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author | David S. Miller <davem@davemloft.net> | 2012-05-24 13:12:28 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2012-05-24 13:12:28 -0700 |
commit | 2922585b93294d47172a765115e0dbc1bfe1be19 (patch) | |
tree | acb4436987d24b2a3fb3cef02097eefbc4762bbf /arch | |
parent | 446969084d33a4064a39d280806da642c54ba4ac (diff) | |
download | linux-stable-2922585b93294d47172a765115e0dbc1bfe1be19.tar.gz linux-stable-2922585b93294d47172a765115e0dbc1bfe1be19.tar.bz2 linux-stable-2922585b93294d47172a765115e0dbc1bfe1be19.zip |
lib: Sparc's strncpy_from_user is generic enough, move under lib/
To use this, an architecture simply needs to:
1) Provide a user_addr_max() implementation via asm/uaccess.h
2) Add "select GENERIC_STRNCPY_FROM_USER" to their arch Kcnfig
3) Remove the existing strncpy_from_user() implementation and symbol
exports their architecture had.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/sparc/Kconfig | 1 | ||||
-rw-r--r-- | arch/sparc/lib/usercopy.c | 144 |
2 files changed, 1 insertions, 144 deletions
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 051af37f2b49..22474233205b 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -32,6 +32,7 @@ config SPARC select HAVE_NMI_WATCHDOG if SPARC64 select HAVE_BPF_JIT select GENERIC_SMP_IDLE_THREAD + select GENERIC_STRNCPY_FROM_USER config SPARC32 def_bool !64BIT diff --git a/arch/sparc/lib/usercopy.c b/arch/sparc/lib/usercopy.c index 0b12e91d6ccc..5c4284ce1c03 100644 --- a/arch/sparc/lib/usercopy.c +++ b/arch/sparc/lib/usercopy.c @@ -1,153 +1,9 @@ #include <linux/module.h> -#include <linux/uaccess.h> #include <linux/kernel.h> -#include <linux/errno.h> #include <linux/bug.h> -#include <asm/byteorder.h> - void copy_from_user_overflow(void) { WARN(1, "Buffer overflow detected!\n"); } EXPORT_SYMBOL(copy_from_user_overflow); - -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 -} - -#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS -#define IS_UNALIGNED(src, dst) 0 -#else -#define IS_UNALIGNED(src, dst) \ - (((long) dst | (long) src) & (sizeof(long) - 1)) -#endif - -/* - * 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) -{ - const unsigned long high_bits = REPEAT_BYTE(0xfe) + 1; - const unsigned long low_bits = REPEAT_BYTE(0x7f); - 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; - - if (IS_UNALIGNED(src, dst)) - goto byte_at_a_time; - - while (max >= sizeof(unsigned long)) { - unsigned long c, v, rhs; - - /* 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); - } - res += sizeof(unsigned long); - max -= sizeof(unsigned long); - } - -byte_at_a_time: - 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 = user_addr_max(); - 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); |