From 63379c135331c724d40a87b98eb62d2122981341 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Sat, 29 Jun 2013 14:03:14 +0200 Subject: parisc: implement full version of access_ok() Up to now PA-RISC could live with a trivial version of access_ok(). Our fault handlers can correctly handle fault cases. But testcases showed that we need a better access check else we won't always return correct errno failure codes to userspace. Problem showed up during 32bit userspace tests in which writev() used a 32bit memory area and length which would then wrap around on 64bit kernel. Signed-off-by: Helge Deller --- arch/parisc/include/asm/uaccess.h | 46 +++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-) (limited to 'arch/parisc/include/asm/uaccess.h') diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index 4006964d8e12..63f4dd0b49c2 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -4,11 +4,14 @@ /* * User space memory access functions */ +#include #include #include #include #include +#include + #define VERIFY_READ 0 #define VERIFY_WRITE 1 @@ -33,12 +36,43 @@ extern int __get_user_bad(void); extern int __put_kernel_bad(void); extern int __put_user_bad(void); -static inline long access_ok(int type, const void __user * addr, - unsigned long size) + +/* + * Test whether a block of memory is a valid user space address. + * Returns 0 if the range is valid, nonzero otherwise. + */ +static inline int __range_not_ok(unsigned long addr, unsigned long size, + unsigned long limit) { - return 1; + unsigned long __newaddr = addr + size; + return (__newaddr < addr || __newaddr > limit || size > limit); } +/** + * access_ok: - Checks if a user space pointer is valid + * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that + * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe + * to write to a block, it is always safe to read from it. + * @addr: User space pointer to start of block to check + * @size: Size of block to check + * + * Context: User context only. This function may sleep. + * + * Checks if a pointer to a block of memory in user space is valid. + * + * Returns true (nonzero) if the memory block may be valid, false (zero) + * if it is definitely invalid. + * + * Note that, depending on architecture, this function probably just + * checks that the pointer is in the user space range - after calling + * this function, memory access functions may still return -EFAULT. + */ +#define access_ok(type, addr, size) \ +( __chk_user_ptr(addr), \ + !__range_not_ok((unsigned long) (__force void *) (addr), \ + size, user_addr_max()) \ +) + #define put_user __put_user #define get_user __get_user @@ -219,7 +253,11 @@ extern long lstrnlen_user(const char __user *,long); /* * Complex access routines -- macros */ -#define user_addr_max() (~0UL) +#ifdef CONFIG_COMPAT +#define user_addr_max() (TASK_SIZE) +#else +#define user_addr_max() (DEFAULT_TASK_SIZE) +#endif #define strnlen_user lstrnlen_user #define strlen_user(str) lstrnlen_user(str, 0x7fffffffL) -- cgit v1.2.3-59-g8ed1b