From d2f5d3fa26196183adb44a413c44caa9872275b4 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 28 Jul 2019 15:12:55 +0200 Subject: x86/vdso/32: Use 32bit syscall fallback The generic VDSO implementation uses the Y2038 safe clock_gettime64() and clock_getres_time64() syscalls as fallback for 32bit VDSO. This breaks seccomp setups because these syscalls might be not (yet) allowed. Implement the 32bit variants which use the legacy syscalls and select the variant in the core library. The 64bit time variants are not removed because they are required for the time64 based vdso accessors. Fixes: 7ac870747988 ("x86/vdso: Switch to generic vDSO implementation") Reported-by: Sean Christopherson Reported-by: Paul Bolle Suggested-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Reviewed-by: Vincenzo Frascino Reviewed-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20190728131648.879156507@linutronix.de --- arch/x86/include/asm/vdso/gettimeofday.h | 36 ++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'arch') diff --git a/arch/x86/include/asm/vdso/gettimeofday.h b/arch/x86/include/asm/vdso/gettimeofday.h index ae91429129a6..ba71a63cdac4 100644 --- a/arch/x86/include/asm/vdso/gettimeofday.h +++ b/arch/x86/include/asm/vdso/gettimeofday.h @@ -96,6 +96,8 @@ long clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) #else +#define VDSO_HAS_32BIT_FALLBACK 1 + static __always_inline long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) { @@ -113,6 +115,23 @@ long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) return ret; } +static __always_inline +long clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts) +{ + long ret; + + asm ( + "mov %%ebx, %%edx \n" + "mov %[clock], %%ebx \n" + "call __kernel_vsyscall \n" + "mov %%edx, %%ebx \n" + : "=a" (ret), "=m" (*_ts) + : "0" (__NR_clock_gettime), [clock] "g" (_clkid), "c" (_ts) + : "edx"); + + return ret; +} + static __always_inline long gettimeofday_fallback(struct __kernel_old_timeval *_tv, struct timezone *_tz) @@ -148,6 +167,23 @@ clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) return ret; } +static __always_inline +long clock_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts) +{ + long ret; + + asm ( + "mov %%ebx, %%edx \n" + "mov %[clock], %%ebx \n" + "call __kernel_vsyscall \n" + "mov %%edx, %%ebx \n" + : "=a" (ret), "=m" (*_ts) + : "0" (__NR_clock_getres), [clock] "g" (_clkid), "c" (_ts) + : "edx"); + + return ret; +} + #endif #ifdef CONFIG_PARAVIRT_CLOCK -- cgit v1.2.3-58-ga151 From 33a58980ff3cc5dbf0bb1b325746ac69223eda0b Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 28 Jul 2019 15:12:56 +0200 Subject: arm64: compat: vdso: Use legacy syscalls as fallback The generic VDSO implementation uses the Y2038 safe clock_gettime64() and clock_getres_time64() syscalls as fallback for 32bit VDSO. This breaks seccomp setups because these syscalls might be not (yet) allowed. Implement the 32bit variants which use the legacy syscalls and select the variant in the core library. The 64bit time variants are not removed because they are required for the time64 based vdso accessors. Fixes: 00b26474c2f1 ("lib/vdso: Provide generic VDSO implementation") Reported-by: Sean Christopherson Reported-by: Paul Bolle Suggested-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Tested-by: Vincenzo Frascino Reviewed-by: Vincenzo Frascino Link: https://lkml.kernel.org/r/20190728131648.971361611@linutronix.de --- arch/arm64/include/asm/vdso/compat_gettimeofday.h | 40 +++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'arch') diff --git a/arch/arm64/include/asm/vdso/compat_gettimeofday.h b/arch/arm64/include/asm/vdso/compat_gettimeofday.h index f4812777f5c5..c50ee1b7d5cd 100644 --- a/arch/arm64/include/asm/vdso/compat_gettimeofday.h +++ b/arch/arm64/include/asm/vdso/compat_gettimeofday.h @@ -16,6 +16,8 @@ #define VDSO_HAS_CLOCK_GETRES 1 +#define VDSO_HAS_32BIT_FALLBACK 1 + static __always_inline int gettimeofday_fallback(struct __kernel_old_timeval *_tv, struct timezone *_tz) @@ -51,6 +53,23 @@ long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) return ret; } +static __always_inline +long clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts) +{ + register struct old_timespec32 *ts asm("r1") = _ts; + register clockid_t clkid asm("r0") = _clkid; + register long ret asm ("r0"); + register long nr asm("r7") = __NR_compat_clock_gettime; + + asm volatile( + " swi #0\n" + : "=r" (ret) + : "r" (clkid), "r" (ts), "r" (nr) + : "memory"); + + return ret; +} + static __always_inline int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) { @@ -72,6 +91,27 @@ int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) return ret; } +static __always_inline +int clock_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts) +{ + register struct old_timespec32 *ts asm("r1") = _ts; + register clockid_t clkid asm("r0") = _clkid; + register long ret asm ("r0"); + register long nr asm("r7") = __NR_compat_clock_getres; + + /* The checks below are required for ABI consistency with arm */ + if ((_clkid >= MAX_CLOCKS) && (_ts == NULL)) + return -EINVAL; + + asm volatile( + " swi #0\n" + : "=r" (ret) + : "r" (clkid), "r" (ts), "r" (nr) + : "memory"); + + return ret; +} + static __always_inline u64 __arch_get_hw_counter(s32 clock_mode) { u64 res; -- cgit v1.2.3-58-ga151