summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--arch/openrisc/include/asm/Kbuild1
-rw-r--r--arch/sparc/Kconfig1
-rw-r--r--arch/sparc/include/asm/Kbuild1
-rw-r--r--arch/sparc/include/asm/uaccess_32.h22
-rw-r--r--arch/sparc/include/asm/uaccess_64.h8
-rw-r--r--arch/sparc/lib/Makefile1
-rw-r--r--arch/sparc/lib/ksyms.c2
-rw-r--r--arch/sparc/lib/strlen_user_32.S109
-rw-r--r--arch/sparc/lib/strlen_user_64.S97
-rw-r--r--arch/x86/Kconfig2
-rw-r--r--arch/x86/include/asm/uaccess.h4
-rw-r--r--arch/x86/include/asm/uaccess_32.h17
-rw-r--r--arch/x86/include/asm/uaccess_64.h3
-rw-r--r--arch/x86/include/asm/word-at-a-time.h32
-rw-r--r--arch/x86/lib/usercopy.c97
-rw-r--r--arch/x86/lib/usercopy_32.c41
-rw-r--r--arch/x86/lib/usercopy_64.c48
-rw-r--r--fs/namei.c22
-rw-r--r--include/asm-generic/word-at-a-time.h52
-rw-r--r--lib/Kconfig3
-rw-r--r--lib/Makefile1
-rw-r--r--lib/strncpy_from_user.c47
-rw-r--r--lib/strnlen_user.c138
23 files changed, 259 insertions, 490 deletions
diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild
index c936483bc8e2..3f35c38d7b64 100644
--- a/arch/openrisc/include/asm/Kbuild
+++ b/arch/openrisc/include/asm/Kbuild
@@ -66,3 +66,4 @@ generic-y += topology.h
generic-y += types.h
generic-y += ucontext.h
generic-y += user.h
+generic-y += word-at-a-time.h
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 15e9e05740da..83bd051754e1 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -35,6 +35,7 @@ config SPARC
select GENERIC_CMOS_UPDATE
select GENERIC_CLOCKEVENTS
select GENERIC_STRNCPY_FROM_USER
+ select GENERIC_STRNLEN_USER
config SPARC32
def_bool !64BIT
diff --git a/arch/sparc/include/asm/Kbuild b/arch/sparc/include/asm/Kbuild
index 2c2e38821f60..67f83e0a0d68 100644
--- a/arch/sparc/include/asm/Kbuild
+++ b/arch/sparc/include/asm/Kbuild
@@ -21,3 +21,4 @@ generic-y += div64.h
generic-y += local64.h
generic-y += irq_regs.h
generic-y += local.h
+generic-y += word-at-a-time.h
diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h
index 59586b57ef1a..53a28dd59f59 100644
--- a/arch/sparc/include/asm/uaccess_32.h
+++ b/arch/sparc/include/asm/uaccess_32.h
@@ -16,6 +16,8 @@
#ifndef __ASSEMBLY__
+#include <asm/processor.h>
+
#define ARCH_HAS_SORT_EXTABLE
#define ARCH_HAS_SEARCH_EXTABLE
@@ -304,24 +306,8 @@ static inline unsigned long clear_user(void __user *addr, unsigned long n)
return n;
}
-extern long __strlen_user(const char __user *);
-extern long __strnlen_user(const char __user *, long len);
-
-static inline long strlen_user(const char __user *str)
-{
- if (!access_ok(VERIFY_READ, str, 0))
- return 0;
- else
- return __strlen_user(str);
-}
-
-static inline long strnlen_user(const char __user *str, long len)
-{
- if (!access_ok(VERIFY_READ, str, 0))
- return 0;
- else
- return __strnlen_user(str, len);
-}
+extern __must_check long strlen_user(const char __user *str);
+extern __must_check long strnlen_user(const char __user *str, long n);
#endif /* __ASSEMBLY__ */
diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
index dcdfb89cbf3f..7c831d848b4e 100644
--- a/arch/sparc/include/asm/uaccess_64.h
+++ b/arch/sparc/include/asm/uaccess_64.h
@@ -17,6 +17,8 @@
#ifndef __ASSEMBLY__
+#include <asm/processor.h>
+
/*
* Sparc64 is segmented, though more like the M68K than the I386.
* We use the secondary ASI to address user memory, which references a
@@ -257,11 +259,9 @@ extern unsigned long __must_check __clear_user(void __user *, unsigned long);
#define clear_user __clear_user
-extern long __strlen_user(const char __user *);
-extern long __strnlen_user(const char __user *, long len);
+extern __must_check long strlen_user(const char __user *str);
+extern __must_check long strnlen_user(const char __user *str, long n);
-#define strlen_user __strlen_user
-#define strnlen_user __strnlen_user
#define __copy_to_user_inatomic ___copy_to_user
#define __copy_from_user_inatomic ___copy_from_user
diff --git a/arch/sparc/lib/Makefile b/arch/sparc/lib/Makefile
index 943d98dc4cdb..dff4096f3dec 100644
--- a/arch/sparc/lib/Makefile
+++ b/arch/sparc/lib/Makefile
@@ -10,7 +10,6 @@ lib-y += strlen.o
lib-y += checksum_$(BITS).o
lib-$(CONFIG_SPARC32) += blockops.o
lib-y += memscan_$(BITS).o memcmp.o strncmp_$(BITS).o
-lib-y += strlen_user_$(BITS).o
lib-$(CONFIG_SPARC32) += divdi3.o udivdi3.o
lib-$(CONFIG_SPARC32) += copy_user.o locks.o
lib-$(CONFIG_SPARC64) += atomic_64.o
diff --git a/arch/sparc/lib/ksyms.c b/arch/sparc/lib/ksyms.c
index 6b278abdb63d..3b31218cafc6 100644
--- a/arch/sparc/lib/ksyms.c
+++ b/arch/sparc/lib/ksyms.c
@@ -15,8 +15,6 @@
/* string functions */
EXPORT_SYMBOL(strlen);
-EXPORT_SYMBOL(__strlen_user);
-EXPORT_SYMBOL(__strnlen_user);
EXPORT_SYMBOL(strncmp);
/* mem* functions */
diff --git a/arch/sparc/lib/strlen_user_32.S b/arch/sparc/lib/strlen_user_32.S
deleted file mode 100644
index 8c8a371df3c9..000000000000
--- a/arch/sparc/lib/strlen_user_32.S
+++ /dev/null
@@ -1,109 +0,0 @@
-/* strlen_user.S: Sparc optimized strlen_user code
- *
- * Return length of string in userspace including terminating 0
- * or 0 for error
- *
- * Copyright (C) 1991,1996 Free Software Foundation
- * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
- * Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
- */
-
-#define LO_MAGIC 0x01010101
-#define HI_MAGIC 0x80808080
-
-10:
- ldub [%o0], %o5
- cmp %o5, 0
- be 1f
- add %o0, 1, %o0
- andcc %o0, 3, %g0
- be 4f
- or %o4, %lo(HI_MAGIC), %o3
-11:
- ldub [%o0], %o5
- cmp %o5, 0
- be 2f
- add %o0, 1, %o0
- andcc %o0, 3, %g0
- be 5f
- sethi %hi(LO_MAGIC), %o4
-12:
- ldub [%o0], %o5
- cmp %o5, 0
- be 3f
- add %o0, 1, %o0
- b 13f
- or %o4, %lo(LO_MAGIC), %o2
-1:
- retl
- mov 1, %o0
-2:
- retl
- mov 2, %o0
-3:
- retl
- mov 3, %o0
-
- .align 4
- .global __strlen_user, __strnlen_user
-__strlen_user:
- sethi %hi(32768), %o1
-__strnlen_user:
- mov %o1, %g1
- mov %o0, %o1
- andcc %o0, 3, %g0
- bne 10b
- sethi %hi(HI_MAGIC), %o4
- or %o4, %lo(HI_MAGIC), %o3
-4:
- sethi %hi(LO_MAGIC), %o4
-5:
- or %o4, %lo(LO_MAGIC), %o2
-13:
- ld [%o0], %o5
-2:
- sub %o5, %o2, %o4
- andcc %o4, %o3, %g0
- bne 82f
- add %o0, 4, %o0
- sub %o0, %o1, %g2
-81: cmp %g2, %g1
- blu 13b
- mov %o0, %o4
- ba,a 1f
-
- /* Check every byte. */
-82: srl %o5, 24, %g5
- andcc %g5, 0xff, %g0
- be 1f
- add %o0, -3, %o4
- srl %o5, 16, %g5
- andcc %g5, 0xff, %g0
- be 1f
- add %o4, 1, %o4
- srl %o5, 8, %g5
- andcc %g5, 0xff, %g0
- be 1f
- add %o4, 1, %o4
- andcc %o5, 0xff, %g0
- bne 81b
- sub %o0, %o1, %g2
-
- add %o4, 1, %o4
-1:
- retl
- sub %o4, %o1, %o0
-
- .section .fixup,#alloc,#execinstr
- .align 4
-9:
- retl
- clr %o0
-
- .section __ex_table,#alloc
- .align 4
-
- .word 10b, 9b
- .word 11b, 9b
- .word 12b, 9b
- .word 13b, 9b
diff --git a/arch/sparc/lib/strlen_user_64.S b/arch/sparc/lib/strlen_user_64.S
deleted file mode 100644
index c3df71fa4928..000000000000
--- a/arch/sparc/lib/strlen_user_64.S
+++ /dev/null
@@ -1,97 +0,0 @@
-/* strlen_user.S: Sparc64 optimized strlen_user code
- *
- * Return length of string in userspace including terminating 0
- * or 0 for error
- *
- * Copyright (C) 1991,1996 Free Software Foundation
- * Copyright (C) 1996,1999 David S. Miller (davem@redhat.com)
- * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
- */
-
-#include <linux/linkage.h>
-#include <asm/asi.h>
-
-#define LO_MAGIC 0x01010101
-#define HI_MAGIC 0x80808080
-
- .align 4
-ENTRY(__strlen_user)
- sethi %hi(32768), %o1
-ENTRY(__strnlen_user)
- mov %o1, %g1
- mov %o0, %o1
- andcc %o0, 3, %g0
- be,pt %icc, 9f
- sethi %hi(HI_MAGIC), %o4
-10: lduba [%o0] %asi, %o5
- brz,pn %o5, 21f
- add %o0, 1, %o0
- andcc %o0, 3, %g0
- be,pn %icc, 4f
- or %o4, %lo(HI_MAGIC), %o3
-11: lduba [%o0] %asi, %o5
- brz,pn %o5, 22f
- add %o0, 1, %o0
- andcc %o0, 3, %g0
- be,pt %icc, 13f
- srl %o3, 7, %o2
-12: lduba [%o0] %asi, %o5
- brz,pn %o5, 23f
- add %o0, 1, %o0
- ba,pt %icc, 2f
-15: lda [%o0] %asi, %o5
-9: or %o4, %lo(HI_MAGIC), %o3
-4: srl %o3, 7, %o2
-13: lda [%o0] %asi, %o5
-2: sub %o5, %o2, %o4
- andcc %o4, %o3, %g0
- bne,pn %icc, 82f
- add %o0, 4, %o0
- sub %o0, %o1, %g2
-81: cmp %g2, %g1
- blu,pt %icc, 13b
- mov %o0, %o4
- ba,a,pt %xcc, 1f
-
- /* Check every byte. */
-82: srl %o5, 24, %g7
- andcc %g7, 0xff, %g0
- be,pn %icc, 1f
- add %o0, -3, %o4
- srl %o5, 16, %g7
- andcc %g7, 0xff, %g0
- be,pn %icc, 1f
- add %o4, 1, %o4
- srl %o5, 8, %g7
- andcc %g7, 0xff, %g0
- be,pn %icc, 1f
- add %o4, 1, %o4
- andcc %o5, 0xff, %g0
- bne,pt %icc, 81b
- sub %o0, %o1, %g2
- add %o4, 1, %o4
-1: retl
- sub %o4, %o1, %o0
-21: retl
- mov 1, %o0
-22: retl
- mov 2, %o0
-23: retl
- mov 3, %o0
-ENDPROC(__strlen_user)
-ENDPROC(__strnlen_user)
-
- .section .fixup,#alloc,#execinstr
- .align 4
-30:
- retl
- clr %o0
-
- .section __ex_table,"a"
- .align 4
-
- .word 10b, 30b
- .word 11b, 30b
- .word 12b, 30b
- .word 15b, 30b
- .word 13b, 30b
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 81c3e8be789a..d700811785ea 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -93,6 +93,8 @@ config X86
select GENERIC_CLOCKEVENTS_BROADCAST if X86_64 || (X86_32 && X86_LOCAL_APIC)
select GENERIC_TIME_VSYSCALL if X86_64
select KTIME_SCALAR if X86_32
+ select GENERIC_STRNCPY_FROM_USER
+ select GENERIC_STRNLEN_USER
config INSTRUCTION_DECODER
def_bool (KPROBES || PERF_EVENTS || UPROBES)
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 851fe0dc13bc..04cd6882308e 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -32,6 +32,7 @@
#define segment_eq(a, b) ((a).seg == (b).seg)
+#define user_addr_max() (current_thread_info()->addr_limit.seg)
#define __addr_ok(addr) \
((unsigned long __force)(addr) < \
(current_thread_info()->addr_limit.seg))
@@ -565,6 +566,9 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
extern __must_check long
strncpy_from_user(char *dst, const char __user *src, long count);
+extern __must_check long strlen_user(const char __user *str);
+extern __must_check long strnlen_user(const char __user *str, long n);
+
/*
* movsl can be slow when source and dest are not both 8-byte aligned
*/
diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h
index 8084bc73b18c..576e39bca6ad 100644
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -213,23 +213,6 @@ static inline unsigned long __must_check copy_from_user(void *to,
return n;
}
-/**
- * strlen_user: - Get the size of a string in user space.
- * @str: The string to measure.
- *
- * Context: User context only. This function may sleep.
- *
- * Get the size of a NUL-terminated string in user space.
- *
- * Returns the size of the string INCLUDING the terminating NUL.
- * On exception, returns 0.
- *
- * If there is a limit on the length of a valid string, you may wish to
- * consider using strnlen_user() instead.
- */
-#define strlen_user(str) strnlen_user(str, LONG_MAX)
-
-long strnlen_user(const char __user *str, long n);
unsigned long __must_check clear_user(void __user *mem, unsigned long len);
unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
diff --git a/arch/x86/include/asm/uaccess_64.h b/arch/x86/include/asm/uaccess_64.h
index fcd4b6f3ef02..8e796fbbf9c6 100644
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -208,9 +208,6 @@ int __copy_in_user(void __user *dst, const void __user *src, unsigned size)
}
}
-__must_check long strnlen_user(const char __user *str, long n);
-__must_check long __strnlen_user(const char __user *str, long n);
-__must_check long strlen_user(const char __user *str);
__must_check unsigned long clear_user(void __user *mem, unsigned long len);
__must_check unsigned long __clear_user(void __user *mem, unsigned long len);
diff --git a/arch/x86/include/asm/word-at-a-time.h b/arch/x86/include/asm/word-at-a-time.h
index ae03facfadd6..5b238981542a 100644
--- a/arch/x86/include/asm/word-at-a-time.h
+++ b/arch/x86/include/asm/word-at-a-time.h
@@ -10,6 +10,11 @@
* bit count instruction, that might be better than the multiply
* and shift, for example.
*/
+struct word_at_a_time {
+ const unsigned long one_bits, high_bits;
+};
+
+#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
#ifdef CONFIG_64BIT
@@ -37,10 +42,31 @@ static inline long count_masked_bytes(long mask)
#endif
-/* Return the high bit set in the first byte that is a zero */
-static inline unsigned long has_zero(unsigned long a)
+/* Return nonzero if it has a zero */
+static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
+{
+ unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
+ *bits = mask;
+ return mask;
+}
+
+static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
+{
+ return bits;
+}
+
+static inline unsigned long create_zero_mask(unsigned long bits)
+{
+ bits = (bits - 1) & ~bits;
+ return bits >> 7;
+}
+
+/* The mask we created is directly usable as a bytemask */
+#define zero_bytemask(mask) (mask)
+
+static inline unsigned long find_zero(unsigned long mask)
{
- return ((a - REPEAT_BYTE(0x01)) & ~a) & REPEAT_BYTE(0x80);
+ return count_masked_bytes(mask);
}
/*
diff --git a/arch/x86/lib/usercopy.c b/arch/x86/lib/usercopy.c
index 2e4e4b02c37a..f61ee67ec00f 100644
--- a/arch/x86/lib/usercopy.c
+++ b/arch/x86/lib/usercopy.c
@@ -43,100 +43,3 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n)
return len;
}
EXPORT_SYMBOL_GPL(copy_from_user_nmi);
-
-/*
- * Do a strncpy, return length of string without final '\0'.
- * 'count' is the user-supplied count (return 'count' if we
- * hit it), 'max' is the address space maximum (and we return
- * -EFAULT if we hit it).
- */
-static inline long do_strncpy_from_user(char *dst, const char __user *src, long count, unsigned long max)
-{
- long res = 0;
-
- /*
- * Truncate 'max' to the user-specified limit, so that
- * we only have one limit we need to check in the loop
- */
- if (max > count)
- max = count;
-
- while (max >= sizeof(unsigned long)) {
- unsigned long c, mask;
-
- /* Fall back to byte-at-a-time if we get a page fault */
- if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
- break;
- mask = has_zero(c);
- if (mask) {
- mask = (mask - 1) & ~mask;
- mask >>= 7;
- *(unsigned long *)(dst+res) = c & mask;
- return res + count_masked_bytes(mask);
- }
- *(unsigned long *)(dst+res) = c;
- res += sizeof(unsigned long);
- max -= sizeof(unsigned long);
- }
-
- while (max) {
- char c;
-
- if (unlikely(__get_user(c,src+res)))
- return -EFAULT;
- dst[res] = c;
- if (!c)
- return res;
- res++;
- max--;
- }
-
- /*
- * Uhhuh. We hit 'max'. But was that the user-specified maximum
- * too? If so, that's ok - we got as much as the user asked for.
- */
- if (res >= count)
- return res;
-
- /*
- * Nope: we hit the address space limit, and we still had more
- * characters the caller would have wanted. That's an EFAULT.
- */
- return -EFAULT;
-}
-
-/**
- * strncpy_from_user: - Copy a NUL terminated string from userspace.
- * @dst: Destination address, in kernel space. This buffer must be at
- * least @count bytes long.
- * @src: Source address, in user space.
- * @count: Maximum number of bytes to copy, including the trailing NUL.
- *
- * Copies a NUL-terminated string from userspace to kernel space.
- *
- * On success, returns the length of the string (not including the trailing
- * NUL).
- *
- * If access to userspace fails, returns -EFAULT (some data may have been
- * copied).
- *
- * If @count is smaller than the length of the string, copies @count bytes
- * and returns @count.
- */
-long
-strncpy_from_user(char *dst, const char __user *src, long count)
-{
- unsigned long max_addr, src_addr;
-
- if (unlikely(count <= 0))
- return 0;
-
- max_addr = current_thread_info()->addr_limit.seg;
- src_addr = (unsigned long)src;
- if (likely(src_addr < max_addr)) {
- unsigned long max = max_addr - src_addr;
- return do_strncpy_from_user(dst, src, count, max);
- }
- return -EFAULT;
-}
-EXPORT_SYMBOL(strncpy_from_user);
diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c
index 883b216c60b2..1781b2f950e2 100644
--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -95,47 +95,6 @@ __clear_user(void __user *to, unsigned long n)
}
EXPORT_SYMBOL(__clear_user);
-/**
- * strnlen_user: - Get the size of a string in user space.
- * @s: The string to measure.
- * @n: The maximum valid length
- *
- * Get the size of a NUL-terminated string in user space.
- *
- * Returns the size of the string INCLUDING the terminating NUL.
- * On exception, returns 0.
- * If the string is too long, returns a value greater than @n.
- */
-long strnlen_user(const char __user *s, long n)
-{
- unsigned long mask = -__addr_ok(s);
- unsigned long res, tmp;
-
- might_fault();
-
- __asm__ __volatile__(
- " testl %0, %0\n"
- " jz 3f\n"
- " andl %0,%%ecx\n"
- "0: repne; scasb\n"
- " setne %%al\n"
- " subl %%ecx,%0\n"
- " addl %0,%%eax\n"
- "1:\n"
- ".section .fixup,\"ax\"\n"
- "2: xorl %%eax,%%eax\n"
- " jmp 1b\n"
- "3: movb $1,%%al\n"
- " jmp 1b\n"
- ".previous\n"
- _ASM_EXTABLE(0b,2b)
- :"=&r" (n), "=&D" (s), "=&a" (res), "=&c" (tmp)
- :"0" (n), "1" (s), "2" (0), "3" (mask)
- :"cc");
- return res & mask;
-}
-EXPORT_SYMBOL(strnlen_user);
-
#ifdef CONFIG_X86_INTEL_USERCOPY
static unsigned long
__copy_user_intel(void __user *to, const void *from, unsigned long size)
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index 0d0326f388c0..e5b130bc2d0e 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -52,54 +52,6 @@ unsigned long clear_user(void __user *to, unsigned long n)
}
EXPORT_SYMBOL(clear_user);
-/*
- * Return the size of a string (including the ending 0)
- *
- * Return 0 on exception, a value greater than N if too long
- */
-
-long __strnlen_user(const char __user *s, long n)
-{
- long res = 0;
- char c;
-
- while (1) {
- if (res>n)
- return n+1;
- if (__get_user(c, s))
- return 0;
- if (!c)
- return res+1;
- res++;
- s++;
- }
-}
-EXPORT_SYMBOL(__strnlen_user);
-
-long strnlen_user(const char __user *s, long n)
-{
- if (!access_ok(VERIFY_READ, s, 1))
- return 0;
- return __strnlen_user(s, n);
-}
-EXPORT_SYMBOL(strnlen_user);
-
-long strlen_user(const char __user *s)
-{
- long res = 0;
- char c;
-
- for (;;) {
- if (get_user(c, s))
- return 0;
- if (!c)
- return res+1;
- res++;
- s++;
- }
-}
-EXPORT_SYMBOL(strlen_user);
-
unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
{
if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {
diff --git a/fs/namei.c b/fs/namei.c
index 93ff12b1a1de..c651f02c9fec 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1452,7 +1452,8 @@ EXPORT_SYMBOL(full_name_hash);
*/
static inline unsigned long hash_name(const char *name, unsigned int *hashp)
{
- unsigned long a, mask, hash, len;
+ unsigned long a, b, adata, bdata, mask, hash, len;
+ const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
hash = a = 0;
len = -sizeof(unsigned long);
@@ -1460,17 +1461,18 @@ static inline unsigned long hash_name(const char *name, unsigned int *hashp)
hash = (hash + a) * 9;
len += sizeof(unsigned long);
a = load_unaligned_zeropad(name+len);
- /* Do we have any NUL or '/' bytes in this word? */
- mask = has_zero(a) | has_zero(a ^ REPEAT_BYTE('/'));
- } while (!mask);
-
- /* The mask *below* the first high bit set */
- mask = (mask - 1) & ~mask;
- mask >>= 7;
- hash += a & mask;
+ b = a ^ REPEAT_BYTE('/');
+ } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants)));
+
+ adata = prep_zero_mask(a, adata, &constants);
+ bdata = prep_zero_mask(b, bdata, &constants);
+
+ mask = create_zero_mask(adata | bdata);
+
+ hash += a & zero_bytemask(mask);
*hashp = fold_hash(hash);
- return len + count_masked_bytes(mask);
+ return len + find_zero(mask);
}
#else
diff --git a/include/asm-generic/word-at-a-time.h b/include/asm-generic/word-at-a-time.h
new file mode 100644
index 000000000000..3f21f1b72e45
--- /dev/null
+++ b/include/asm-generic/word-at-a-time.h
@@ -0,0 +1,52 @@
+#ifndef _ASM_WORD_AT_A_TIME_H
+#define _ASM_WORD_AT_A_TIME_H
+
+/*
+ * This says "generic", but it's actually big-endian only.
+ * Little-endian can use more efficient versions of these
+ * interfaces, see for example
+ * arch/x86/include/asm/word-at-a-time.h
+ * for those.
+ */
+
+#include <linux/kernel.h>
+
+struct word_at_a_time {
+ const unsigned long high_bits, low_bits;
+};
+
+#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
+
+/* Bit set in the bytes that have a zero */
+static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
+{
+ unsigned long mask = (val & c->low_bits) + c->low_bits;
+ return ~(mask | rhs);
+}
+
+#define create_zero_mask(mask) (mask)
+
+static inline long find_zero(unsigned long mask)
+{
+ long byte = 0;
+#ifdef CONFIG_64BIT
+ if (mask >> 32)
+ mask >>= 32;
+ else
+ byte = 4;
+#endif
+ if (mask >> 16)
+ mask >>= 16;
+ else
+ byte += 2;
+ return (mask >> 8) ? byte : byte + 1;
+}
+
+static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
+{
+ unsigned long rhs = val | c->low_bits;
+ *data = rhs;
+ return (val + c->high_bits) & ~rhs;
+}
+
+#endif /* _ASM_WORD_AT_A_TIME_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 3e63af089082..a9e15403434e 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -19,6 +19,9 @@ config RATIONAL
config GENERIC_STRNCPY_FROM_USER
bool
+config GENERIC_STRNLEN_USER
+ bool
+
config GENERIC_FIND_FIRST_BIT
bool
diff --git a/lib/Makefile b/lib/Makefile
index 2a1d7f9d39a2..8c31a0cb75e9 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -126,6 +126,7 @@ obj-$(CONFIG_CLZ_TAB) += clz_tab.o
obj-$(CONFIG_DDR) += jedec_ddr_data.o
obj-$(CONFIG_GENERIC_STRNCPY_FROM_USER) += strncpy_from_user.o
+obj-$(CONFIG_GENERIC_STRNLEN_USER) += strnlen_user.o
obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index c4c09b0e96ba..bb2b201d6ad0 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -4,37 +4,7 @@
#include <linux/errno.h>
#include <asm/byteorder.h>
-
-static inline long find_zero(unsigned long mask)
-{
- long byte = 0;
-
-#ifdef __BIG_ENDIAN
-#ifdef CONFIG_64BIT
- if (mask >> 32)
- mask >>= 32;
- else
- byte = 4;
-#endif
- if (mask >> 16)
- mask >>= 16;
- else
- byte += 2;
- return (mask >> 8) ? byte : byte + 1;
-#else
-#ifdef CONFIG_64BIT
- if (!((unsigned int) mask)) {
- mask >>= 32;
- byte = 4;
- }
-#endif
- if (!(mask & 0xffff)) {
- mask >>= 16;
- byte += 2;
- }
- return (mask & 0xff) ? byte : byte + 1;
-#endif
-}
+#include <asm/word-at-a-time.h>
#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
#define IS_UNALIGNED(src, dst) 0
@@ -51,8 +21,7 @@ static inline long find_zero(unsigned long mask)
*/
static inline long do_strncpy_from_user(char *dst, const char __user *src, long count, unsigned long max)
{
- const unsigned long high_bits = REPEAT_BYTE(0xfe) + 1;
- const unsigned long low_bits = REPEAT_BYTE(0x7f);
+ const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
long res = 0;
/*
@@ -66,18 +35,16 @@ static inline long do_strncpy_from_user(char *dst, const char __user *src, long
goto byte_at_a_time;
while (max >= sizeof(unsigned long)) {
- unsigned long c, v, rhs;
+ unsigned long c, data;
/* Fall back to byte-at-a-time if we get a page fault */
if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
break;
- rhs = c | low_bits;
- v = (c + high_bits) & ~rhs;
*(unsigned long *)(dst+res) = c;
- if (v) {
- v = (c & low_bits) + low_bits;
- v = ~(v | rhs);
- return res + find_zero(v);
+ if (has_zero(c, &data, &constants)) {
+ data = prep_zero_mask(c, data, &constants);
+ data = create_zero_mask(data);
+ return res + find_zero(data);
}
res += sizeof(unsigned long);
max -= sizeof(unsigned long);
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
new file mode 100644
index 000000000000..90900ecfeb54
--- /dev/null
+++ b/lib/strnlen_user.c
@@ -0,0 +1,138 @@
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/uaccess.h>
+
+#include <asm/word-at-a-time.h>
+
+/* Set bits in the first 'n' bytes when loaded from memory */
+#ifdef __LITTLE_ENDIAN
+# define aligned_byte_mask(n) ((1ul << 8*(n))-1)
+#else
+# define aligned_byte_mask(n) (~0xfful << 8*(7-(n)))
+#endif
+
+/*
+ * Do a strnlen, return length of string *with* final '\0'.
+ * 'count' is the user-supplied count, while 'max' is the
+ * address space maximum.
+ *
+ * Return 0 for exceptions (which includes hitting the address
+ * space maximum), or 'count+1' if hitting the user-supplied
+ * maximum count.
+ *
+ * NOTE! We can sometimes overshoot the user-supplied maximum
+ * if it fits in a aligned 'long'. The caller needs to check
+ * the return value against "> max".
+ */
+static inline long do_strnlen_user(const char __user *src, unsigned long count, unsigned long max)
+{
+ const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
+ long align, res = 0;
+ unsigned long c;
+
+ /*
+ * Truncate 'max' to the user-specified limit, so that
+ * we only have one limit we need to check in the loop
+ */
+ if (max > count)
+ max = count;
+
+ /*
+ * Do everything aligned. But that means that we
+ * need to also expand the maximum..
+ */
+ align = (sizeof(long) - 1) & (unsigned long)src;
+ src -= align;
+ max += align;
+
+ if (unlikely(__get_user(c,(unsigned long __user *)src)))
+ return 0;
+ c |= aligned_byte_mask(align);
+
+ for (;;) {
+ unsigned long data;
+ if (has_zero(c, &data, &constants)) {
+ data = prep_zero_mask(c, data, &constants);
+ data = create_zero_mask(data);
+ return res + find_zero(data) + 1 - align;
+ }
+ res += sizeof(unsigned long);
+ if (unlikely(max < sizeof(unsigned long)))
+ break;
+ max -= sizeof(unsigned long);
+ if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))
+ return 0;
+ }
+ res -= align;
+
+ /*
+ * Uhhuh. We hit 'max'. But was that the user-specified maximum
+ * too? If so, return the marker for "too long".
+ */
+ if (res >= count)
+ return count+1;
+
+ /*
+ * Nope: we hit the address space limit, and we still had more
+ * characters the caller would have wanted. That's 0.
+ */
+ return 0;
+}
+
+/**
+ * strnlen_user: - Get the size of a user string INCLUDING final NUL.
+ * @str: The string to measure.
+ * @count: Maximum count (including NUL character)
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Get the size of a NUL-terminated string in user space.
+ *
+ * Returns the size of the string INCLUDING the terminating NUL.
+ * If the string is too long, returns 'count+1'.
+ * On exception (or invalid count), returns 0.
+ */
+long strnlen_user(const char __user *str, long count)
+{
+ unsigned long max_addr, src_addr;
+
+ if (unlikely(count <= 0))
+ return 0;
+
+ max_addr = user_addr_max();
+ src_addr = (unsigned long)str;
+ if (likely(src_addr < max_addr)) {
+ unsigned long max = max_addr - src_addr;
+ return do_strnlen_user(str, count, max);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(strnlen_user);
+
+/**
+ * strlen_user: - Get the size of a user string INCLUDING final NUL.
+ * @str: The string to measure.
+ *
+ * Context: User context only. This function may sleep.
+ *
+ * Get the size of a NUL-terminated string in user space.
+ *
+ * Returns the size of the string INCLUDING the terminating NUL.
+ * On exception, returns 0.
+ *
+ * If there is a limit on the length of a valid string, you may wish to
+ * consider using strnlen_user() instead.
+ */
+long strlen_user(const char __user *str)
+{
+ unsigned long max_addr, src_addr;
+
+ max_addr = user_addr_max();
+ src_addr = (unsigned long)str;
+ if (likely(src_addr < max_addr)) {
+ unsigned long max = max_addr - src_addr;
+ return do_strnlen_user(str, ~0ul, max);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(strlen_user);
OpenPOWER on IntegriCloud