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authorArnd Bergmann <arnd@arndb.de>2022-02-15 17:59:41 +0100
committerArnd Bergmann <arnd@arndb.de>2022-02-25 09:36:05 +0100
commit26509034bef198525d5936c116cbd0c3fa491c0b (patch)
treeb79eb6f6559b81f8c2fa5fd5cf5318798063ef7c
parent15f3d81a8c8a564cbc8642cf95c548d02db035a7 (diff)
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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>
-rw-r--r--arch/m68k/include/asm/uaccess.h15
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));
}
/*