Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v2] ARM: uaccess: Implement strict user copy checks | Date | Sat, 28 Aug 2010 11:56:56 +0200 |
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On Saturday 28 August 2010 09:43:04 Heiko Carstens wrote: > In function 'copy_from_user', > inlined from '__tun_chr_ioctl' at drivers/net/tun.c:1200: > /linux-2.6/arch/s390/include/asm/uaccess.h:297: warning: call to 'copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct
I wrote this one, and I can't think of an easy way to do fix it without increasing the code complexity or size.
> In function 'copy_from_user', > inlined from 'write_file_bool' at fs/debugfs/file.c:434: > /linux-2.6/arch/s390/include/asm/uaccess.h:297: warning: call to 'copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct > In function 'copy_from_user', > inlined from 'packet_getsockopt' at net/packet/af_packet.c:2123: > /linux-2.6/arch/s390/include/asm/uaccess.h:297: warning: call to 'copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct
These look like the compiler is not smart enough. Both make sure that we copy at most the size of the object, or less if the user didn't pass all of it.
> In function 'copy_from_user', > inlined from 'compat_sys_socketcall' at net/compat.c:783: > /linux-2.6/arch/s390/include/asm/uaccess.h:297: warning: call to 'copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct
I don't think the compiler has a chance to figure this one out. However, I don't see the warning on x86. Maybe x86-gcc has a bug.
Arnd
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