libc/include/bits/fortify/unistd.h

/*
 * Copyright (C) 2017 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#ifndef _UNISTD_H_
#error "Never include this file directly; instead, include <unistd.h>"
#endif

char* __getcwd_chk(char*, size_t, size_t) __INTRODUCED_IN(24);

ssize_t __pread_chk(int, void*, size_t, off_t, size_t) __INTRODUCED_IN(23);
ssize_t __pread_real(int, void*, size_t, off_t) __RENAME(pread);

ssize_t __pread64_chk(int, void*, size_t, off64_t, size_t) __INTRODUCED_IN(23);
ssize_t __pread64_real(int, void*, size_t, off64_t) __RENAME(pread64) __INTRODUCED_IN(12);

ssize_t __pwrite_chk(int, const void*, size_t, off_t, size_t) __INTRODUCED_IN(24);
ssize_t __pwrite_real(int, const void*, size_t, off_t) __RENAME(pwrite);

ssize_t __pwrite64_chk(int, const void*, size_t, off64_t, size_t) __INTRODUCED_IN(24);
ssize_t __pwrite64_real(int, const void*, size_t, off64_t) __RENAME(pwrite64)
  __INTRODUCED_IN(12);

ssize_t __read_chk(int, void*, size_t, size_t) __INTRODUCED_IN(21);
ssize_t __write_chk(int, const void*, size_t, size_t) __INTRODUCED_IN(24);
ssize_t __readlink_chk(const char*, char*, size_t, size_t) __INTRODUCED_IN(23);
ssize_t __readlinkat_chk(int dirfd, const char*, char*, size_t, size_t) __INTRODUCED_IN(23);

#if defined(__BIONIC_FORTIFY)

#if defined(__USE_FILE_OFFSET64)
#define __PREAD_PREFIX(x) __pread64_ ## x
#define __PWRITE_PREFIX(x) __pwrite64_ ## x
#else
#define __PREAD_PREFIX(x) __pread_ ## x
#define __PWRITE_PREFIX(x) __pwrite_ ## x
#endif

#if defined(__clang__)
#define __error_if_overflows_ssizet(what) \
    __enable_if(what > SSIZE_MAX, #what " must be <= SSIZE_MAX") \
    __errorattr(#what " must be <= SSIZE_MAX")

#define __enable_if_no_overflow_ssizet(what) \
    __enable_if((what) <= SSIZE_MAX, "enabled if " #what " <= SSIZE_MAX")

#define __error_if_overflows_objectsize(what, objsize) \
    __enable_if((objsize) != __BIONIC_FORTIFY_UNKNOWN_SIZE && \
                    (what) > (objsize), \
                "'" #what "' bytes overflows the given object") \
    __errorattr("'" #what "' bytes overflows the given object")

__BIONIC_ERROR_FUNCTION_VISIBILITY
char* getcwd(char* buf, size_t size) __overloadable
        __error_if_overflows_objectsize(size, __bos(buf));

#if __ANDROID_API__ >= __ANDROID_API_N__
__BIONIC_FORTIFY_INLINE
char* getcwd(char* const __pass_object_size buf, size_t size) __overloadable {
    size_t bos = __bos(buf);

    /*
     * Clang responds bos==0 if buf==NULL
     * (https://llvm.org/bugs/show_bug.cgi?id=23277). Given that NULL is a valid
     * value, we need to handle that.
     */
    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE || buf == NULL) {
        return __call_bypassing_fortify(getcwd)(buf, size);
    }

    return __getcwd_chk(buf, size, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_N__ */

#if __ANDROID_API__ >= __ANDROID_API_M__
__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pread(int fd, void* buf, size_t count, off_t offset) __overloadable
        __error_if_overflows_ssizet(count);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pread(int fd, void* buf, size_t count, off_t offset) __overloadable
        __enable_if_no_overflow_ssizet(count)
        __error_if_overflows_objectsize(count, __bos0(buf));

__BIONIC_FORTIFY_INLINE
ssize_t pread(int fd, void* const __pass_object_size0 buf, size_t count,
              off_t offset) __overloadable {
    size_t bos = __bos0(buf);

    if (count == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __PREAD_PREFIX(real)(fd, buf, count, offset);
    }

    return __PREAD_PREFIX(chk)(fd, buf, count, offset, bos);
}

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pread64(int fd, void* buf, size_t count, off64_t offset) __overloadable
        __error_if_overflows_ssizet(count);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pread64(int fd, void* buf, size_t count, off64_t offset) __overloadable
        __enable_if_no_overflow_ssizet(count)
        __error_if_overflows_objectsize(count, __bos0(buf));

__BIONIC_FORTIFY_INLINE
ssize_t pread64(int fd, void* const __pass_object_size0 buf, size_t count,
                off64_t offset) __overloadable {
    size_t bos = __bos0(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __pread64_real(fd, buf, count, offset);
    }

    return __pread64_chk(fd, buf, count, offset, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_M__ */

#if __ANDROID_API__ >= __ANDROID_API_N__
__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pwrite(int fd, const void* buf, size_t count, off_t offset)
        __overloadable
        __error_if_overflows_ssizet(count);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pwrite(int fd, const void* buf, size_t count, off_t offset)
        __overloadable
        __enable_if_no_overflow_ssizet(count)
        __error_if_overflows_objectsize(count, __bos0(buf));

__BIONIC_FORTIFY_INLINE
ssize_t pwrite(int fd, const void* const __pass_object_size0 buf, size_t count,
               off_t offset) __overloadable {
    size_t bos = __bos0(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __PWRITE_PREFIX(real)(fd, buf, count, offset);
    }

    return __PWRITE_PREFIX(chk)(fd, buf, count, offset, bos);
}

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pwrite64(int fd, const void* buf, size_t count, off64_t offset)
        __overloadable
        __error_if_overflows_ssizet(count);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t pwrite64(int fd, const void* buf, size_t count, off64_t offset)
        __overloadable
        __enable_if_no_overflow_ssizet(count)
        __error_if_overflows_objectsize(count, __bos0(buf));

__BIONIC_FORTIFY_INLINE
ssize_t pwrite64(int fd, const void* const __pass_object_size0 buf,
                 size_t count, off64_t offset) __overloadable {
    size_t bos = __bos0(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __pwrite64_real(fd, buf, count, offset);
    }

    return __pwrite64_chk(fd, buf, count, offset, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_N__ */

#if __ANDROID_API__ >= __ANDROID_API_L__
__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t read(int fd, void* buf, size_t count) __overloadable
        __error_if_overflows_ssizet(count);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t read(int fd, void* buf, size_t count) __overloadable
        __enable_if_no_overflow_ssizet(count)
        __error_if_overflows_objectsize(count, __bos0(buf));

__BIONIC_FORTIFY_INLINE
ssize_t read(int fd, void* const __pass_object_size0 buf, size_t count)
        __overloadable {
    size_t bos = __bos0(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __call_bypassing_fortify(read)(fd, buf, count);
    }

    return __read_chk(fd, buf, count, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_L__ */

#if __ANDROID_API__ >= __ANDROID_API_N__
__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t write(int fd, const void* buf, size_t count) __overloadable
        __error_if_overflows_ssizet(count);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t write(int fd, const void* buf, size_t count) __overloadable
        __enable_if_no_overflow_ssizet(count)
        __error_if_overflows_objectsize(count, __bos0(buf));

__BIONIC_FORTIFY_INLINE
ssize_t write(int fd, const void* const __pass_object_size0 buf, size_t count)
        __overloadable {
    size_t bos = __bos0(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __call_bypassing_fortify(write)(fd, buf, count);
    }

    return __write_chk(fd, buf, count, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_N__ */

#if __ANDROID_API__ >= __ANDROID_API_M__
__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t readlink(const char* path, char* buf, size_t size) __overloadable
        __error_if_overflows_ssizet(size);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t readlink(const char* path, char* buf, size_t size) __overloadable
        __enable_if_no_overflow_ssizet(size)
        __error_if_overflows_objectsize(size, __bos(buf));

__BIONIC_FORTIFY_INLINE
ssize_t readlink(const char* path, char* const __pass_object_size buf,
                 size_t size) __overloadable {
    size_t bos = __bos(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __call_bypassing_fortify(readlink)(path, buf, size);
    }

    return __readlink_chk(path, buf, size, bos);
}

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t readlinkat(int dirfd, const char* path, char* buf, size_t size)
        __overloadable
        __error_if_overflows_ssizet(size);

__BIONIC_ERROR_FUNCTION_VISIBILITY
ssize_t readlinkat(int dirfd, const char* path, char* buf, size_t size)
        __overloadable
        __enable_if_no_overflow_ssizet(size)
        __error_if_overflows_objectsize(size, __bos(buf));

__BIONIC_FORTIFY_INLINE
ssize_t readlinkat(int dirfd, const char* path,
                   char* const __pass_object_size buf, size_t size)
        __overloadable {
    size_t bos = __bos(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __call_bypassing_fortify(readlinkat)(dirfd, path, buf, size);
    }

    return __readlinkat_chk(dirfd, path, buf, size, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_M__ */

#undef __enable_if_no_overflow_ssizet
#undef __error_if_overflows_objectsize
#undef __error_if_overflows_ssizet
#else /* defined(__clang__) */

char* __getcwd_real(char*, size_t) __RENAME(getcwd);
ssize_t __read_real(int, void*, size_t) __RENAME(read);
ssize_t __write_real(int, const void*, size_t) __RENAME(write);
ssize_t __readlink_real(const char*, char*, size_t) __RENAME(readlink);
ssize_t __readlinkat_real(int dirfd, const char*, char*, size_t) __RENAME(readlinkat);

__errordecl(__getcwd_dest_size_error, "getcwd called with size bigger than destination");
__errordecl(__pread_dest_size_error, "pread called with size bigger than destination");
__errordecl(__pread_count_toobig_error, "pread called with count > SSIZE_MAX");
__errordecl(__pread64_dest_size_error, "pread64 called with size bigger than destination");
__errordecl(__pread64_count_toobig_error, "pread64 called with count > SSIZE_MAX");
__errordecl(__pwrite_dest_size_error, "pwrite called with size bigger than destination");
__errordecl(__pwrite_count_toobig_error, "pwrite called with count > SSIZE_MAX");
__errordecl(__pwrite64_dest_size_error, "pwrite64 called with size bigger than destination");
__errordecl(__pwrite64_count_toobig_error, "pwrite64 called with count > SSIZE_MAX");
__errordecl(__read_dest_size_error, "read called with size bigger than destination");
__errordecl(__read_count_toobig_error, "read called with count > SSIZE_MAX");
__errordecl(__write_dest_size_error, "write called with size bigger than destination");
__errordecl(__write_count_toobig_error, "write called with count > SSIZE_MAX");
__errordecl(__readlink_dest_size_error, "readlink called with size bigger than destination");
__errordecl(__readlink_size_toobig_error, "readlink called with size > SSIZE_MAX");
__errordecl(__readlinkat_dest_size_error, "readlinkat called with size bigger than destination");
__errordecl(__readlinkat_size_toobig_error, "readlinkat called with size > SSIZE_MAX");

#if __ANDROID_API__ >= __ANDROID_API_N__
__BIONIC_FORTIFY_INLINE
char* getcwd(char* buf, size_t size) __overloadable {
    size_t bos = __bos(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __getcwd_real(buf, size);
    }

    if (__builtin_constant_p(size) && (size > bos)) {
        __getcwd_dest_size_error();
    }

    if (__builtin_constant_p(size) && (size <= bos)) {
        return __getcwd_real(buf, size);
    }

    return __getcwd_chk(buf, size, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_N__ */

#if __ANDROID_API__ >= __ANDROID_API_M__
__BIONIC_FORTIFY_INLINE
ssize_t pread(int fd, void* buf, size_t count, off_t offset) {
    size_t bos = __bos0(buf);

    if (__builtin_constant_p(count) && (count > SSIZE_MAX)) {
        __PREAD_PREFIX(count_toobig_error)();
    }

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __PREAD_PREFIX(real)(fd, buf, count, offset);
    }

    if (__builtin_constant_p(count) && (count > bos)) {
        __PREAD_PREFIX(dest_size_error)();
    }

    if (__builtin_constant_p(count) && (count <= bos)) {
        return __PREAD_PREFIX(real)(fd, buf, count, offset);
    }

    return __PREAD_PREFIX(chk)(fd, buf, count, offset, bos);
}

__BIONIC_FORTIFY_INLINE
ssize_t pread64(int fd, void* buf, size_t count, off64_t offset) {
    size_t bos = __bos0(buf);

    if (__builtin_constant_p(count) && (count > SSIZE_MAX)) {
        __pread64_count_toobig_error();
    }

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __pread64_real(fd, buf, count, offset);
    }

    if (__builtin_constant_p(count) && (count > bos)) {
        __pread64_dest_size_error();
    }

    if (__builtin_constant_p(count) && (count <= bos)) {
        return __pread64_real(fd, buf, count, offset);
    }

    return __pread64_chk(fd, buf, count, offset, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_M__ */

#if __ANDROID_API__ >= __ANDROID_API_N__
__BIONIC_FORTIFY_INLINE
ssize_t pwrite(int fd, const void* buf, size_t count, off_t offset) {
    size_t bos = __bos0(buf);

    if (__builtin_constant_p(count) && (count > SSIZE_MAX)) {
        __PWRITE_PREFIX(count_toobig_error)();
    }

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __PWRITE_PREFIX(real)(fd, buf, count, offset);
    }

    if (__builtin_constant_p(count) && (count > bos)) {
        __PWRITE_PREFIX(dest_size_error)();
    }

    if (__builtin_constant_p(count) && (count <= bos)) {
        return __PWRITE_PREFIX(real)(fd, buf, count, offset);
    }

    return __PWRITE_PREFIX(chk)(fd, buf, count, offset, bos);
}

__BIONIC_FORTIFY_INLINE
ssize_t pwrite64(int fd, const void* buf, size_t count, off64_t offset) {
    size_t bos = __bos0(buf);

    if (__builtin_constant_p(count) && (count > SSIZE_MAX)) {
        __pwrite64_count_toobig_error();
    }

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __pwrite64_real(fd, buf, count, offset);
    }

    if (__builtin_constant_p(count) && (count > bos)) {
        __pwrite64_dest_size_error();
    }

    if (__builtin_constant_p(count) && (count <= bos)) {
        return __pwrite64_real(fd, buf, count, offset);
    }

    return __pwrite64_chk(fd, buf, count, offset, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_N__ */

#if __ANDROID_API__ >= __ANDROID_API_L__
__BIONIC_FORTIFY_INLINE
ssize_t read(int fd, void* buf, size_t count) {
    size_t bos = __bos0(buf);

    if (__builtin_constant_p(count) && (count > SSIZE_MAX)) {
        __read_count_toobig_error();
    }

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __read_real(fd, buf, count);
    }

    if (__builtin_constant_p(count) && (count > bos)) {
        __read_dest_size_error();
    }

    if (__builtin_constant_p(count) && (count <= bos)) {
        return __read_real(fd, buf, count);
    }

    return __read_chk(fd, buf, count, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_L__ */

#if __ANDROID_API__ >= __ANDROID_API_N__
__BIONIC_FORTIFY_INLINE
ssize_t write(int fd, const void* buf, size_t count) {
    size_t bos = __bos0(buf);

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __write_real(fd, buf, count);
    }

    if (__builtin_constant_p(count) && (count > bos)) {
        __write_dest_size_error();
    }

    if (__builtin_constant_p(count) && (count <= bos)) {
        return __write_real(fd, buf, count);
    }

    return __write_chk(fd, buf, count, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_N__ */

#if __ANDROID_API__ >= __ANDROID_API_M__
__BIONIC_FORTIFY_INLINE
ssize_t readlink(const char* path, char* buf, size_t size) {
    size_t bos = __bos(buf);

    if (__builtin_constant_p(size) && (size > SSIZE_MAX)) {
        __readlink_size_toobig_error();
    }

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __readlink_real(path, buf, size);
    }

    if (__builtin_constant_p(size) && (size > bos)) {
        __readlink_dest_size_error();
    }

    if (__builtin_constant_p(size) && (size <= bos)) {
        return __readlink_real(path, buf, size);
    }

    return __readlink_chk(path, buf, size, bos);
}

__BIONIC_FORTIFY_INLINE
ssize_t readlinkat(int dirfd, const char* path, char* buf, size_t size) {
    size_t bos = __bos(buf);

    if (__builtin_constant_p(size) && (size > SSIZE_MAX)) {
        __readlinkat_size_toobig_error();
    }

    if (bos == __BIONIC_FORTIFY_UNKNOWN_SIZE) {
        return __readlinkat_real(dirfd, path, buf, size);
    }

    if (__builtin_constant_p(size) && (size > bos)) {
        __readlinkat_dest_size_error();
    }

    if (__builtin_constant_p(size) && (size <= bos)) {
        return __readlinkat_real(dirfd, path, buf, size);
    }

    return __readlinkat_chk(dirfd, path, buf, size, bos);
}
#endif /* __ANDROID_API__ >= __ANDROID_API_M__ */
#endif /* defined(__clang__) */
#undef __PREAD_PREFIX
#undef __PWRITE_PREFIX
#endif /* defined(__BIONIC_FORTIFY) */