Commit d2f5d3fa authored by Thomas Gleixner's avatar Thomas Gleixner

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: 7ac87074 ("x86/vdso: Switch to generic vDSO implementation")
Reported-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Reported-by: default avatarPaul Bolle <pebolle@tiscali.nl>
Suggested-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20190728131648.879156507@linutronix.de
parent c60a32ea
...@@ -96,6 +96,8 @@ long clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) ...@@ -96,6 +96,8 @@ long clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
#else #else
#define VDSO_HAS_32BIT_FALLBACK 1
static __always_inline static __always_inline
long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) 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) ...@@ -113,6 +115,23 @@ long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
return ret; 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 static __always_inline
long gettimeofday_fallback(struct __kernel_old_timeval *_tv, long gettimeofday_fallback(struct __kernel_old_timeval *_tv,
struct timezone *_tz) struct timezone *_tz)
...@@ -148,6 +167,23 @@ clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) ...@@ -148,6 +167,23 @@ clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
return ret; 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 #endif
#ifdef CONFIG_PARAVIRT_CLOCK #ifdef CONFIG_PARAVIRT_CLOCK
......
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