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/microblaze/include/asm/uaccess.h | 19 ++++--------------- 1 file changed, 4 insertions(+), 15 deletions(-) (limited to 'arch/microblaze/include') diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h index d2a8ef9f8978..5b6e0e7788f4 100644 --- a/arch/microblaze/include/asm/uaccess.h +++ b/arch/microblaze/include/asm/uaccess.h @@ -39,24 +39,13 @@ # define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -static inline int access_ok(const void __user *addr, unsigned long size) +static inline int __access_ok(unsigned long addr, unsigned long size) { - if (!size) - goto ok; + unsigned long limit = user_addr_max(); - if ((get_fs().seg < ((unsigned long)addr)) || - (get_fs().seg < ((unsigned long)addr + size - 1))) { - pr_devel("ACCESS fail at 0x%08x (size 0x%x), seg 0x%08x\n", - (__force u32)addr, (u32)size, - (u32)get_fs().seg); - return 0; - } -ok: - pr_devel("ACCESS OK at 0x%08x (size 0x%x), seg 0x%08x\n", - (__force u32)addr, (u32)size, - (u32)get_fs().seg); - return 1; + return (size <= limit) && (addr <= (limit - size)); } +#define access_ok(addr, size) __access_ok((unsigned long)addr, size) # define __FIXUP_SECTION ".section .fixup,\"ax\"\n" # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n" -- cgit v1.2.3