From: Christoph Hellwig <hch@lst.de> To: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@lst.de>, Linus Torvalds <torvalds@linux-foundation.org>, Al Viro <viro@zeniv.linux.org.uk>, Michael Ellerman <mpe@ellerman.id.au>, x86@kernel.org, linux-arch@vger.kernel.org, Kees Cook <keescook@chromium.org>, linux-kernel@vger.kernel.org, Luis Chamberlain <mcgrof@kernel.org>, linux-fsdevel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Alexey Dobriyan <adobriyan@gmail.com> Subject: Re: [PATCH 14/14] powerpc: remove address space overrides using set_fs() Date: Thu, 3 Sep 2020 17:56:44 +0200 [thread overview] Message-ID: <20200903155644.GA23521@lst.de> (raw) In-Reply-To: <20200903154909.GA23023@lst.de> On Thu, Sep 03, 2020 at 05:49:09PM +0200, Christoph Hellwig wrote: > On Thu, Sep 03, 2020 at 05:43:25PM +0200, Christophe Leroy wrote: > > > > > > Le 03/09/2020 à 16:22, Christoph Hellwig a écrit : > >> Stop providing the possibility to override the address space using > >> set_fs() now that there is no need for that any more. > >> > >> Signed-off-by: Christoph Hellwig <hch@lst.de> > >> --- > > > > > >> -static inline int __access_ok(unsigned long addr, unsigned long size, > >> - mm_segment_t seg) > >> +static inline bool __access_ok(unsigned long addr, unsigned long size) > >> { > >> - if (addr > seg.seg) > >> - return 0; > >> - return (size == 0 || size - 1 <= seg.seg - addr); > >> + if (addr >= TASK_SIZE_MAX) > >> + return false; > >> + return size == 0 || size <= TASK_SIZE_MAX - addr; > >> } > > > > You don't need to test size == 0 anymore. It used to be necessary because > > of the 'size - 1', as size is unsigned. > > > > Now you can directly do > > > > return size <= TASK_SIZE_MAX - addr; > > > > If size is 0, this will always be true (because you already know that addr > > is not >= TASK_SIZE_MAX > > True. What do you think of Linus' comment about always using the > ppc32 version on ppc64 as well with this? i.e. something like this folded in: diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 5363f7fc6dd06c..be070254e50943 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -11,26 +11,14 @@ #ifdef __powerpc64__ /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */ #define TASK_SIZE_MAX TASK_SIZE_USER64 - -/* - * This check is sufficient because there is a large enough gap between user - * addresses and the kernel addresses. - */ -static inline bool __access_ok(unsigned long addr, unsigned long size) -{ - return addr < TASK_SIZE_MAX && size < TASK_SIZE_MAX; -} - #else #define TASK_SIZE_MAX TASK_SIZE +#endif static inline bool __access_ok(unsigned long addr, unsigned long size) { - if (addr >= TASK_SIZE_MAX) - return false; - return size == 0 || size <= TASK_SIZE_MAX - addr; + return addr < TASK_SIZE_MAX && size <= TASK_SIZE_MAX - addr; } -#endif /* __powerpc64__ */ #define access_ok(addr, size) \ (__chk_user_ptr(addr), \
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de> To: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Kees Cook <keescook@chromium.org>, x86@kernel.org, linux-kernel@vger.kernel.org, Alexey Dobriyan <adobriyan@gmail.com>, Luis Chamberlain <mcgrof@kernel.org>, Al Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org, Linus Torvalds <torvalds@linux-foundation.org>, Christoph Hellwig <hch@lst.de> Subject: Re: [PATCH 14/14] powerpc: remove address space overrides using set_fs() Date: Thu, 3 Sep 2020 17:56:44 +0200 [thread overview] Message-ID: <20200903155644.GA23521@lst.de> (raw) In-Reply-To: <20200903154909.GA23023@lst.de> On Thu, Sep 03, 2020 at 05:49:09PM +0200, Christoph Hellwig wrote: > On Thu, Sep 03, 2020 at 05:43:25PM +0200, Christophe Leroy wrote: > > > > > > Le 03/09/2020 à 16:22, Christoph Hellwig a écrit : > >> Stop providing the possibility to override the address space using > >> set_fs() now that there is no need for that any more. > >> > >> Signed-off-by: Christoph Hellwig <hch@lst.de> > >> --- > > > > > >> -static inline int __access_ok(unsigned long addr, unsigned long size, > >> - mm_segment_t seg) > >> +static inline bool __access_ok(unsigned long addr, unsigned long size) > >> { > >> - if (addr > seg.seg) > >> - return 0; > >> - return (size == 0 || size - 1 <= seg.seg - addr); > >> + if (addr >= TASK_SIZE_MAX) > >> + return false; > >> + return size == 0 || size <= TASK_SIZE_MAX - addr; > >> } > > > > You don't need to test size == 0 anymore. It used to be necessary because > > of the 'size - 1', as size is unsigned. > > > > Now you can directly do > > > > return size <= TASK_SIZE_MAX - addr; > > > > If size is 0, this will always be true (because you already know that addr > > is not >= TASK_SIZE_MAX > > True. What do you think of Linus' comment about always using the > ppc32 version on ppc64 as well with this? i.e. something like this folded in: diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h index 5363f7fc6dd06c..be070254e50943 100644 --- a/arch/powerpc/include/asm/uaccess.h +++ b/arch/powerpc/include/asm/uaccess.h @@ -11,26 +11,14 @@ #ifdef __powerpc64__ /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */ #define TASK_SIZE_MAX TASK_SIZE_USER64 - -/* - * This check is sufficient because there is a large enough gap between user - * addresses and the kernel addresses. - */ -static inline bool __access_ok(unsigned long addr, unsigned long size) -{ - return addr < TASK_SIZE_MAX && size < TASK_SIZE_MAX; -} - #else #define TASK_SIZE_MAX TASK_SIZE +#endif static inline bool __access_ok(unsigned long addr, unsigned long size) { - if (addr >= TASK_SIZE_MAX) - return false; - return size == 0 || size <= TASK_SIZE_MAX - addr; + return addr < TASK_SIZE_MAX && size <= TASK_SIZE_MAX - addr; } -#endif /* __powerpc64__ */ #define access_ok(addr, size) \ (__chk_user_ptr(addr), \
next prev parent reply other threads:[~2020-09-03 15:57 UTC|newest] Thread overview: 115+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-03 14:22 remove the last set_fs() in common code, and remove it for x86 and powerpc v3 Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 01/14] proc: remove a level of indentation in proc_get_inode Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 02/14] proc: cleanup the compat vs no compat file ops Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 03/14] proc: add a read_iter method to proc proc_ops Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 04/14] sysctl: Convert to iter interfaces Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 05/14] fs: don't allow kernel reads and writes without iter ops Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-10-01 22:38 ` Eric Biggers 2020-10-01 22:38 ` Eric Biggers 2020-10-01 22:40 ` Al Viro 2020-10-01 22:40 ` Al Viro 2020-10-02 16:27 ` Linus Torvalds 2020-10-02 16:27 ` Linus Torvalds 2020-10-09 22:06 ` Eric Biggers 2020-10-09 22:06 ` Eric Biggers 2020-10-10 1:03 ` Linus Torvalds 2020-10-10 1:03 ` Linus Torvalds 2020-10-10 1:19 ` Eric Biggers 2020-10-10 1:19 ` Eric Biggers 2020-10-10 1:29 ` Linus Torvalds 2020-10-10 1:29 ` Linus Torvalds 2020-10-10 1:55 ` Alexander Viro 2020-10-10 1:55 ` Alexander Viro 2020-10-14 5:51 ` Christoph Hellwig 2020-10-14 5:51 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 06/14] fs: don't allow splice read/write without explicit ops Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 07/14] uaccess: add infrastructure for kernel builds with set_fs() Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 08/14] test_bitmap: remove user bitmap tests Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 09/14] lkdtm: remove set_fs-based tests Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 10/14] x86: move PAGE_OFFSET, TASK_SIZE & friends to page_{32,64}_types.h Christoph Hellwig 2020-09-03 14:22 ` [PATCH 10/14] x86: move PAGE_OFFSET, TASK_SIZE & friends to page_{32, 64}_types.h Christoph Hellwig 2020-09-03 14:22 ` [PATCH 11/14] x86: make TASK_SIZE_MAX usable from assembly code Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 12/14] x86: remove address space overrides using set_fs() Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 21:30 ` David Laight 2020-09-03 21:30 ` David Laight 2020-09-03 23:25 ` Linus Torvalds 2020-09-03 23:25 ` Linus Torvalds 2020-09-04 7:59 ` David Laight 2020-09-04 7:59 ` David Laight 2020-09-04 2:55 ` Al Viro 2020-09-04 2:55 ` Al Viro 2020-09-04 4:41 ` Al Viro 2020-09-04 4:41 ` Al Viro 2020-09-04 6:38 ` Christoph Hellwig 2020-09-04 6:38 ` Christoph Hellwig 2020-09-04 7:47 ` Christoph Hellwig 2020-09-04 7:47 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 13/14] powerpc: use non-set_fs based maccess routines Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 14:22 ` [PATCH 14/14] powerpc: remove address space overrides using set_fs() Christoph Hellwig 2020-09-03 14:22 ` Christoph Hellwig 2020-09-03 15:43 ` Christophe Leroy 2020-09-03 15:49 ` Christoph Hellwig 2020-09-03 15:49 ` Christoph Hellwig 2020-09-03 15:56 ` Christoph Hellwig [this message] 2020-09-03 15:56 ` Christoph Hellwig 2020-09-03 16:03 ` Christophe Leroy 2020-09-03 16:03 ` Christophe Leroy 2020-09-03 14:28 ` remove the last set_fs() in common code, and remove it for x86 and powerpc v3 Al Viro 2020-09-03 14:28 ` Al Viro 2020-09-03 14:30 ` Christoph Hellwig 2020-09-03 14:30 ` Christoph Hellwig 2020-09-03 14:36 ` Al Viro 2020-09-03 14:36 ` Al Viro 2020-09-03 14:40 ` Christoph Hellwig 2020-09-03 14:40 ` Christoph Hellwig 2020-09-09 17:31 ` Linus Torvalds 2020-09-09 17:31 ` Linus Torvalds 2020-09-09 18:40 ` Segher Boessenkool 2020-09-09 18:40 ` Segher Boessenkool 2020-09-09 21:33 ` Linus Torvalds 2020-09-09 21:33 ` Linus Torvalds 2020-09-10 8:04 ` David Laight 2020-09-10 8:04 ` David Laight 2020-09-10 8:13 ` Christophe Leroy 2020-09-10 8:13 ` Christophe Leroy 2020-09-10 9:26 ` David Laight 2020-09-10 9:26 ` David Laight 2020-09-10 12:26 ` David Laight 2020-09-10 12:26 ` David Laight 2020-09-10 15:20 ` Segher Boessenkool 2020-09-10 15:20 ` Segher Boessenkool 2020-09-10 15:31 ` David Laight 2020-09-10 15:31 ` David Laight 2020-09-10 17:15 ` Segher Boessenkool 2020-09-10 17:15 ` Segher Boessenkool 2020-09-10 15:16 ` Segher Boessenkool 2020-09-10 15:16 ` Segher Boessenkool 2020-09-10 15:44 ` Segher Boessenkool 2020-09-10 15:44 ` Segher Boessenkool 2020-09-03 15:49 ` Linus Torvalds 2020-09-03 15:49 ` Linus Torvalds 2020-09-04 6:00 ` Ingo Molnar 2020-09-04 6:00 ` Ingo Molnar 2020-09-04 17:58 ` Alexey Dobriyan 2020-09-04 17:58 ` Alexey Dobriyan 2020-09-04 18:42 ` Linus Torvalds 2020-09-04 18:42 ` Linus Torvalds 2020-09-04 21:01 ` David Laight 2020-09-04 21:01 ` David Laight 2020-09-05 7:16 ` Christophe Leroy 2020-09-05 7:16 ` Christophe Leroy 2020-09-05 10:13 ` David Laight 2020-09-05 10:13 ` David Laight
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