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| author | José Bollo <jobol@nonadev.net> | 2022-03-08 09:58:16 +0100 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2022-03-08 14:25:32 -0300 |
| commit | edc696a73a7cb07b1aa68792a845a98d036ee7eb (patch) | |
| tree | 1702a42530d36697bfdb4f9dbe1426b306e47f88 | |
| parent | 2da6e439164c54bac4d5fd1320e32f8e16c1a6be (diff) | |
| download | glibc-edc696a73a7cb07b1aa68792a845a98d036ee7eb.tar glibc-edc696a73a7cb07b1aa68792a845a98d036ee7eb.tar.gz glibc-edc696a73a7cb07b1aa68792a845a98d036ee7eb.tar.bz2 glibc-edc696a73a7cb07b1aa68792a845a98d036ee7eb.zip | |
libio: Ensure output buffer for wchars (bug #28828)
The _IO_wfile_overflow does not check if the write pointer for wide
data is valid before access, different than _IO_file_overflow. This
leads to crash on some cases, as described by bug 28828.
The minimal sequence to produce the crash was:
#include <stdio.h>
#include <wchar.h>
int main (int ac, char **av)
{
setvbuf (stdout, NULL, _IOLBF, 0);
fgetwc (stdin);
fputwc (10, stdout); /*CRASH HERE!*/
return 0;
}
The "fgetwc(stdin);" is necessary since it triggers the bug by setting
the flag _IO_CURRENTLY_PUTTING on stdout indirectly (file wfileops.c,
function _IO_wfile_underflow, line 213).
Signed-off-by: Jose Bollo <jobol@nonadev.net>
| -rw-r--r-- | libio/Makefile | 2 | ||||
| -rw-r--r-- | libio/tst-bz28828.c | 32 | ||||
| -rw-r--r-- | libio/tst-bz28828.input | 1 | ||||
| -rw-r--r-- | libio/wfileops.c | 3 |
4 files changed, 36 insertions, 2 deletions
diff --git a/libio/Makefile b/libio/Makefile index 0e5f348bea..e97387743f 100644 --- a/libio/Makefile +++ b/libio/Makefile @@ -66,7 +66,7 @@ tests = tst_swprintf tst_wprintf tst_swscanf tst_wscanf tst_getwc tst_putwc \ tst-fwrite-error tst-ftell-partial-wide tst-ftell-active-handler \ tst-ftell-append tst-fputws tst-bz22415 tst-fgetc-after-eof \ tst-sprintf-ub tst-sprintf-chk-ub tst-bz24051 tst-bz24153 \ - tst-wfile-sync + tst-wfile-sync tst-bz28828 tests-internal = tst-vtables tst-vtables-interposed diff --git a/libio/tst-bz28828.c b/libio/tst-bz28828.c new file mode 100644 index 0000000000..638a6e2f13 --- /dev/null +++ b/libio/tst-bz28828.c @@ -0,0 +1,32 @@ +/* Unit test for BZ#28828. + Copyright (C) 2022 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <support/xstdio.h> +#include <support/check.h> +#include <wchar.h> + +static int +do_test (void) +{ + setvbuf (stdout, NULL, _IOLBF, 0); + fgetwc (stdin); + fputwc (10, stdout); /* It should not crash here. */ + return 0; +} + +#include <support/test-driver.c> diff --git a/libio/tst-bz28828.input b/libio/tst-bz28828.input new file mode 100644 index 0000000000..ce01362503 --- /dev/null +++ b/libio/tst-bz28828.input @@ -0,0 +1 @@ +hello diff --git a/libio/wfileops.c b/libio/wfileops.c index fb9d45b677..b59a98881f 100644 --- a/libio/wfileops.c +++ b/libio/wfileops.c @@ -412,7 +412,8 @@ _IO_wfile_overflow (FILE *f, wint_t wch) return WEOF; } /* If currently reading or no buffer allocated. */ - if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0) + if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0 + || f->_wide_data->_IO_write_base == NULL) { /* Allocate a buffer if needed. */ if (f->_wide_data->_IO_write_base == 0) |