#include #include #include #include /* 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 << (BITS_PER_LONG - 8 - 8*(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; unsafe_get_user(c, (unsigned long __user *)src, efault); 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); /* We already handled 'unsigned long' bytes. Did we do it all ? */ if (unlikely(max <= sizeof(unsigned long))) break; max -= sizeof(unsigned long); unsafe_get_user(c, (unsigned long __user *)(src+res), efault); } 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. */ efault: 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 if pagefaults are * enabled. * * 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 a number larger than @count. User * has to check the return value against "> count". * On exception (or invalid count), returns 0. * * NOTE! You should basically never use this function. There is * almost never any valid case for using the length of a user space * string, since the string can be changed at any time by other * threads. Use "strncpy_from_user()" instead to get a stable copy * of the string. */ 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; long retval; user_access_begin(); retval = do_strnlen_user(str, count, max); user_access_end(); return retval; } 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 if pagefaults are * enabled. * * 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; long retval; user_access_begin(); retval = do_strnlen_user(str, ~0ul, max); user_access_end(); return retval; } return 0; } EXPORT_SYMBOL(strlen_user); -2/+2 2017-02-03tcp: add tcp_mss_clamp() helperEric Dumazet4-23/+8 2017-02-02net: add LINUX_MIB_PFMEMALLOCDROP counterEric Dumazet2-2/+4 2017-02-02net: ipv4: remove fib_lookup.h from devinet.c include listDavid Ahern1-2/+0 2017-02-02net: remove useless pfmemalloc settingEric Dumazet1-1/+0 2017-02-02unix: add ioctl to open a unix socket file with O_PATHAndrey Vagin1-0/+41 2017-02-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller12-104/+93 2017-02-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds10-103/+86 2017-02-01net/sched: act_psample: Remove unnecessary ASSERT_RTNLYotam Gigi1-1/+0 2017-02-01net/sched: act_sample: Fix error path in initYotam Gigi1-1/+4 2017-02-01tcp: fix 0 divide in __tcp_select_window()Eric Dumazet1-2/+4 2017-02-01ipv6: pointer math error in ip6_tnl_parse_tlv_enc_lim()Dan Carpenter1-1/+1 2017-02-01net: ipv6: add NLM_F_APPEND in notifications when applicableDavid Ahern1-0/+3 2017-02-01net: reduce skb_warn_bad_offload() noiseEric Dumazet1-3/+9 2017-02-01net/sched: matchall: Fix configuration raceYotam Gigi1-82/+45 2017-02-01rtnetlink: Handle IFLA_MASTER parameter when processing rtnl_newlinkTheuns Verwoerd1-1/+6