From 118816de3383ff12769349784689141355cc787c Mon Sep 17 00:00:00 2001 From: Florian Weimer Date: Mon, 19 Dec 2022 18:56:55 +0100 Subject: libio: Convert __vswprintf_internal to buffers (bug 27857) Always null-terminate the buffer and set E2BIG if the buffer is too small. This fixes bug 27857. Reviewed-by: Adhemerval Zanella --- libio/tst_swprintf.c | 31 ++++++++++++++-- libio/vswprintf.c | 100 ++++++++++----------------------------------------- 2 files changed, 46 insertions(+), 85 deletions(-) (limited to 'libio') diff --git a/libio/tst_swprintf.c b/libio/tst_swprintf.c index 1f997b9..169951d 100644 --- a/libio/tst_swprintf.c +++ b/libio/tst_swprintf.c @@ -1,4 +1,5 @@ #include +#include #include #include #include @@ -37,6 +38,8 @@ do_test (void) for (n = 0; n < array_length (tests); ++n) { + wmemset (buf, 0xabcd, array_length (buf)); + errno = 0; ssize_t res = swprintf (buf, tests[n].n, L"%s", tests[n].str); if (tests[n].exp < 0 && res >= 0) @@ -52,9 +55,31 @@ do_test (void) swprintf (buf, %zu, L\"%%s\", \"%s\") expected to return %zd, but got %zd\n", tests[n].n, tests[n].str, tests[n].exp, res); } - else - printf ("swprintf (buf, %zu, L\"%%s\", \"%s\") OK\n", - tests[n].n, tests[n].str); + else if (res < 0 + && tests[n].n > 0 + && wcsnlen (buf, array_length (buf)) == array_length (buf)) + { + support_record_failure (); + printf ("\ +error: swprintf (buf, %zu, L\"%%s\", \"%s\") missing null terminator\n", + tests[n].n, tests[n].str); + } + else if (res < 0 + && tests[n].n > 0 + && wcsnlen (buf, array_length (buf)) < array_length (buf) + && buf[wcsnlen (buf, array_length (buf)) + 1] != 0xabcd) + { + support_record_failure (); + printf ("\ +error: swprintf (buf, %zu, L\"%%s\", \"%s\") out of bounds write\n", + tests[n].n, tests[n].str); + } + + if (res < 0 && tests[n].n < 0) + TEST_COMPARE (errno, E2BIG); + + printf ("swprintf (buf, %zu, L\"%%s\", \"%s\") OK\n", + tests[n].n, tests[n].str); } TEST_COMPARE (swprintf (buf, array_length (buf), L"%.0s", "foo"), 0); diff --git a/libio/vswprintf.c b/libio/vswprintf.c index 5a9ccdf..f53545c 100644 --- a/libio/vswprintf.c +++ b/libio/vswprintf.c @@ -24,101 +24,37 @@ This exception applies to code released by its copyright holders in files containing the exception. */ -#include "libioP.h" -#include "strfile.h" - - -static wint_t _IO_wstrn_overflow (FILE *fp, wint_t c) __THROW; - -static wint_t -_IO_wstrn_overflow (FILE *fp, wint_t c) -{ - /* When we come to here this means the user supplied buffer is - filled. But since we must return the number of characters which - would have been written in total we must provide a buffer for - further use. We can do this by writing on and on in the overflow - buffer in the _IO_wstrnfile structure. */ - _IO_wstrnfile *snf = (_IO_wstrnfile *) fp; - - if (fp->_wide_data->_IO_buf_base != snf->overflow_buf) - { - _IO_wsetb (fp, snf->overflow_buf, - snf->overflow_buf + (sizeof (snf->overflow_buf) - / sizeof (wchar_t)), 0); - - fp->_wide_data->_IO_write_base = snf->overflow_buf; - fp->_wide_data->_IO_read_base = snf->overflow_buf; - fp->_wide_data->_IO_read_ptr = snf->overflow_buf; - fp->_wide_data->_IO_read_end = (snf->overflow_buf - + (sizeof (snf->overflow_buf) - / sizeof (wchar_t))); - } - - fp->_wide_data->_IO_write_ptr = snf->overflow_buf; - fp->_wide_data->_IO_write_end = snf->overflow_buf; - - /* Since we are not really interested in storing the characters - which do not fit in the buffer we simply ignore it. */ - return c; -} - - -const struct _IO_jump_t _IO_wstrn_jumps libio_vtable attribute_hidden = -{ - JUMP_INIT_DUMMY, - JUMP_INIT(finish, _IO_wstr_finish), - JUMP_INIT(overflow, (_IO_overflow_t) _IO_wstrn_overflow), - JUMP_INIT(underflow, (_IO_underflow_t) _IO_wstr_underflow), - JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow), - JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wstr_pbackfail), - JUMP_INIT(xsputn, _IO_wdefault_xsputn), - JUMP_INIT(xsgetn, _IO_wdefault_xsgetn), - JUMP_INIT(seekoff, _IO_wstr_seekoff), - JUMP_INIT(seekpos, _IO_default_seekpos), - JUMP_INIT(setbuf, _IO_default_setbuf), - JUMP_INIT(sync, _IO_default_sync), - JUMP_INIT(doallocate, _IO_wdefault_doallocate), - JUMP_INIT(read, _IO_default_read), - JUMP_INIT(write, _IO_default_write), - JUMP_INIT(seek, _IO_default_seek), - JUMP_INIT(close, _IO_default_close), - JUMP_INIT(stat, _IO_default_stat), - JUMP_INIT(showmanyc, _IO_default_showmanyc), - JUMP_INIT(imbue, _IO_default_imbue) -}; - +#include +#include +#include +#include int __vswprintf_internal (wchar_t *string, size_t maxlen, const wchar_t *format, va_list args, unsigned int mode_flags) { - _IO_wstrnfile sf; - int ret; - struct _IO_wide_data wd; -#ifdef _IO_MTSAFE_IO - sf.f._sbf._f._lock = NULL; -#endif - if (maxlen == 0) /* Since we have to write at least the terminating L'\0' a buffer length of zero always makes the function fail. */ return -1; - _IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstrn_jumps); - _IO_fwide (&sf.f._sbf._f, 1); - string[0] = L'\0'; - _IO_wstr_init_static (&sf.f._sbf._f, string, maxlen - 1, string); - ret = __vfwprintf_internal ((FILE *) &sf.f._sbf, format, args, mode_flags); + struct __wprintf_buffer buf; + __wprintf_buffer_init (&buf, string, maxlen, __wprintf_buffer_mode_swprintf); - if (sf.f._sbf._f._wide_data->_IO_buf_base == sf.overflow_buf) - /* ISO C99 requires swprintf/vswprintf to return an error if the - output does not fit in the provided buffer. */ - return -1; + __wprintf_buffer (&buf, format, args, mode_flags); + + if (buf.write_ptr == buf.write_end) + { + /* Buffer has been filled exactly, excluding the null wide + character. This is an error because the null wide character + is required. */ + buf.write_end[-1] = L'\0'; + return -1; + } - /* Terminate the string. */ - *sf.f._sbf._f._wide_data->_IO_write_ptr = '\0'; + buf.write_ptr[0] = L'\0'; - return ret; + return __wprintf_buffer_done (&buf); } int -- cgit v1.1