svn commit: r360169 - head/lib/libc/riscv/gen

[John Baldwin]

Author: jhb
Date: Tue Apr 21 17:40:23 2020
New Revision: 360169
URL: https://svnweb.freebsd.org/changeset/base/360169

Log:
  Check the magic value in longjmp() before calling sigprocmask().
  
  This avoids passing garbage to sigprocmask() if the jump buffer is
  invalid.
  
  Reviewed by:	mhorne
  Obtained from:	CheriBSD
  Sponsored by:	DARPA
  Differential Revision:	https://reviews.freebsd.org/D24483

Modified:
  head/lib/libc/riscv/gen/setjmp.S

Modified: head/lib/libc/riscv/gen/setjmp.S
==============================================================================
--- head/lib/libc/riscv/gen/setjmp.S	Tue Apr 21 17:38:07 2020	(r360168)
+++ head/lib/libc/riscv/gen/setjmp.S	Tue Apr 21 17:40:23 2020	(r360169)
@@ -100,6 +100,11 @@ ENTRY(setjmp)
 END(setjmp)
 
 ENTRY(longjmp)
+	/* Check the magic value */
+	ld	t0, 0(a0)
+	ld	t1, .Lmagic
+	bne	t0, t1, botch
+
 	addi	sp, sp, -(4 * 8)
 	sd	a0, (0 * 8)(sp)
 	sd	ra, (1 * 8)(sp)
@@ -115,11 +120,6 @@ ENTRY(longjmp)
 	ld	ra, (1 * 8)(sp)
 	ld	a0, (0 * 8)(sp)
 	addi	sp, sp, (4 * 8)
-
-	/* Check the magic value */
-	ld	t0, 0(a0)
-	ld	t1, .Lmagic
-	bne	t0, t1, botch
 
 	/* Restore the stack pointer */
 	ld	t0, 8(a0)