -Ttext-segment 0x00200000
+
+# Kernel uses vDSO for signal return since 2.6.34
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/mips64/MCONFIG b/usr/klibc/arch/mips64/MCONFIG
index 6a4b41b2..94b825a6 100644
--- a/usr/klibc/arch/mips64/MCONFIG
+++ b/usr/klibc/arch/mips64/MCONFIG
@@ -21,3 +21,6 @@ KLIBCBITSIZE  = 64
 #
 # Use -Ttext-segment so that the special .MIPS* sections are moved as well.
 KLIBCSHAREDFLAGS     = -Ttext-segment 0x12FE00000
+
+# Kernel uses vDSO for signal return since 2.6.34
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/parisc/MCONFIG b/usr/klibc/arch/parisc/MCONFIG
index 3472df67..1f53555e 100644
--- a/usr/klibc/arch/parisc/MCONFIG
+++ b/usr/klibc/arch/parisc/MCONFIG
@@ -10,3 +10,6 @@
 KLIBCOPTFLAGS += -Os -fomit-frame-pointer
 KLIBCBITSIZE  = 32
 KLIBCSHAREDFLAGS	= -Ttext-segment 0x40001000
+
+# Kernel uses stack trampoline for signal return
+KLIBCEXECSTACK := y
diff --git a/usr/klibc/arch/ppc/MCONFIG b/usr/klibc/arch/ppc/MCONFIG
index 8220f6b9..d8a0c108 100644
--- a/usr/klibc/arch/ppc/MCONFIG
+++ b/usr/klibc/arch/ppc/MCONFIG
@@ -24,3 +24,6 @@ KLIBCSHAREDFLAGS     = -Ttext-segment 0x0f800000
 
 # The asm include files live in asm-powerpc
 KLIBCASMARCH	= powerpc
+
+# Kernel uses vDSO for signal return since 2.6.12 (compat) or 2.6.15 (native)
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/ppc64/MCONFIG b/usr/klibc/arch/ppc64/MCONFIG
index 0315110c..530a07a0 100644
--- a/usr/klibc/arch/ppc64/MCONFIG
+++ b/usr/klibc/arch/ppc64/MCONFIG
@@ -22,3 +22,6 @@ KLIBCSHAREDFLAGS     = -Ttext-segment 0x0f000000
 
 # The asm include files live in asm-powerpc
 KLIBCASMARCH	= powerpc
+
+# Kernel uses vDSO for signal return since 2.6.12
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/riscv64/MCONFIG b/usr/klibc/arch/riscv64/MCONFIG
index 61681509..35df1f5f 100644
--- a/usr/klibc/arch/riscv64/MCONFIG
+++ b/usr/klibc/arch/riscv64/MCONFIG
@@ -18,3 +18,6 @@ KLIBCBITSIZE      = 64
 
 # Normal binaries start at 64 KB, so start the libary at 2 MB.
 KLIBCSHAREDFLAGS  =-Ttext-segment 0x00200000
+
+# Kernel has never used stack trampolines
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/s390/MCONFIG b/usr/klibc/arch/s390/MCONFIG
index 637f5aa6..c36acd7a 100644
--- a/usr/klibc/arch/s390/MCONFIG
+++ b/usr/klibc/arch/s390/MCONFIG
@@ -21,3 +21,7 @@ endif
 
 KLIBCASMARCH		= s390
 KLIBCSHAREDFLAGS	= -Ttext-segment 0x40000000
+
+# Kernel uses stack trampoline for signal return unless we set
+# sa_restorer
+KLIBCEXECSTACK := y
diff --git a/usr/klibc/arch/sh/MCONFIG b/usr/klibc/arch/sh/MCONFIG
index 2facf7cb..8421bbf9 100644
--- a/usr/klibc/arch/sh/MCONFIG
+++ b/usr/klibc/arch/sh/MCONFIG
@@ -15,3 +15,6 @@ KLIBCBITSIZE      = 32
 # calls, and work on the memory models for this architecture
 # 2 MB -- the normal starting point for text is 4 MB.
 KLIBCSHAREDFLAGS	= -Ttext-segment 0x00200000
+
+# Kernel uses vDSO for signal return since 2.6.19
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/sparc/MCONFIG b/usr/klibc/arch/sparc/MCONFIG
index 0623fdc2..cabc7cd4 100644
--- a/usr/klibc/arch/sparc/MCONFIG
+++ b/usr/klibc/arch/sparc/MCONFIG
@@ -17,3 +17,7 @@ KLIBCARCHREQFLAGS	+= -D__sparc32__
 # Normal binaries start at 64K; the linker wants 64K alignment,
 # and call instructions have a 30-bit signed offset, << 2.
 KLIBCSHAREDFLAGS	 = -Ttext-segment 0x40000000
+
+# Kernel uses stack trampoline for signal return unless we set
+# sa_restorer
+KLIBCEXECSTACK := y
diff --git a/usr/klibc/arch/sparc64/MCONFIG b/usr/klibc/arch/sparc64/MCONFIG
index c8339855..6f5dfbe9 100644
--- a/usr/klibc/arch/sparc64/MCONFIG
+++ b/usr/klibc/arch/sparc64/MCONFIG
@@ -19,3 +19,6 @@ KLIBCLDFLAGS      = -m elf64_sparc
 # Normal binaries start at 1 MB; the linker wants 1 MB alignment,
 # and call instructions have a 30-bit signed offset, << 2.
 KLIBCSHAREDFLAGS	= -Ttext-segment 0x80000000
+
+# Kernel has never used stack trampolines
+KLIBCEXECSTACK := n
diff --git a/usr/klibc/arch/x86_64/MCONFIG b/usr/klibc/arch/x86_64/MCONFIG
index c5f2fa26..1f5f99c7 100644
--- a/usr/klibc/arch/x86_64/MCONFIG
+++ b/usr/klibc/arch/x86_64/MCONFIG
@@ -36,3 +36,6 @@ KLIBCLDFLAGS      = -m elf_x86_64
 # in a broken layout with binutils 2.30.  Since there's no
 # architectural page size betwen 4 KB and 2MB, set it to 4 KB.
 KLIBCSHAREDFLAGS     = -Ttext-segment 0x00200000 -z max-page-size=0x1000
+
+# Kernel has never used stack trampolines
+KLIBCEXECSTACK := n