From 8780356ef630aa577fd4daa49e49b79674711fae Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 3 May 2018 17:06:31 -0700 Subject: [PATCH] x86/asm/memcpy_mcsafe: Define copy_to_iter_mcsafe() Use the updated memcpy_mcsafe() implementation to define copy_user_mcsafe() and copy_to_iter_mcsafe(). The most significant difference from typical copy_to_iter() is that the ITER_KVEC and ITER_BVEC iterator types can fail to complete a full transfer. Signed-off-by: Dan Williams Cc: Al Viro Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: hch@lst.de Cc: linux-fsdevel@vger.kernel.org Cc: linux-nvdimm@lists.01.org Link: http://lkml.kernel.org/r/152539239150.31796.9189779163576449784.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ingo Molnar --- arch/x86/Kconfig | 1 + arch/x86/include/asm/uaccess_64.h | 11 +++++++ include/linux/uio.h | 15 ++++++++++ lib/iov_iter.c | 61 +++++++++++++++++++++++++++++++++++++++ 4 files changed, 88 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index c07f492..6ca22706 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -60,6 +60,7 @@ config X86 select ARCH_HAS_PMEM_API if X86_64 select ARCH_HAS_REFCOUNT select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64 + select ARCH_HAS_UACCESS_MCSAFE if X86_64 select ARCH_HAS_SET_MEMORY select ARCH_HAS_SG_CHAIN select ARCH_HAS_STRICT_KERNEL_RWX diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h index c63efc0..62acb61 100644 --- a/arch/x86/include/asm/uaccess_64.h +++ b/arch/x86/include/asm/uaccess_64.h @@ -47,6 +47,17 @@ copy_user_generic(void *to, const void *from, unsigned len) } static __always_inline __must_check unsigned long +copy_to_user_mcsafe(void *to, const void *from, unsigned len) +{ + unsigned long ret; + + __uaccess_begin(); + ret = memcpy_mcsafe(to, from, len); + __uaccess_end(); + return ret; +} + +static __always_inline __must_check unsigned long raw_copy_from_user(void *dst, const void __user *src, unsigned long size) { int ret = 0; diff --git a/include/linux/uio.h b/include/linux/uio.h index e67e12a..f5766e8 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -154,6 +154,12 @@ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i); #define _copy_from_iter_flushcache _copy_from_iter_nocache #endif +#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE +size_t _copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i); +#else +#define _copy_to_iter_mcsafe _copy_to_iter +#endif + static __always_inline __must_check size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) { @@ -163,6 +169,15 @@ size_t copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) return _copy_from_iter_flushcache(addr, bytes, i); } +static __always_inline __must_check +size_t copy_to_iter_mcsafe(void *addr, size_t bytes, struct iov_iter *i) +{ + if (unlikely(!check_copy_size(addr, bytes, false))) + return 0; + else + return _copy_to_iter_mcsafe(addr, bytes, i); +} + size_t iov_iter_zero(size_t bytes, struct iov_iter *); unsigned long iov_iter_alignment(const struct iov_iter *i); unsigned long iov_iter_gap_alignment(const struct iov_iter *i); diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 9702126..70ebc8e 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -573,6 +573,67 @@ size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) } EXPORT_SYMBOL(_copy_to_iter); +#ifdef CONFIG_ARCH_HAS_UACCESS_MCSAFE +static int copyout_mcsafe(void __user *to, const void *from, size_t n) +{ + if (access_ok(VERIFY_WRITE, to, n)) { + kasan_check_read(from, n); + n = copy_to_user_mcsafe((__force void *) to, from, n); + } + return n; +} + +static unsigned long memcpy_mcsafe_to_page(struct page *page, size_t offset, + const char *from, size_t len) +{ + unsigned long ret; + char *to; + + to = kmap_atomic(page); + ret = memcpy_mcsafe(to + offset, from, len); + kunmap_atomic(to); + + return ret; +} + +size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i) +{ + const char *from = addr; + unsigned long rem, curr_addr, s_addr = (unsigned long) addr; + + if (unlikely(i->type & ITER_PIPE)) { + WARN_ON(1); + return 0; + } + if (iter_is_iovec(i)) + might_fault(); + iterate_and_advance(i, bytes, v, + copyout_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), + ({ + rem = memcpy_mcsafe_to_page(v.bv_page, v.bv_offset, + (from += v.bv_len) - v.bv_len, v.bv_len); + if (rem) { + curr_addr = (unsigned long) from; + bytes = curr_addr - s_addr - rem; + return bytes; + } + }), + ({ + rem = memcpy_mcsafe(v.iov_base, (from += v.iov_len) - v.iov_len, + v.iov_len); + if (rem) { + curr_addr = (unsigned long) from; + bytes = curr_addr - s_addr - rem; + return bytes; + } + }) + ) + + return bytes; +} +EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe); +#endif /* CONFIG_ARCH_HAS_UACCESS_MCSAFE */ + size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) { char *to = addr; -- 2.7.4