Messages in this thread Patch in this message | | | Date | Thu, 28 Mar 2019 08:24:21 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86/asm: add __user on copy_user_handle_tail() pointers |
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On Thu, Feb 28, 2019 at 06:50:27PM +0000, Ben Dooks wrote: > The copy_user_handle_tail() clearly uses both from and to as pointers > to user-space memory. This triggers sparse warning on using the calls > to get and put to user-space. This can be fixed easily by changing the > call to take __user annotated pointer.s
Well, but copy_user_generic() (which ends up calling the copy_user_handle_tail() eventually) casts those __user pointers to (__force void *). Converting them back to __user looks strange to me.
Linus?
Leaving in the rest for reference.
> arch/x86/lib/usercopy_64.c:68:21: warning: incorrect type in argument 1 (different address spaces) > arch/x86/lib/usercopy_64.c:68:21: expected void const volatile [noderef] <asn:1>*<noident> > arch/x86/lib/usercopy_64.c:68:21: got char * > arch/x86/lib/usercopy_64.c:70:21: warning: incorrect type in argument 1 (different address spaces) > arch/x86/lib/usercopy_64.c:70:21: expected void const volatile [noderef] <asn:1>*<noident> > arch/x86/lib/usercopy_64.c:70:21: got char *to > > Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> > --- > arch/x86/include/asm/uaccess_64.h | 2 +- > arch/x86/lib/usercopy_64.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h > index a9d637bc301d..cbca2cb28939 100644 > --- a/arch/x86/include/asm/uaccess_64.h > +++ b/arch/x86/include/asm/uaccess_64.h > @@ -208,7 +208,7 @@ __copy_from_user_flushcache(void *dst, const void __user *src, unsigned size) > } > > unsigned long > -copy_user_handle_tail(char *to, char *from, unsigned len); > +copy_user_handle_tail(char __user *to, char __user *from, unsigned len); > > unsigned long > mcsafe_handle_tail(char *to, char *from, unsigned len); > diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c > index ee42bb0cbeb3..aa180424e77a 100644 > --- a/arch/x86/lib/usercopy_64.c > +++ b/arch/x86/lib/usercopy_64.c > @@ -60,7 +60,7 @@ EXPORT_SYMBOL(clear_user); > * it is not necessary to optimize tail handling. > */ > __visible unsigned long > -copy_user_handle_tail(char *to, char *from, unsigned len) > +copy_user_handle_tail(char __user *to, char __user *from, unsigned len) > { > for (; len; --len, to++) { > char c; > -- > 2.20.1 >
-- Regards/Gruss, Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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