| Message ID | 0288334225edc99d98d70c896494e19c3bd9361a.1542648335.git.andreyknvl@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kasan: add software tag-based mode for arm64 | expand |
On Mon, Nov 19, 2018 at 06:26:25PM +0100, Andrey Konovalov wrote: > Move the untagged_addr() macro from arch/arm64/include/asm/uaccess.h > to arch/arm64/include/asm/memory.h to be later reused by KASAN. > > Also make the untagged_addr() macro accept all kinds of address types > (void *, unsigned long, etc.). This allows not to specify type casts in > each place where the macro is used. This is done by using __typeof__. > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> > --- > arch/arm64/include/asm/memory.h | 8 ++++++++ > arch/arm64/include/asm/uaccess.h | 7 ------- > 2 files changed, 8 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 05fbc7ffcd31..deb95be44392 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -73,6 +73,14 @@ > #define KERNEL_START _text > #define KERNEL_END _end > > +/* > + * When dealing with data aborts, watchpoints, or instruction traps we may end > + * up with a tagged userland pointer. Clear the tag to get a sane pointer to > + * pass on to access_ok(), for instance. > + */ > +#define untagged_addr(addr) \ > + (__typeof__(addr))sign_extend64((__u64)(addr), 55) Minor nits: * s/__u64/u64/ (or s/__u64/unsigned long/), since this isn't a UAPI header. * Please move this down into the #ifndef __ASSEMBLY__ block, after we include <linux/bitops.h>, which is necessary for sign_extend64(). With those fixed up, this patch looks sound to me: Acked-by: Mark Rutland <mark.rutland@arm.com> Thanks, Mark. > + > /* > * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual > * address space for the shadow region respectively. They can bloat the stack > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index 07c34087bd5e..281a1e47263d 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -96,13 +96,6 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si > return ret; > } > > -/* > - * When dealing with data aborts, watchpoints, or instruction traps we may end > - * up with a tagged userland pointer. Clear the tag to get a sane pointer to > - * pass on to access_ok(), for instance. > - */ > -#define untagged_addr(addr) sign_extend64(addr, 55) > - > #define access_ok(type, addr, size) __range_ok(addr, size) > #define user_addr_max get_fs > > -- > 2.19.1.1215.g8438c0b245-goog >
On Fri, Nov 23, 2018 at 6:37 PM, Mark Rutland <mark.rutland@arm.com> wrote: > On Mon, Nov 19, 2018 at 06:26:25PM +0100, Andrey Konovalov wrote: >> Move the untagged_addr() macro from arch/arm64/include/asm/uaccess.h >> to arch/arm64/include/asm/memory.h to be later reused by KASAN. >> >> Also make the untagged_addr() macro accept all kinds of address types >> (void *, unsigned long, etc.). This allows not to specify type casts in >> each place where the macro is used. This is done by using __typeof__. >> >> Signed-off-by: Andrey Konovalov <andreyknvl@google.com> >> --- >> arch/arm64/include/asm/memory.h | 8 ++++++++ >> arch/arm64/include/asm/uaccess.h | 7 ------- >> 2 files changed, 8 insertions(+), 7 deletions(-) >> >> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h >> index 05fbc7ffcd31..deb95be44392 100644 >> --- a/arch/arm64/include/asm/memory.h >> +++ b/arch/arm64/include/asm/memory.h >> @@ -73,6 +73,14 @@ >> #define KERNEL_START _text >> #define KERNEL_END _end >> >> +/* >> + * When dealing with data aborts, watchpoints, or instruction traps we may end >> + * up with a tagged userland pointer. Clear the tag to get a sane pointer to >> + * pass on to access_ok(), for instance. >> + */ >> +#define untagged_addr(addr) \ >> + (__typeof__(addr))sign_extend64((__u64)(addr), 55) > > Minor nits: > > * s/__u64/u64/ (or s/__u64/unsigned long/), since this isn't a UAPI > header. > > * Please move this down into the #ifndef __ASSEMBLY__ block, after we > include <linux/bitops.h>, which is necessary for sign_extend64(). > > With those fixed up, this patch looks sound to me: > > Acked-by: Mark Rutland <mark.rutland@arm.com> > > Thanks, > Mark. Will do in v12, thanks! > >> + >> /* >> * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual >> * address space for the shadow region respectively. They can bloat the stack >> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h >> index 07c34087bd5e..281a1e47263d 100644 >> --- a/arch/arm64/include/asm/uaccess.h >> +++ b/arch/arm64/include/asm/uaccess.h >> @@ -96,13 +96,6 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si >> return ret; >> } >> >> -/* >> - * When dealing with data aborts, watchpoints, or instruction traps we may end >> - * up with a tagged userland pointer. Clear the tag to get a sane pointer to >> - * pass on to access_ok(), for instance. >> - */ >> -#define untagged_addr(addr) sign_extend64(addr, 55) >> - >> #define access_ok(type, addr, size) __range_ok(addr, size) >> #define user_addr_max get_fs >> >> -- >> 2.19.1.1215.g8438c0b245-goog >> > > -- > You received this message because you are subscribed to the Google Groups "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com. > To post to this group, send email to kasan-dev@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/20181123173739.osgvnnhmptdgtlnl%40lakrids.cambridge.arm.com. > For more options, visit https://groups.google.com/d/optout.
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 05fbc7ffcd31..deb95be44392 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -73,6 +73,14 @@ #define KERNEL_START _text #define KERNEL_END _end +/* + * When dealing with data aborts, watchpoints, or instruction traps we may end + * up with a tagged userland pointer. Clear the tag to get a sane pointer to + * pass on to access_ok(), for instance. + */ +#define untagged_addr(addr) \ + (__typeof__(addr))sign_extend64((__u64)(addr), 55) + /* * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual * address space for the shadow region respectively. They can bloat the stack diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 07c34087bd5e..281a1e47263d 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -96,13 +96,6 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si return ret; } -/* - * When dealing with data aborts, watchpoints, or instruction traps we may end - * up with a tagged userland pointer. Clear the tag to get a sane pointer to - * pass on to access_ok(), for instance. - */ -#define untagged_addr(addr) sign_extend64(addr, 55) - #define access_ok(type, addr, size) __range_ok(addr, size) #define user_addr_max get_fs
Move the untagged_addr() macro from arch/arm64/include/asm/uaccess.h to arch/arm64/include/asm/memory.h to be later reused by KASAN. Also make the untagged_addr() macro accept all kinds of address types (void *, unsigned long, etc.). This allows not to specify type casts in each place where the macro is used. This is done by using __typeof__. Signed-off-by: Andrey Konovalov <andreyknvl@google.com> --- arch/arm64/include/asm/memory.h | 8 ++++++++ arch/arm64/include/asm/uaccess.h | 7 ------- 2 files changed, 8 insertions(+), 7 deletions(-)