From 222ca305c9fd39e5ed8104da25c09b2b79a516a8 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 10 Feb 2022 16:24:30 +0100 Subject: uaccess: fix integer overflow on access_ok() Three architectures check the end of a user access against the address limit without taking a possible overflow into account. Passing a negative length or another overflow in here returns success when it should not. Use the most common correct implementation here, which optimizes for a constant 'size' argument, and turns the common case into a single comparison. Cc: stable@vger.kernel.org Fixes: da551281947c ("csky: User access") Fixes: f663b60f5215 ("microblaze: Fix uaccess_ok macro") Fixes: 7567746e1c0d ("Hexagon: Add user access functions") Reported-by: David Laight Reviewed-by: Christoph Hellwig Signed-off-by: Arnd Bergmann --- arch/hexagon/include/asm/uaccess.h | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) (limited to 'arch/hexagon/include') diff --git a/arch/hexagon/include/asm/uaccess.h b/arch/hexagon/include/asm/uaccess.h index ef5bfef8d490..719ba3f3c45c 100644 --- a/arch/hexagon/include/asm/uaccess.h +++ b/arch/hexagon/include/asm/uaccess.h @@ -25,17 +25,17 @@ * Returns true (nonzero) if the memory block *may* be valid, false (zero) * if it is definitely invalid. * - * User address space in Hexagon, like x86, goes to 0xbfffffff, so the - * simple MSB-based tests used by MIPS won't work. Some further - * optimization is probably possible here, but for now, keep it - * reasonably simple and not *too* slow. After all, we've got the - * MMU for backup. */ +#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) -#define __access_ok(addr, size) \ - ((get_fs().seg == KERNEL_DS.seg) || \ - (((unsigned long)addr < get_fs().seg) && \ - (unsigned long)size < (get_fs().seg - (unsigned long)addr))) +static inline int __access_ok(unsigned long addr, unsigned long size) +{ + unsigned long limit = TASK_SIZE; + + return (size <= limit) && (addr <= (limit - size)); +} +#define __access_ok __access_ok /* * When a kernel-mode page fault is taken, the faulting instruction -- cgit v1.2.3