Messages in this thread | | | Subject | Re: [patch 4/5] x86/vdso/32: Use 32bit syscall fallback | From | Vincenzo Frascino <> | Date | Mon, 29 Jul 2019 12:23:03 +0100 |
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On 28/07/2019 14:12, Thomas Gleixner wrote: > 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. >
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Reported-by: Sean Christopherson <sean.j.christopherson@intel.com> > Reported-by: Paul Bolle <pebolle@tiscali.nl> > Suggested-by: Andy Lutomirski <luto@kernel.org> > Fixes: 7ac870747988 ("x86/vdso: Switch to generic vDSO implementation") > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > --- > arch/x86/include/asm/vdso/gettimeofday.h | 36 +++++++++++++++++++++++++++++++ > 1 file changed, 36 insertions(+) > > --- 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 _cl > > #else > > +#define VDSO_HAS_32BIT_FALLBACK 1 > + > static __always_inline > long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts) > { > @@ -114,6 +116,23 @@ long clock_gettime_fallback(clockid_t _c > } > > 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) > { > @@ -146,6 +165,23 @@ clock_getres_fallback(clockid_t _clkid, > : "edx"); > > 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 > >
-- Regards, Vincenzo
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