commit 21cc130b78a4db9113fb6695e2b951e697662440 Author: Dmitry V. Levin Date: Wed Feb 13 01:20:51 2019 +0000 libio: do not attempt to free wide buffers of legacy streams [BZ #24228] Commit a601b74d31ca086de38441d316a3dee24c866305 aka glibc-2.23~693 ("In preparation for fixing BZ#16734, fix failure in misc/tst-error1-mem when _G_HAVE_MMAP is turned off.") introduced a regression: _IO_unbuffer_all now invokes _IO_wsetb to free wide buffers of all files, including legacy standard files which are small statically allocated objects that do not have wide buffers and the _mode member, causing memory corruption. Another memory corruption in _IO_unbuffer_all happens when -1 is assigned to the _mode member of legacy standard files that do not have it. [BZ #24228] * libio/genops.c (_IO_unbuffer_all) [SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)]: Do not attempt to free wide buffers and access _IO_FILE_complete members of legacy libio streams. * libio/tst-bz24228.c: New file. * libio/tst-bz24228.map: Likewise. * libio/Makefile [build-shared] (tests): Add tst-bz24228. [build-shared] (generated): Add tst-bz24228.mtrace and tst-bz24228.check. [run-built-tests && build-shared] (tests-special): Add $(objpfx)tst-bz24228-mem.out. (LDFLAGS-tst-bz24228, tst-bz24228-ENV): New variables. ($(objpfx)tst-bz24228-mem.out): New rule. # Conflicts: # libio/Makefile diff --git a/libio/Makefile b/libio/Makefile index cbfaf3832a45fc22..314e03d5ce72be2d 100644 --- a/libio/Makefile +++ b/libio/Makefile @@ -73,6 +73,9 @@ ifeq (yes,$(build-shared)) # Add test-fopenloc only if shared library is enabled since it depends on # shared localedata objects. tests += tst-fopenloc +# Add tst-bz24228 only if shared library is enabled since it can never meet its +# objective with static linking because the relevant code just is not there. +tests += tst-bz24228 endif test-srcs = test-freopen @@ -153,11 +156,14 @@ CFLAGS-oldtmpfile.c += -fexceptions CFLAGS-tst_putwc.c += -DOBJPFX=\"$(objpfx)\" +LDFLAGS-tst-bz24228 = -Wl,--version-script=tst-bz24228.map + tst_wprintf2-ARGS = "Some Text" test-fmemopen-ENV = MALLOC_TRACE=$(objpfx)test-fmemopen.mtrace tst-fopenloc-ENV = MALLOC_TRACE=$(objpfx)tst-fopenloc.mtrace tst-bz22415-ENV = MALLOC_TRACE=$(objpfx)tst-bz22415.mtrace +tst-bz24228-ENV = MALLOC_TRACE=$(objpfx)tst-bz24228.mtrace generated += test-fmemopen.mtrace test-fmemopen.check generated += tst-fopenloc.mtrace tst-fopenloc.check @@ -166,6 +172,7 @@ generated += tst-bz22415.mtrace tst-bz22415.check aux := fileops genops stdfiles stdio strops ifeq ($(build-shared),yes) +generated += tst-bz24228.mtrace tst-bz24228.check aux += oldfileops oldstdfiles endif @@ -180,7 +187,8 @@ tests-special += $(objpfx)test-freopen.out $(objpfx)test-fmemopen-mem.out \ ifeq (yes,$(build-shared)) # Run tst-fopenloc-cmp.out and tst-openloc-mem.out only if shared # library is enabled since they depend on tst-fopenloc.out. -tests-special += $(objpfx)tst-fopenloc-cmp.out $(objpfx)tst-fopenloc-mem.out +tests-special += $(objpfx)tst-fopenloc-cmp.out $(objpfx)tst-fopenloc-mem.out \ + $(objpfx)tst-bz24228-mem.out endif endif @@ -232,3 +240,7 @@ $(objpfx)tst-fopenloc-mem.out: $(objpfx)tst-fopenloc.out $(objpfx)tst-bz22415-mem.out: $(objpfx)tst-bz22415.out $(common-objpfx)malloc/mtrace $(objpfx)tst-bz22415.mtrace > $@; \ $(evaluate-test) + +$(objpfx)tst-bz24228-mem.out: $(objpfx)tst-bz24228.out + $(common-objpfx)malloc/mtrace $(objpfx)tst-bz24228.mtrace > $@; \ + $(evaluate-test) diff --git a/libio/genops.c b/libio/genops.c index 2fec221b99729718..a8241dd26640bbcb 100644 --- a/libio/genops.c +++ b/libio/genops.c @@ -789,9 +789,16 @@ _IO_unbuffer_all (void) for (fp = (FILE *) _IO_list_all; fp; fp = fp->_chain) { + int legacy = 0; + +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1) + if (__glibc_unlikely (_IO_vtable_offset (fp) != 0)) + legacy = 1; +#endif + if (! (fp->_flags & _IO_UNBUFFERED) /* Iff stream is un-orientated, it wasn't used. */ - && fp->_mode != 0) + && (legacy || fp->_mode != 0)) { #ifdef _IO_MTSAFE_IO int cnt; @@ -805,7 +812,7 @@ _IO_unbuffer_all (void) __sched_yield (); #endif - if (! dealloc_buffers && !(fp->_flags & _IO_USER_BUF)) + if (! legacy && ! dealloc_buffers && !(fp->_flags & _IO_USER_BUF)) { fp->_flags |= _IO_USER_BUF; @@ -816,7 +823,7 @@ _IO_unbuffer_all (void) _IO_SETBUF (fp, NULL, 0); - if (fp->_mode > 0) + if (! legacy && fp->_mode > 0) _IO_wsetb (fp, NULL, NULL, 0); #ifdef _IO_MTSAFE_IO @@ -827,7 +834,8 @@ _IO_unbuffer_all (void) /* Make sure that never again the wide char functions can be used. */ - fp->_mode = -1; + if (! legacy) + fp->_mode = -1; } #ifdef _IO_MTSAFE_IO diff --git a/libio/tst-bz24228.c b/libio/tst-bz24228.c new file mode 100644 index 0000000000000000..6a74500d473ceeab --- /dev/null +++ b/libio/tst-bz24228.c @@ -0,0 +1,29 @@ +/* BZ #24228 check for memory corruption in legacy libio + Copyright (C) 2019 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 + +static int +do_test (void) +{ + mtrace (); + return 0; +} + +#include diff --git a/libio/tst-bz24228.map b/libio/tst-bz24228.map new file mode 100644 index 0000000000000000..4383e0817d7f5583 --- /dev/null +++ b/libio/tst-bz24228.map @@ -0,0 +1,5 @@ +# Hide the symbol from libc.so.6 to switch to the libio/oldfileops.c +# implementation when it is available for the architecture. +{ + local: _IO_stdin_used; +};