Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
On Wed, Nov 13, 2013 at 12:57:13PM -0800, H. Peter Anvin wrote: > On 11/13/2013 10:39 AM, Kees Cook wrote: > > Hi Guenter, > > > > On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: > >> __builtin_object_size is known to be broken on gcc 4.6+. > >> See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. > >> > >> This causes unnecssary build warnings and errors such as > >> > >> In function 'copy_from_user', inlined from 'sb16_copy_from_user' > >>at sound/oss/sb_audio.c:878:22: > >> arch/x86/include/asm/uaccess_32.h:211:26: error: call to > >> 'copy_from_user_overflow' > >>declared with attribute error: copy_from_user() buffer size is not > >> provably correct > >> make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) > >> > >> Disable it where broken. > > > > Is there an alternative? This means that things like > > DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think > > this is _always_ broken, just under certain situations, right? > > > > It would be one thing to block it for, say, gcc 4.6 and 4.7 only, but > without an upper cap I don't think this is at all okay. > Also please have a look into https://lkml.org/lkml/2013/10/21/52. That patch has been accepted (3df7b41aa5e); maybe above commit (2fb0815c9) is now unnecessary and can be reverted. I don't know about parisc (Jan was concerned about that), but at least on x86 I don't see above warning anymore after reverting my patch. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
On 11/13/2013 10:39 AM, Kees Cook wrote: > Hi Guenter, > > On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: >> __builtin_object_size is known to be broken on gcc 4.6+. >> See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. >> >> This causes unnecssary build warnings and errors such as >> >> In function 'copy_from_user', inlined from 'sb16_copy_from_user' >> at sound/oss/sb_audio.c:878:22: >> arch/x86/include/asm/uaccess_32.h:211:26: error: call to >> 'copy_from_user_overflow' >> declared with attribute error: copy_from_user() buffer size is not >> provably correct >> make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) >> >> Disable it where broken. > > Is there an alternative? This means that things like > DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think > this is _always_ broken, just under certain situations, right? > It would be one thing to block it for, say, gcc 4.6 and 4.7 only, but without an upper cap I don't think this is at all okay. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
On Wed, Nov 13, 2013 at 10:39:13AM -0800, Kees Cook wrote: > Hi Guenter, > > On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: > > __builtin_object_size is known to be broken on gcc 4.6+. > > See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. > > > > This causes unnecssary build warnings and errors such as > > > > In function 'copy_from_user', inlined from 'sb16_copy_from_user' > > at sound/oss/sb_audio.c:878:22: > > arch/x86/include/asm/uaccess_32.h:211:26: error: call to > > 'copy_from_user_overflow' > > declared with attribute error: copy_from_user() buffer size is not > > provably correct > > make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) > > > > Disable it where broken. > > Is there an alternative? This means that things like > DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think > this is _always_ broken, just under certain situations, right? > There was a recent proposal to address the problem differently and then revert this patch. Not sure what happened with it. I can try digging it up if necessary. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
Hi Guenter, On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: > __builtin_object_size is known to be broken on gcc 4.6+. > See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. > > This causes unnecssary build warnings and errors such as > > In function 'copy_from_user', inlined from 'sb16_copy_from_user' > at sound/oss/sb_audio.c:878:22: > arch/x86/include/asm/uaccess_32.h:211:26: error: call to > 'copy_from_user_overflow' > declared with attribute error: copy_from_user() buffer size is not > provably correct > make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) > > Disable it where broken. Is there an alternative? This means that things like DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think this is _always_ broken, just under certain situations, right? -Kees > > Signed-off-by: Guenter Roeck > --- > include/linux/compiler-gcc4.h |2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h > index 68b162d..842de22 100644 > --- a/include/linux/compiler-gcc4.h > +++ b/include/linux/compiler-gcc4.h > @@ -13,7 +13,7 @@ > #define __must_check __attribute__((warn_unused_result)) > #define __compiler_offsetof(a,b) __builtin_offsetof(a,b) > > -#if GCC_VERSION >= 40100 > +#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 > # define __compiletime_object_size(obj) __builtin_object_size(obj, 0) > #endif > > -- > 1.7.9.7 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
Hi Guenter, On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: __builtin_object_size is known to be broken on gcc 4.6+. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. This causes unnecssary build warnings and errors such as In function 'copy_from_user', inlined from 'sb16_copy_from_user' at sound/oss/sb_audio.c:878:22: arch/x86/include/asm/uaccess_32.h:211:26: error: call to 'copy_from_user_overflow' declared with attribute error: copy_from_user() buffer size is not provably correct make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) Disable it where broken. Is there an alternative? This means that things like DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think this is _always_ broken, just under certain situations, right? -Kees Signed-off-by: Guenter Roeck li...@roeck-us.net --- include/linux/compiler-gcc4.h |2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 68b162d..842de22 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -13,7 +13,7 @@ #define __must_check __attribute__((warn_unused_result)) #define __compiler_offsetof(a,b) __builtin_offsetof(a,b) -#if GCC_VERSION = 40100 +#if GCC_VERSION = 40100 GCC_VERSION 40600 # define __compiletime_object_size(obj) __builtin_object_size(obj, 0) #endif -- 1.7.9.7 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
On Wed, Nov 13, 2013 at 10:39:13AM -0800, Kees Cook wrote: Hi Guenter, On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: __builtin_object_size is known to be broken on gcc 4.6+. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. This causes unnecssary build warnings and errors such as In function 'copy_from_user', inlined from 'sb16_copy_from_user' at sound/oss/sb_audio.c:878:22: arch/x86/include/asm/uaccess_32.h:211:26: error: call to 'copy_from_user_overflow' declared with attribute error: copy_from_user() buffer size is not provably correct make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) Disable it where broken. Is there an alternative? This means that things like DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think this is _always_ broken, just under certain situations, right? There was a recent proposal to address the problem differently and then revert this patch. Not sure what happened with it. I can try digging it up if necessary. Guenter -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
On 11/13/2013 10:39 AM, Kees Cook wrote: Hi Guenter, On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: __builtin_object_size is known to be broken on gcc 4.6+. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. This causes unnecssary build warnings and errors such as In function 'copy_from_user', inlined from 'sb16_copy_from_user' at sound/oss/sb_audio.c:878:22: arch/x86/include/asm/uaccess_32.h:211:26: error: call to 'copy_from_user_overflow' declared with attribute error: copy_from_user() buffer size is not provably correct make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) Disable it where broken. Is there an alternative? This means that things like DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think this is _always_ broken, just under certain situations, right? It would be one thing to block it for, say, gcc 4.6 and 4.7 only, but without an upper cap I don't think this is at all okay. -hpa -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
On Wed, Nov 13, 2013 at 12:57:13PM -0800, H. Peter Anvin wrote: On 11/13/2013 10:39 AM, Kees Cook wrote: Hi Guenter, On Fri, Apr 12, 2013 at 07:49:08PM -0700, Guenter Roeck wrote: __builtin_object_size is known to be broken on gcc 4.6+. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. This causes unnecssary build warnings and errors such as In function 'copy_from_user', inlined from 'sb16_copy_from_user' at sound/oss/sb_audio.c:878:22: arch/x86/include/asm/uaccess_32.h:211:26: error: call to 'copy_from_user_overflow' declared with attribute error: copy_from_user() buffer size is not provably correct make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) Disable it where broken. Is there an alternative? This means that things like DEBUG_STRICT_USER_COPY_CHECKS are being rendered useless. I don't think this is _always_ broken, just under certain situations, right? It would be one thing to block it for, say, gcc 4.6 and 4.7 only, but without an upper cap I don't think this is at all okay. Also please have a look into https://lkml.org/lkml/2013/10/21/52. That patch has been accepted (3df7b41aa5e); maybe above commit (2fb0815c9) is now unnecessary and can be reverted. I don't know about parisc (Jan was concerned about that), but at least on x86 I don't see above warning anymore after reverting my patch. Guenter -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
__builtin_object_size is known to be broken on gcc 4.6+. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. This causes unnecssary build warnings and errors such as In function 'copy_from_user', inlined from 'sb16_copy_from_user' at sound/oss/sb_audio.c:878:22: arch/x86/include/asm/uaccess_32.h:211:26: error: call to 'copy_from_user_overflow' declared with attribute error: copy_from_user() buffer size is not provably correct make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) Disable it where broken. Signed-off-by: Guenter Roeck --- include/linux/compiler-gcc4.h |2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 68b162d..842de22 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -13,7 +13,7 @@ #define __must_check __attribute__((warn_unused_result)) #define __compiler_offsetof(a,b) __builtin_offsetof(a,b) -#if GCC_VERSION >= 40100 +#if GCC_VERSION >= 40100 && GCC_VERSION < 40600 # define __compiletime_object_size(obj) __builtin_object_size(obj, 0) #endif -- 1.7.9.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] gcc4: Disable __compiletime_object_size for GCC 4.6+
__builtin_object_size is known to be broken on gcc 4.6+. See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48880 for details. This causes unnecssary build warnings and errors such as In function 'copy_from_user', inlined from 'sb16_copy_from_user' at sound/oss/sb_audio.c:878:22: arch/x86/include/asm/uaccess_32.h:211:26: error: call to 'copy_from_user_overflow' declared with attribute error: copy_from_user() buffer size is not provably correct make[3]: [sound/oss/sb_audio.o] Error 1 (ignored) Disable it where broken. Signed-off-by: Guenter Roeck li...@roeck-us.net --- include/linux/compiler-gcc4.h |2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 68b162d..842de22 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -13,7 +13,7 @@ #define __must_check __attribute__((warn_unused_result)) #define __compiler_offsetof(a,b) __builtin_offsetof(a,b) -#if GCC_VERSION = 40100 +#if GCC_VERSION = 40100 GCC_VERSION 40600 # define __compiletime_object_size(obj) __builtin_object_size(obj, 0) #endif -- 1.7.9.7 -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
