| Message ID | ebcf8256e02a7dffb292f3d800e264dce263cac5.1585811416.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RESEND,1/4] uaccess: Add user_read_access_begin/end and user_write_access_begin/end | expand |
On Thu, Apr 02, 2020 at 07:34:19AM +0000, Christophe Leroy wrote: > Add support for selective read or write user access with > user_read_access_begin/end and user_write_access_begin/end. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Kees Cook <keescook@chromium.org> -Kees > --- > arch/powerpc/include/asm/book3s/32/kup.h | 4 ++-- > arch/powerpc/include/asm/kup.h | 14 +++++++++++++- > arch/powerpc/include/asm/uaccess.h | 22 ++++++++++++++++++++++ > 3 files changed, 37 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h > index 3c0ba22dc360..1617e73bee30 100644 > --- a/arch/powerpc/include/asm/book3s/32/kup.h > +++ b/arch/powerpc/include/asm/book3s/32/kup.h > @@ -108,7 +108,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user > u32 addr, end; > > BUILD_BUG_ON(!__builtin_constant_p(dir)); > - BUILD_BUG_ON(dir == KUAP_CURRENT); > + BUILD_BUG_ON(dir & ~KUAP_READ_WRITE); > > if (!(dir & KUAP_WRITE)) > return; > @@ -131,7 +131,7 @@ static __always_inline void prevent_user_access(void __user *to, const void __us > > BUILD_BUG_ON(!__builtin_constant_p(dir)); > > - if (dir == KUAP_CURRENT) { > + if (dir & KUAP_CURRENT_WRITE) { > u32 kuap = current->thread.kuap; > > if (unlikely(!kuap)) > diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h > index 92bcd1a26d73..c745ee41ad66 100644 > --- a/arch/powerpc/include/asm/kup.h > +++ b/arch/powerpc/include/asm/kup.h > @@ -10,7 +10,9 @@ > * Use the current saved situation instead of the to/from/size params. > * Used on book3s/32 > */ > -#define KUAP_CURRENT 4 > +#define KUAP_CURRENT_READ 4 > +#define KUAP_CURRENT_WRITE 8 > +#define KUAP_CURRENT (KUAP_CURRENT_READ | KUAP_CURRENT_WRITE) > > #ifdef CONFIG_PPC64 > #include <asm/book3s/64/kup-radix.h> > @@ -101,6 +103,16 @@ static inline void prevent_current_access_user(void) > prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT); > } > > +static inline void prevent_current_read_from_user(void) > +{ > + prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_READ); > +} > + > +static inline void prevent_current_write_to_user(void) > +{ > + prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_WRITE); > +} > + > #endif /* !__ASSEMBLY__ */ > > #endif /* _ASM_POWERPC_KUAP_H_ */ > diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h > index 2f500debae21..4427d419eb1d 100644 > --- a/arch/powerpc/include/asm/uaccess.h > +++ b/arch/powerpc/include/asm/uaccess.h > @@ -468,6 +468,28 @@ static __must_check inline bool user_access_begin(const void __user *ptr, size_t > #define user_access_save prevent_user_access_return > #define user_access_restore restore_user_access > > +static __must_check inline bool > +user_read_access_begin(const void __user *ptr, size_t len) > +{ > + if (unlikely(!access_ok(ptr, len))) > + return false; > + allow_read_from_user(ptr, len); > + return true; > +} > +#define user_read_access_begin user_read_access_begin > +#define user_read_access_end prevent_current_read_from_user > + > +static __must_check inline bool > +user_write_access_begin(const void __user *ptr, size_t len) > +{ > + if (unlikely(!access_ok(ptr, len))) > + return false; > + allow_write_to_user((void __user *)ptr, len); > + return true; > +} > +#define user_write_access_begin user_write_access_begin > +#define user_write_access_end prevent_current_write_to_user > + > #define unsafe_op_wrap(op, err) do { if (unlikely(op)) goto err; } while (0) > #define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e) > #define unsafe_put_user(x, p, e) unsafe_op_wrap(__put_user_allowed(x, p), e) > -- > 2.25.0 >
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h index 3c0ba22dc360..1617e73bee30 100644 --- a/arch/powerpc/include/asm/book3s/32/kup.h +++ b/arch/powerpc/include/asm/book3s/32/kup.h @@ -108,7 +108,7 @@ static __always_inline void allow_user_access(void __user *to, const void __user u32 addr, end; BUILD_BUG_ON(!__builtin_constant_p(dir)); - BUILD_BUG_ON(dir == KUAP_CURRENT); + BUILD_BUG_ON(dir & ~KUAP_READ_WRITE); if (!(dir & KUAP_WRITE)) return; @@ -131,7 +131,7 @@ static __always_inline void prevent_user_access(void __user *to, const void __us BUILD_BUG_ON(!__builtin_constant_p(dir)); - if (dir == KUAP_CURRENT) { + if (dir & KUAP_CURRENT_WRITE) { u32 kuap = current->thread.kuap; if (unlikely(!kuap)) diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h index 92bcd1a26d73..c745ee41ad66 100644 --- a/arch/powerpc/include/asm/kup.h +++ b/arch/powerpc/include/asm/kup.h @@ -10,7 +10,9 @@ * Use the current saved situation instead of the to/from/size params. * Used on book3s/32 */ -#define KUAP_CURRENT 4 +#define KUAP_CURRENT_READ 4 +#define KUAP_CURRENT_WRITE 8 +#define KUAP_CURRENT (KUAP_CURRENT_READ | KUAP_CURRENT_WRITE) #ifdef CONFIG_PPC64 #include <asm/book3s/64/kup-radix.h> @@ -101,6 +103,16 @@ static inline void prevent_current_access_user(void) prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT); } +static inline void prevent_current_read_from_user(void) +{ + prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_READ); +} + +static inline void prevent_current_write_to_user(void) +{ + prevent_user_access(NULL, NULL, ~0UL, KUAP_CURRENT_WRITE); +} + #endif /* !__ASSEMBLY__ */ #endif /* _ASM_POWERPC_KUAP_H_ */ diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 2f500debae21..4427d419eb1d 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -468,6 +468,28 @@ static __must_check inline bool user_access_begin(const void __user *ptr, size_t #define user_access_save prevent_user_access_return #define user_access_restore restore_user_access +static __must_check inline bool +user_read_access_begin(const void __user *ptr, size_t len) +{ + if (unlikely(!access_ok(ptr, len))) + return false; + allow_read_from_user(ptr, len); + return true; +} +#define user_read_access_begin user_read_access_begin +#define user_read_access_end prevent_current_read_from_user + +static __must_check inline bool +user_write_access_begin(const void __user *ptr, size_t len) +{ + if (unlikely(!access_ok(ptr, len))) + return false; + allow_write_to_user((void __user *)ptr, len); + return true; +} +#define user_write_access_begin user_write_access_begin +#define user_write_access_end prevent_current_write_to_user + #define unsafe_op_wrap(op, err) do { if (unlikely(op)) goto err; } while (0) #define unsafe_get_user(x, p, e) unsafe_op_wrap(__get_user_allowed(x, p), e) #define unsafe_put_user(x, p, e) unsafe_op_wrap(__put_user_allowed(x, p), e)
Add support for selective read or write user access with user_read_access_begin/end and user_write_access_begin/end. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/include/asm/book3s/32/kup.h | 4 ++-- arch/powerpc/include/asm/kup.h | 14 +++++++++++++- arch/powerpc/include/asm/uaccess.h | 22 ++++++++++++++++++++++ 3 files changed, 37 insertions(+), 3 deletions(-)