diff options
author | Helge Deller <deller@gmx.de> | 2013-06-29 14:03:14 +0200 |
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committer | Helge Deller <deller@gmx.de> | 2013-11-07 22:29:14 +0100 |
commit | 63379c135331c724d40a87b98eb62d2122981341 (patch) | |
tree | 35ef859d3afae3d73c0cb92c1dbd7cb79227deb3 | |
parent | 3a7452b4449d34f2eec377e45036f5e0808aff09 (diff) | |
download | linux-63379c135331c724d40a87b98eb62d2122981341.tar.bz2 |
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 <deller@gmx.de>
-rw-r--r-- | arch/parisc/include/asm/uaccess.h | 46 |
1 files changed, 42 insertions, 4 deletions
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 <asm/processor.h> #include <asm/page.h> #include <asm/cache.h> #include <asm/errno.h> #include <asm-generic/uaccess-unaligned.h> +#include <linux/sched.h> + #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) |