diff options
| -rw-r--r-- | arch/openrisc/include/asm/Kbuild | 1 | ||||
| -rw-r--r-- | arch/sparc/Kconfig | 1 | ||||
| -rw-r--r-- | arch/sparc/include/asm/Kbuild | 1 | ||||
| -rw-r--r-- | arch/sparc/include/asm/uaccess_32.h | 22 | ||||
| -rw-r--r-- | arch/sparc/include/asm/uaccess_64.h | 8 | ||||
| -rw-r--r-- | arch/sparc/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/sparc/lib/ksyms.c | 2 | ||||
| -rw-r--r-- | arch/sparc/lib/strlen_user_32.S | 109 | ||||
| -rw-r--r-- | arch/sparc/lib/strlen_user_64.S | 97 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess_32.h | 17 | ||||
| -rw-r--r-- | arch/x86/include/asm/uaccess_64.h | 3 | ||||
| -rw-r--r-- | arch/x86/include/asm/word-at-a-time.h | 32 | ||||
| -rw-r--r-- | arch/x86/lib/usercopy.c | 97 | ||||
| -rw-r--r-- | arch/x86/lib/usercopy_32.c | 41 | ||||
| -rw-r--r-- | arch/x86/lib/usercopy_64.c | 48 | ||||
| -rw-r--r-- | fs/namei.c | 22 | ||||
| -rw-r--r-- | include/asm-generic/word-at-a-time.h | 52 | ||||
| -rw-r--r-- | lib/Kconfig | 3 | ||||
| -rw-r--r-- | lib/Makefile | 1 | ||||
| -rw-r--r-- | lib/strncpy_from_user.c | 47 | ||||
| -rw-r--r-- | lib/strnlen_user.c | 138 |
23 files changed, 259 insertions, 490 deletions
diff --git a/arch/openrisc/include/asm/Kbuild b/arch/openrisc/include/asm/Kbuild index c936483..3f35c38 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 15e9e05..83bd051 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 2c2e388..67f83e0 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 59586b5..53a28dd 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 dcdfb89..7c831d8 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 943d98d..dff4096 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 6b278ab..3b31218 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 8c8a371..0000000 --- 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 c3df71f..0000000 --- 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 81c3e8b..d700811 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 851fe0d..04cd688 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 8084bc73..576e39b 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 fcd4b6f..8e796fb 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 ae03fac..5b238981 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 2e4e4b0..f61ee67 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 883b216..1781b2f 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 0d0326f..e5b130b 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)) { @@ -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 0000000..3f21f1b --- /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 3e63af0..a9e1540 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 2a1d7f9..8c31a0c 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 c4c09b0..bb2b201 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 0000000..90900ec --- /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); |
