Check for valid stack frame in longjmp.

If longjmp restores the stack frame to an address which is beyond
the stack frame at the time of the longjmp call it would install
an uninitialized stack frame.  If compiled with _FORTIFY_SOURCE
defined, longjmp will now bail out in this situation.

4 files changed, 100 insertions, 1 deletions

diff --git a/sysdeps/i386/____longjmp_chk.S b/sysdeps/i386/____longjmp_chk.S
new file mode 100644
index 0000000..6cd7496
--- /dev/null
+++ b/sysdeps/i386/____longjmp_chk.S
@@ -0,0 +1,45 @@
+/* Copyright (C) 2001,2004,2005,2006,2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+	.section .rodata.str1.1,"aMS",@progbits,1
+	.type	longjmp_msg,@object
+longjmp_msg:
+	.string "longjmp causes uninitialized stack frame"
+	.size	longjmp_msg, .-longjmp_msg
+
+
+#define __longjmp ____longjmp_chk
+
+#ifdef PIC
+# define CALL_FAIL	movl	%ebx, %ecx;				      \
+			cfi_register(%ebx,%ecx);			      \
+			LOAD_PIC_REG (bx);				      \
+			leal	longjmp_msg@GOTOFF(%ebx), %eax;		      \
+			call	__GI___fortify_fail@PLT
+#else
+# define CALL_FAIL	movl	$longjmp_msg, %eax;			      \
+			call	__fortify_fail
+#endif
+
+#define CHECK_ESP(reg) \
+	cmpl	reg, %esp;						      \
+	jbe	.Lok;							      \
+	CALL_FAIL;							      \
+.Lok:
+
+#include "__longjmp.S"
diff --git a/sysdeps/i386/__longjmp.S b/sysdeps/i386/__longjmp.S
index 559d56b..15c9e55 100644
--- a/sysdeps/i386/__longjmp.S
+++ b/sysdeps/i386/__longjmp.S
@@ -1,5 +1,6 @@
 /* longjmp for i386.
-   Copyright (C) 1995-1998,2000,2002,2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 1995-1998,2000,2002,2005,2006,2009
+   Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -40,6 +41,9 @@ ENTRY (BP_SYM (__longjmp))
 	movl (JB_SP*4)(%eax), %ecx
 	PTR_DEMANGLE (%edx)
 	PTR_DEMANGLE (%ecx)
+# ifdef CHECK_ESP
+	CHECK_ESP (%ecx)
+# endif
 	cfi_def_cfa(%eax, 0)
 	cfi_register(%eip, %edx)
 	cfi_register(%esp, %ecx)
@@ -63,6 +67,11 @@ ENTRY (BP_SYM (__longjmp))
 	movl JBUF(%esp), %ecx	/* User's jmp_buf in %ecx.  */
 	CHECK_BOUNDS_BOTH_WIDE (%ecx, JBUF(%esp), $JB_SIZE)
 
+# ifdef CHECK_ESP
+	movl (JB_SP*4)(%ecx), %eax
+	CHECK_ESP (%eax)
+# endif
+
 	movl VAL(%esp), %eax	/* Second argument is return value.  */
 	/* Save the return address now.  */
 	movl (JB_PC*4)(%ecx), %edx
diff --git a/sysdeps/x86_64/____longjmp_chk.S b/sysdeps/x86_64/____longjmp_chk.S
new file mode 100644
index 0000000..030a0dc
--- /dev/null
+++ b/sysdeps/x86_64/____longjmp_chk.S
@@ -0,0 +1,42 @@
+/* Copyright (C) 2001,2004,2005,2006,2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+	.section .rodata.str1.1,"aMS",@progbits,1
+	.type	longjmp_msg,@object
+longjmp_msg:
+	.string "longjmp causes uninitialized stack frame"
+	.size	longjmp_msg, .-longjmp_msg
+
+
+#define __longjmp ____longjmp_chk
+
+#ifdef PIC
+# define CALL_FAIL	leaq	longjmp_msg(%rip), %rdi;		      \
+			call	__GI___fortify_fail
+#else
+# define CALL_FAIL	movq	$longjmp_msg, %rdi;			      \
+			call	__fortify_fail
+#endif
+
+#define CHECK_RSP(reg) \
+	cmpq	reg, %rsp;						      \
+	jbe	.Lok;							      \
+	CALL_FAIL;							      \
+.Lok:
+
+#include "__longjmp.S"
diff --git a/sysdeps/x86_64/__longjmp.S b/sysdeps/x86_64/__longjmp.S
index a68e7a8..7649e99 100644
--- a/sysdeps/x86_64/__longjmp.S
+++ b/sysdeps/x86_64/__longjmp.S
@@ -33,6 +33,9 @@ ENTRY(__longjmp)
 	PTR_DEMANGLE (%r9)
 	PTR_DEMANGLE (%rdx)
 #endif
+#ifdef CHECK_RSP
+	CHECK_RSP (%r8)
+#endif
 	/* We add unwind information for the target here.  */
 	cfi_def_cfa(%rdi, 0)
 	cfi_register(%rsp,%r8)