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UPSTREAM: x86/vdso/32: Use 32bit syscall fallback

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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: 7ac8707479 ("x86/vdso: Switch to generic vDSO implementation")
Reported-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20190728131648.879156507@linutronix.de
(cherry picked from commit d2f5d3fa26)
Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Bug: 154668398
Change-Id: I8b1b562bab3cdcb78d0d229bfeebe739f1992437
This commit is contained in:
Thomas Gleixner
2019-07-28 15:12:55 +02:00
committed by Alistair Delva
parent 46b8016ba3
commit 41423d05ab
1 changed files with 36 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
arch/x86/include/asm/vdso/gettimeofday.h
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@@ -97,6 +97,8 @@ 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)
{
@@ -114,6 +116,23 @@ 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)
@@ -149,6 +168,23 @@ 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