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Subject[PATCH v4 18/26] arm64: vdso32: Replace TASK_SIZE_32 check in vgettimeofday
Date
For ABI compatibility with arm32, the compat vDSO layer on arm64 needs
to return -EINVAL when UINTPTR_MAX is passed as argument to the
clock_get* functions.

Replace TASK_SIZE_32 with a more semantically correct formula that checks
for wrapping around 0.

Note: This will allow to not define TASK_SIZE_32 for the vdso headers in a
future patch that will introduce asm/vdso/processor.h on arm64.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
arch/arm64/kernel/vdso32/vgettimeofday.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
index 54fc1c2ce93f..91138077b073 100644
--- a/arch/arm64/kernel/vdso32/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -8,11 +8,14 @@
#include <linux/time.h>
#include <linux/types.h>

+#define VALID_CLOCK_ID(x) \
+ ((x >= 0) && (x < VDSO_BASES))
+
int __vdso_clock_gettime(clockid_t clock,
struct old_timespec32 *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;

return __cvdso_clock_gettime32(clock, ts);
@@ -22,7 +25,7 @@ int __vdso_clock_gettime64(clockid_t clock,
struct __kernel_timespec *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;

return __cvdso_clock_gettime(clock, ts);
@@ -38,9 +41,12 @@ int __vdso_clock_getres(clockid_t clock_id,
struct old_timespec32 *res)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)res >= TASK_SIZE_32)
+ if ((u32)res > UINTPTR_MAX - sizeof(res) + 1)
return -EFAULT;

+ if (!VALID_CLOCK_ID(clock_id) && res == NULL)
+ return -EINVAL;
+
return __cvdso_clock_getres_time32(clock_id, res);
}

--
2.25.1
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