From 02f6f0e83bfa018eee86909e3a2961e7a2648884 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Wed, 13 Nov 2024 09:18:37 +0100
Subject: [PATCH] musl: Add unwinding protection in clone() implementations.

Whatever was in the frame pointer register prior to clone() will no longer be
valid in the child process, so zero it to protect FP-based unwinders. This is
just an extension of what was already done for i386 and x86_64. Only applied
to architectures where the _start() code also zeroes the frame pointer.
---
 lib/libc/musl/src/thread/aarch64/clone.s     | 3 ++-
 lib/libc/musl/src/thread/arm/clone.s         | 3 ++-
 lib/libc/musl/src/thread/loongarch64/clone.s | 1 +
 lib/libc/musl/src/thread/m68k/clone.s        | 3 ++-
 lib/libc/musl/src/thread/microblaze/clone.s  | 3 ++-
 lib/libc/musl/src/thread/mips/clone.s        | 3 ++-
 lib/libc/musl/src/thread/mips64/clone.s      | 3 ++-
 lib/libc/musl/src/thread/mipsn32/clone.s     | 3 ++-
 lib/libc/musl/src/thread/or1k/clone.s        | 3 ++-
 9 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/lib/libc/musl/src/thread/aarch64/clone.s b/lib/libc/musl/src/thread/aarch64/clone.s
index e3c83395cad2..9ac272bde3e6 100644
--- a/lib/libc/musl/src/thread/aarch64/clone.s
+++ b/lib/libc/musl/src/thread/aarch64/clone.s
@@ -24,7 +24,8 @@ __clone:
 	// parent
 	ret
 	// child
-1:	ldp x1,x0,[sp],#16
+1:	mov fp, 0
+	ldp x1,x0,[sp],#16
 	blr x1
 	mov x8,#93 // SYS_exit
 	svc #0
diff --git a/lib/libc/musl/src/thread/arm/clone.s b/lib/libc/musl/src/thread/arm/clone.s
index bb0965dafe82..4ff0c0e88b1d 100644
--- a/lib/libc/musl/src/thread/arm/clone.s
+++ b/lib/libc/musl/src/thread/arm/clone.s
@@ -19,7 +19,8 @@ __clone:
 	ldmfd sp!,{r4,r5,r6,r7}
 	bx lr
 
-1:	mov r0,r6
+1:	mov fp,#0
+	mov r0,r6
 	bl 3f
 2:	mov r7,#1
 	svc 0
diff --git a/lib/libc/musl/src/thread/loongarch64/clone.s b/lib/libc/musl/src/thread/loongarch64/clone.s
index a165b365a38e..cb4aacfc6d89 100644
--- a/lib/libc/musl/src/thread/loongarch64/clone.s
+++ b/lib/libc/musl/src/thread/loongarch64/clone.s
@@ -22,6 +22,7 @@ __clone:
 	beqz    $a0, 1f         # whether child process
 	jirl    $zero, $ra, 0   # parent process return
 1:
+	move    $fp, $zero
 	ld.d    $t8, $sp, 0     # function pointer
 	ld.d    $a0, $sp, 8     # argument pointer
 	jirl    $ra, $t8, 0     # call the user's function
diff --git a/lib/libc/musl/src/thread/m68k/clone.s b/lib/libc/musl/src/thread/m68k/clone.s
index f6dfa06f49da..42ec19f7242a 100644
--- a/lib/libc/musl/src/thread/m68k/clone.s
+++ b/lib/libc/musl/src/thread/m68k/clone.s
@@ -18,7 +18,8 @@ __clone:
 	beq 1f
 	movem.l (%sp)+,%d2-%d5
 	rts
-1:	move.l %a1,-(%sp)
+1:	suba.l %%fp,%%fp
+	move.l %a1,-(%sp)
 	jsr (%a0)
 	move.l #1,%d0
 	trap #0
diff --git a/lib/libc/musl/src/thread/microblaze/clone.s b/lib/libc/musl/src/thread/microblaze/clone.s
index b68cc5fc2213..64e3f0743f6c 100644
--- a/lib/libc/musl/src/thread/microblaze/clone.s
+++ b/lib/libc/musl/src/thread/microblaze/clone.s
@@ -22,7 +22,8 @@ __clone:
 	rtsd    r15, 8
 	nop
 
-1:	lwi     r3, r1, 0
+1:	add     r19, r0, r0
+	lwi     r3, r1, 0
 	lwi     r5, r1, 4
 	brald   r15, r3
 	nop
diff --git a/lib/libc/musl/src/thread/mips/clone.s b/lib/libc/musl/src/thread/mips/clone.s
index 0446338568f0..229b987e9691 100644
--- a/lib/libc/musl/src/thread/mips/clone.s
+++ b/lib/libc/musl/src/thread/mips/clone.s
@@ -27,7 +27,8 @@ __clone:
 	addu $sp, $sp, 16
 	jr $ra
 	nop
-1:	lw $25, 0($sp)
+1:	move $fp, $0
+	lw $25, 0($sp)
 	lw $4, 4($sp)
 	jalr $25
 	nop
diff --git a/lib/libc/musl/src/thread/mips64/clone.s b/lib/libc/musl/src/thread/mips64/clone.s
index 2d86899a1daa..8de3db6c4e36 100644
--- a/lib/libc/musl/src/thread/mips64/clone.s
+++ b/lib/libc/musl/src/thread/mips64/clone.s
@@ -25,7 +25,8 @@ __clone:
 	nop
 	jr	$ra
 	nop
-1:	ld	$25, 0($sp)	# function pointer
+1:	move	$fp, $0
+	ld	$25, 0($sp)	# function pointer
 	ld	$4, 8($sp)	# argument pointer
 	jalr	$25		# call the user's function
 	nop
diff --git a/lib/libc/musl/src/thread/mipsn32/clone.s b/lib/libc/musl/src/thread/mipsn32/clone.s
index 4d3c8c7a2502..9571231a62cf 100644
--- a/lib/libc/musl/src/thread/mipsn32/clone.s
+++ b/lib/libc/musl/src/thread/mipsn32/clone.s
@@ -25,7 +25,8 @@ __clone:
 	nop
 	jr	$ra
 	nop
-1:	lw	$25, 0($sp)	# function pointer
+1:	move	$fp, $0
+	lw	$25, 0($sp)	# function pointer
 	lw	$4, 4($sp)	# argument pointer
 	jalr	$25		# call the user's function
 	nop
diff --git a/lib/libc/musl/src/thread/or1k/clone.s b/lib/libc/musl/src/thread/or1k/clone.s
index 2473ac204036..05c55c6982dc 100644
--- a/lib/libc/musl/src/thread/or1k/clone.s
+++ b/lib/libc/musl/src/thread/or1k/clone.s
@@ -23,7 +23,8 @@ __clone:
 	l.jr	r9
 	 l.nop
 
-1:	l.lwz	r11, 0(r1)
+1:	l.ori	r2, r0, 0
+	l.lwz	r11, 0(r1)
 	l.jalr	r11
 	 l.lwz	r3, 4(r1)