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| author | Arnd Bergmann <arnd@arndb.de> | 2022-02-15 17:59:41 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-28 09:59:56 +0200 |
| commit | 547e4a8415d403c0af8810cd1a1fd5f7e152cd97 (patch) | |
| tree | df8077811cea3ba4e8a2d918c79904252a7489bd | |
| parent | e047a3860fe3fbb10130f52d792d210cb25e582a (diff) | |
| download | linux-stable-547e4a8415d403c0af8810cd1a1fd5f7e152cd97.tar.gz linux-stable-547e4a8415d403c0af8810cd1a1fd5f7e152cd97.tar.bz2 linux-stable-547e4a8415d403c0af8810cd1a1fd5f7e152cd97.zip | |
m68k: fix access_ok for coldfire
commit 26509034bef198525d5936c116cbd0c3fa491c0b upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 ba670523885c..60b786eb2254 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)); } /* |