From: Nathan Chancellor <nathan@kernel.org>
To: Kees Cook <keescook@chromium.org>, kernel test robot <lkp@intel.com>
Cc: clang-built-linux@googlegroups.com, kbuild-all@lists.01.org,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [linux-next:master 8858/10077] fs/statfs.c:131:3: warning: 'memcpy' will always overflow; destination buffer has size 64, but size argument is 84
Date: Tue, 24 Aug 2021 19:41:50 -0700 [thread overview]
Message-ID: <2751fd54-f28e-6318-2fc1-3fa5d4a98b2d@kernel.org> (raw)
In-Reply-To: <202108241916.7EFB8D5E1C@keescook>
On 8/24/2021 7:17 PM, Kees Cook wrote:
> On Wed, Aug 25, 2021 at 05:59:01AM +0800, kernel test robot wrote:
>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head: 372b2891c15acbf7b90d948b08ac174bde77102c
>> commit: 185e297653a7e0431db813764d2efb9ffd09160c [8858/10077] fortify: Explicitly disable Clang support
>> config: i386-randconfig-a016-20210824 (attached as .config)
>> compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project d26000e4cc2bc65e207a84fa26cb6e374d60aa12)
>> reproduce (this is a W=1 build):
>> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=185e297653a7e0431db813764d2efb9ffd09160c
>> git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>> git fetch --no-tags linux-next master
>> git checkout 185e297653a7e0431db813764d2efb9ffd09160c
>> # save the attached .config to linux build tree
>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=i386
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>>
>> All warnings (new ones prefixed by >>):
>>
>> clang-14: warning: optimization flag '-falign-jumps=0' is not supported [-Wignored-optimization-argument]
>> In file included from fs/statfs.c:2:
>> In file included from include/linux/syscalls.h:76:
>> In file included from include/uapi/linux/aio_abi.h:31:
>> In file included from include/linux/fs.h:6:
>> In file included from include/linux/wait_bit.h:8:
>> In file included from include/linux/wait.h:9:
>> In file included from include/linux/spinlock.h:51:
>> In file included from include/linux/preempt.h:78:
>> In file included from arch/x86/include/asm/preempt.h:7:
>> In file included from include/linux/thread_info.h:60:
>> arch/x86/include/asm/thread_info.h:172:13: warning: calling '__builtin_frame_address' with a nonzero argument is unsafe [-Wframe-address]
>> oldframe = __builtin_frame_address(1);
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~
>> arch/x86/include/asm/thread_info.h:174:11: warning: calling '__builtin_frame_address' with a nonzero argument is unsafe [-Wframe-address]
>> frame = __builtin_frame_address(2);
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~
>> In file included from fs/statfs.c:2:
>> In file included from include/linux/syscalls.h:87:
>> In file included from include/trace/syscall.h:7:
>> In file included from include/linux/trace_events.h:10:
>> In file included from include/linux/perf_event.h:49:
>> In file included from include/linux/ftrace.h:22:
>> arch/x86/include/asm/ftrace.h:7:3: error: Compiler does not support fentry?
>> # error Compiler does not support fentry?
>> ^
I think that this error is why there is a fortify warning below (no idea
how) but applying my patch [1] which came out of [2] fixes this error
and I do not see any warning in this file with that config.
[1]: https://lore.kernel.org/r/20210824022640.2170859-1-nathan@kernel.org
[2]: https://lore.kernel.org/r/YSQE2f5teuvKLkON@Ryzen-9-3900X.localdomain/
Cheers,
Nathan
>> In file included from fs/statfs.c:2:
>> In file included from include/linux/syscalls.h:87:
>> In file included from include/trace/syscall.h:7:
>> In file included from include/linux/trace_events.h:10:
>> In file included from include/linux/perf_event.h:49:
>> include/linux/ftrace.h:843:9: warning: calling '__builtin_return_address' with a nonzero argument is unsafe [-Wframe-address]
>> addr = CALLER_ADDR1;
>> ^~~~~~~~~~~~
>> include/linux/ftrace.h:830:38: note: expanded from macro 'CALLER_ADDR1'
>> #define CALLER_ADDR1 ((unsigned long)ftrace_return_address(1))
>> ^~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/ftrace.h:823:36: note: expanded from macro 'ftrace_return_address'
>> # define ftrace_return_address(n) __builtin_return_address(n)
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/ftrace.h:846:9: warning: calling '__builtin_return_address' with a nonzero argument is unsafe [-Wframe-address]
>> return CALLER_ADDR2;
>> ^~~~~~~~~~~~
>> include/linux/ftrace.h:831:38: note: expanded from macro 'CALLER_ADDR2'
>> #define CALLER_ADDR2 ((unsigned long)ftrace_return_address(2))
>> ^~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/ftrace.h:823:36: note: expanded from macro 'ftrace_return_address'
>> # define ftrace_return_address(n) __builtin_return_address(n)
>> ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>> fs/statfs.c:131:3: warning: 'memcpy' will always overflow; destination buffer has size 64, but size argument is 84 [-Wfortify-source]
>> memcpy(&buf, st, sizeof(*st));
>> ^
>> arch/x86/include/asm/string_32.h:182:25: note: expanded from macro 'memcpy'
>> #define memcpy(t, f, n) __builtin_memcpy(t, f, n)
>> ^
>> 5 warnings and 1 error generated.
>>
>>
>> vim +/memcpy +131 fs/statfs.c
>>
>> c8b91accfa1059 Al Viro 2011-03-12 125
>> c8b91accfa1059 Al Viro 2011-03-12 126 static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
>> c8b91accfa1059 Al Viro 2011-03-12 127 {
>> c8b91accfa1059 Al Viro 2011-03-12 128 struct statfs buf;
>> 7ed1ee6118ae77 Al Viro 2010-03-23 129
>> c8b91accfa1059 Al Viro 2011-03-12 130 if (sizeof(buf) == sizeof(*st))
>> c8b91accfa1059 Al Viro 2011-03-12 @131 memcpy(&buf, st, sizeof(*st));
>
> Wat. Statement above this makes that assertion impossible.
>
prev parent reply other threads:[~2021-08-25 2:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 21:59 kernel test robot
2021-08-25 2:17 ` Kees Cook
2021-08-25 2:41 ` Nathan Chancellor [this message]
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