From 35dc62de3d5d73a91d4ca8fa9799b510a34d170d Mon Sep 17 00:00:00 2001 From: Aaron Merey Date: Thu, 19 Sep 2024 09:53:23 -0400 Subject: [PATCH] Add another test for fclose on an unopened file Add new file libio/tst-fclose-unopened2.c that tests whether fclose on an unopened file returns EOF. This test differs from tst-fclose-unopened.c by ensuring the file's buffer is allocated prior to double-fclose. A comment in tst-fclose-unopened.c now clarifies that it is testing a file with an unallocated buffer. Calling fclose on unopened files normally causes a use-after-free bug, however the standard streams are an exception since they are not deallocated by fclose. Tested for x86_64. Reviewed-by: Carlos O'Donell --- libio/Makefile | 12 ++++++++ libio/tst-fclose-unopened.c | 8 +++-- libio/tst-fclose-unopened2.c | 51 ++++++++++++++++++++++++++++++++ libio/tst-fclose-unopened2.input | 1 + 4 files changed, 69 insertions(+), 3 deletions(-) create mode 100644 libio/tst-fclose-unopened2.c create mode 100644 libio/tst-fclose-unopened2.input diff --git a/libio/Makefile b/libio/Makefile index 59f3ee0b7c..ae90e343ad 100644 --- a/libio/Makefile +++ b/libio/Makefile @@ -96,6 +96,7 @@ tests = \ tst-ext \ tst-ext2 \ tst-fclose-unopened \ + tst-fclose-unopened2 \ tst-fdopen-seek-failure \ tst-fgetc-after-eof \ tst-fgetwc \ @@ -251,6 +252,9 @@ LDFLAGS-tst-bz24228 = -Wl,--version-script=tst-bz24228.map tst_wprintf2-ARGS = "Some Text" +tst-fclose-unopened2-ENV = \ + MALLOC_TRACE=$(objpfx)tst-fclose-unopened2.mtrace \ + LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so test-fmemopen-ENV = MALLOC_TRACE=$(objpfx)test-fmemopen.mtrace \ LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so tst-fdopen-seek-failure-ENV = \ @@ -275,6 +279,8 @@ generated += \ tst-bz22415.mtrace \ tst-bz24228.check \ tst-bz24228.mtrace \ + tst-fclose-unopened2.check \ + tst-fclose-unopened2.mtrace \ tst-fdopen-seek-failure.check \ tst-fdopen-seek-failure.mtrace \ tst-fopenloc.check \ @@ -313,6 +319,7 @@ tests-special += \ $(objpfx)test-fmemopen-mem.out \ $(objpfx)tst-bz22415-mem.out \ $(objpfx)tst-bz24228-mem.out \ + $(objpfx)tst-fclose-unopened2-mem.out \ $(objpfx)tst-fdopen-seek-failure-mem.out \ $(objpfx)tst-fopenloc-mem.out \ # tests-special @@ -400,6 +407,11 @@ $(objpfx)test-fmemopen-mem.out: $(objpfx)test-fmemopen.out $(common-objpfx)malloc/mtrace $(objpfx)test-fmemopen.mtrace > $@; \ $(evaluate-test) +$(objpfx)tst-fclose-unopened2-mem.out: $(objpfx)tst-fclose-unopened2.out + $(common-objpfx)malloc/mtrace \ + $(objpfx)tst-fclose-unopened2.mtrace > $@; \ + $(evaluate-test) + $(objpfx)tst-fdopen-seek-failure-mem.out: $(objpfx)tst-fdopen-seek-failure.out $(common-objpfx)malloc/mtrace \ $(objpfx)tst-fdopen-seek-failure.mtrace > $@; \ diff --git a/libio/tst-fclose-unopened.c b/libio/tst-fclose-unopened.c index 1f1cad042d..4fed2ffdfe 100644 --- a/libio/tst-fclose-unopened.c +++ b/libio/tst-fclose-unopened.c @@ -19,9 +19,11 @@ #include #include -/* Verify that fclose on an unopened file returns EOF. This is not part - of the fclose external contract but there are dependancies on this - behaviour. */ +/* Verify that fclose on an unopened file returns EOF. This test uses + a file with an unallocated buffer. + + This is not part of the fclose external contract but there are + dependencies on this behaviour. */ static int do_test (void) diff --git a/libio/tst-fclose-unopened2.c b/libio/tst-fclose-unopened2.c new file mode 100644 index 0000000000..1e99d9dc3d --- /dev/null +++ b/libio/tst-fclose-unopened2.c @@ -0,0 +1,51 @@ +/* Test using fclose on an unopened file. + Copyright (C) 2024 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 + . */ + +#include +#include +#include + +/* Verify that fclose on an unopened file returns EOF. This test uses + a file with an allocated buffer. + + This is not part of the fclose external contract but there are + dependencies on this behaviour. */ + +static int +do_test (void) +{ + mtrace (); + + /* Input file tst-fclose-unopened2.input has 6 bytes plus newline. */ + char buf[6]; + + /* Read from the file to ensure its internal buffer is allocated. */ + TEST_COMPARE (fread (buf, 1, sizeof (buf), stdin), sizeof (buf)); + + TEST_COMPARE (fclose (stdin), 0); + + /* Attempt to close the unopened file and verify that EOF is returned. + Calling fclose on a file twice normally causes a use-after-free bug, + however the standard streams are an exception since they are not + deallocated by fclose. */ + TEST_COMPARE (fclose (stdin), EOF); + + return 0; +} + +#include diff --git a/libio/tst-fclose-unopened2.input b/libio/tst-fclose-unopened2.input new file mode 100644 index 0000000000..399f9ba41a --- /dev/null +++ b/libio/tst-fclose-unopened2.input @@ -0,0 +1 @@ +fclose -- 2.43.5