[hurd,commited] hurd: Fix longjmp early in initialization

Message ID 20200718131152.2037868-1-samuel.thibault@ens-lyon.org
State New
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  • [hurd,commited] hurd: Fix longjmp early in initialization
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Commit Message

Samuel Thibault July 18, 2020, 1:11 p.m.
When e.g. an LD_PRELOAD fails, _dl_signal_exception/error longjmps, but TLS
is not initialized yet, let along signal state.  We thus mustn't look at
them within __longjmp.

* sysdeps/mach/hurd/i386/____longjmp_chk.S,__longjmp.S: Check for
initialized value of %gs, and that sigstate is non-NULL.
---
 sysdeps/mach/hurd/i386/____longjmp_chk.S | 9 ++++++++-
 sysdeps/mach/hurd/i386/__longjmp.S       | 9 ++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)

-- 
2.27.0

Patch

diff --git a/sysdeps/mach/hurd/i386/____longjmp_chk.S b/sysdeps/mach/hurd/i386/____longjmp_chk.S
index 4d3a331728..5131386c60 100644
--- a/sysdeps/mach/hurd/i386/____longjmp_chk.S
+++ b/sysdeps/mach/hurd/i386/____longjmp_chk.S
@@ -60,7 +60,14 @@  ENTRY (____longjmp_chk)
 	PTR_DEMANGLE (%ecx)
 #endif
 
-	movl	%gs:SIGSTATE_OFFSET,%edi
+	movw	%ds, %si
+	movw	%gs, %di
+	cmpw	%si, %di
+	jz	.Lok		/* TLS not initialized yet */
+
+	movl	%gs:SIGSTATE_OFFSET, %edi
+	testl	%edi, %edi
+	jnz	.Lok		/* sigstate not initialized yet */
 
 	testl	$SS_ONSTACK, (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%edi)
 	jnz	.Lonstack
diff --git a/sysdeps/mach/hurd/i386/__longjmp.S b/sysdeps/mach/hurd/i386/__longjmp.S
index d123c214c9..73bbff9826 100644
--- a/sysdeps/mach/hurd/i386/__longjmp.S
+++ b/sysdeps/mach/hurd/i386/__longjmp.S
@@ -38,7 +38,14 @@  ENTRY (__longjmp)
 	PTR_DEMANGLE (%ecx)
 #endif
 
-	movl	%gs:SIGSTATE_OFFSET,%edi
+	movw	%ds, %si
+	movw	%gs, %di
+	cmpw	%si, %di
+	jz	.Lok		/* TLS not initialized yet */
+
+	movl	%gs:SIGSTATE_OFFSET, %edi
+	testl	%edi, %edi
+	jnz	.Lok		/* sigstate not initialized yet */
 
 	testl	$SS_ONSTACK, (HURD_SIGSTATE__SIGALTSTACK__OFFSET + SIGALTSTACK__SS_FLAGS__OFFSET)(%edi)
 	jz	.Lok