diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2022-02-15 17:59:41 +0100 |
|---|---|---|
| committer | Arnd Bergmann <arnd@arndb.de> | 2022-02-25 09:36:05 +0100 |
| commit | 26509034bef198525d5936c116cbd0c3fa491c0b (patch) | |
| tree | b79eb6f6559b81f8c2fa5fd5cf5318798063ef7c /arch | |
| parent | MIPS: use simpler access_ok() (diff) | |
| download | linux-26509034bef198525d5936c116cbd0c3fa491c0b.tar.xz linux-26509034bef198525d5936c116cbd0c3fa491c0b.zip | |
m68k: fix access_ok for coldfire
While most m68k platforms use separate address spaces for user
and kernel space, at least coldfire does not, and the other
ones have a TASK_SIZE that is less than the entire 4GB address
range.
Using the default implementation of __access_ok() stops coldfire
user space from trivially accessing kernel memory.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/m68k/include/asm/uaccess.h | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/arch/m68k/include/asm/uaccess.h b/arch/m68k/include/asm/uaccess.h index 79617c0b2f91..9f0f1b6e14ed 100644 --- a/arch/m68k/include/asm/uaccess.h +++ b/arch/m68k/include/asm/uaccess.h @@ -12,14 +12,17 @@ #include <asm/extable.h> /* We let the MMU do all checking */ -static inline int access_ok(const void __user *addr, +static inline int access_ok(const void __user *ptr, unsigned long size) { - /* - * XXX: for !CONFIG_CPU_HAS_ADDRESS_SPACES this really needs to check - * for TASK_SIZE! - */ - return 1; + unsigned long limit = TASK_SIZE; + unsigned long addr = (unsigned long)ptr; + + if (IS_ENABLED(CONFIG_CPU_HAS_ADDRESS_SPACES) || + !IS_ENABLED(CONFIG_MMU)) + return 1; + + return (size <= limit) && (addr <= (limit - size)); } /* |