From 4f69594689992d76088f2b0af79cd91c40579f64 Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Fri, 1 May 2015 21:22:27 -0400
Subject: [PATCH] fix dangling pointers in x32 syscall timespec fixup code

the lifetime of compound literals is the block in which they appear.
the temporary struct __timespec_kernel objects created as compound
literals no longer existed at the time their addresses were passed to
the kernel.
---
 arch/x32/src/syscall_cp_fixup.c | 10 +++++++---
 arch/x32/syscall_arch.h         | 23 ++++++++++++++++-------
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/arch/x32/src/syscall_cp_fixup.c b/arch/x32/src/syscall_cp_fixup.c
index 07d39b52..deb01ee9 100644
--- a/arch/x32/src/syscall_cp_fixup.c
+++ b/arch/x32/src/syscall_cp_fixup.c
@@ -9,14 +9,18 @@ long __syscall_cp_internal(volatile void*, long long, long long, long long, long
 struct __timespec { long long tv_sec; long tv_nsec; };
 struct __timespec_kernel { long long tv_sec; long long tv_nsec; };
 #define __tsc(X) ((struct __timespec*)(unsigned long)(X))
-#define __fixup(X) do { if(X) X = (unsigned long) (&(struct __timespec_kernel) \
-                   { .tv_sec = __tsc(X)->tv_sec, .tv_nsec = __tsc(X)->tv_nsec}); } while(0)
+#define __fixup(X) do { if(X) { \
+	ts->tv_sec = __tsc(X)->tv_sec; \
+	ts->tv_nsec = __tsc(X)->tv_nsec; \
+	(X) = (unsigned long)ts; } } while(0)
 
 #ifdef SHARED
 __attribute__((__visibility__("hidden")))
 #endif
 long __syscall_cp_asm (volatile void * foo, long long n, long long a1, long long a2, long long a3,
-	                     long long a4, long long a5, long long a6) {
+	                     long long a4, long long a5, long long a6)
+{
+	struct __timespec_kernel ts[1];
 	switch (n) {
 	case SYS_mq_timedsend: case SYS_mq_timedreceive: case SYS_pselect6:
 		__fixup(a5);
diff --git a/arch/x32/syscall_arch.h b/arch/x32/syscall_arch.h
index af67fe3f..344da03c 100644
--- a/arch/x32/syscall_arch.h
+++ b/arch/x32/syscall_arch.h
@@ -6,8 +6,10 @@ typedef long long syscall_arg_t;
 struct __timespec { long long tv_sec; long tv_nsec; };
 struct __timespec_kernel { long long tv_sec; long long tv_nsec; };
 #define __tsc(X) ((struct __timespec*)(unsigned long)(X))
-#define __fixup(X) do { if(X) X = (unsigned long) (&(struct __timespec_kernel) \
-                   { .tv_sec = __tsc(X)->tv_sec, .tv_nsec = __tsc(X)->tv_nsec}); } while(0)
+#define __fixup(X) do { if(X) { \
+	ts->tv_sec = __tsc(X)->tv_sec; \
+	ts->tv_nsec = __tsc(X)->tv_nsec; \
+	(X) = (unsigned long)ts; } } while(0)
 #define __fixup_case_2 \
 	case SYS_nanosleep: \
 		__fixup(a1); break; \
@@ -17,10 +19,13 @@ struct __timespec_kernel { long long tv_sec; long long tv_nsec; };
 	case SYS_clock_nanosleep: case SYS_rt_sigtimedwait: case SYS_ppoll: \
 		__fixup(a3); break; \
 	case SYS_utimensat: \
-		if(a3) a3 = (unsigned long) ((struct __timespec_kernel[2]) { \
-		[0] = {.tv_sec = __tsc(a3)[0].tv_sec, .tv_nsec = __tsc(a3)[0].tv_nsec}, \
-		[1] = {.tv_sec = __tsc(a3)[1].tv_sec, .tv_nsec = __tsc(a3)[1].tv_nsec}, \
-		}); break;
+		if(a3) { \
+			ts[0].tv_sec = __tsc(a3)[0].tv_sec; \
+			ts[0].tv_nsec = __tsc(a3)[0].tv_nsec; \
+			ts[1].tv_sec = __tsc(a3)[1].tv_sec; \
+			ts[1].tv_nsec = __tsc(a3)[1].tv_nsec; \
+			a3 = (unsigned long)ts; \
+		} break;
 #define __fixup_case_4 \
 	case SYS_futex: \
 		if((a2 & (~128 /* FUTEX_PRIVATE_FLAG */)) == 0 /* FUTEX_WAIT */) __fixup(a4); break;
@@ -45,7 +50,7 @@ static __inline long __syscall1(long long n, long long a1)
 static __inline long __syscall2(long long n, long long a1, long long a2)
 {
 	unsigned long ret;
-	struct __timespec *ts2 = 0;
+	struct __timespec_kernel ts[1];
 	switch (n) {
 		__fixup_case_2;
 	}
@@ -57,6 +62,7 @@ static __inline long __syscall2(long long n, long long a1, long long a2)
 static __inline long __syscall3(long long n, long long a1, long long a2, long long a3)
 {
 	unsigned long ret;
+	struct __timespec_kernel ts[2];
 	switch (n) {
 		__fixup_case_2;
 		__fixup_case_3;
@@ -71,6 +77,7 @@ static __inline long __syscall4(long long n, long long a1, long long a2, long lo
 {
 	unsigned long ret;
 	register long long a4 __asm__("r10") = a4_;
+	struct __timespec_kernel ts[2];
 	switch (n) {
 		__fixup_case_2;
 		__fixup_case_3;
@@ -87,6 +94,7 @@ static __inline long __syscall5(long long n, long long a1, long long a2, long lo
 	unsigned long ret;
 	register long long a4 __asm__("r10") = a4_;
 	register long long a5 __asm__("r8") = a5_;
+	struct __timespec_kernel ts[2];
 	switch (n) {
 		__fixup_case_2;
 		__fixup_case_3;
@@ -105,6 +113,7 @@ static __inline long __syscall6(long long n, long long a1, long long a2, long lo
 	register long long a4 __asm__("r10") = a4_;
 	register long long a5 __asm__("r8") = a5_;
 	register long long a6 __asm__("r9") = a6_;
+	struct __timespec_kernel ts[2];
 	switch (n) {
 		__fixup_case_2;
 		__fixup_case_3;