A PT_NOTE in a binary could be arbitratily large, so using alloca
for it may cause stack overflow. If the note is larger than
__MAX_ALLOCA_CUTOFF, use dynamically allocated memory to read it in.
2018-05-05 Paul Pluzhnikov <ppluzhnikov@google.com>
[BZ #20419]
* elf/dl-load.c (open_verify): Fix stack overflow.
* elf/Makefile (tst-big-note): New test.
* elf/tst-big-note-lib.S: New.
* elf/tst-big-note.c: New.
(cherry picked from commit
0065aaaaae51cd60210ec3a7e13dddd8e01ffe2c)
+2018-05-05 Paul Pluzhnikov <ppluzhnikov@google.com>
+
+ [BZ #20419]
+ * elf/dl-load.c (open_verify): Fix stack overflow.
+ * elf/Makefile (tst-big-note): New test.
+ * elf/tst-big-note-lib.S: New.
+ * elf/tst-big-note.c: New.
+
2018-05-04 Stefan Liebler <stli@linux.vnet.ibm.com>
[BZ #23137]
[16750] ldd: Never run file directly.
[17343] Fix signed integer overflow in random_r
[17956] crypt: Use NSPR header files in addition to NSS header files
+ [20419] elf: Fix stack overflow with huge PT_NOTE segment
[20532] getaddrinfo: More robust handling of dlopen failures
[21242] assert: Suppress pedantic warning caused by statement expression
[21265] x86-64: Use fxsave/xsave/xsavec in _dl_runtime_resolve
tst-initorder tst-initorder2 tst-relsort1 tst-null-argv \
tst-tlsalign tst-tlsalign-extern tst-nodelete-opened \
tst-nodelete2 tst-audit11 tst-audit12 tst-dlsym-error tst-noload \
- tst-latepthread tst-tls-manydynamic tst-nodelete-dlclose
+ tst-latepthread tst-tls-manydynamic tst-nodelete-dlclose \
+ tst-big-note
# reldep9
tests-internal += loadtest unload unload2 circleload1 \
neededtest neededtest2 neededtest3 neededtest4 \
tst-audit11mod1 tst-audit11mod2 tst-auditmod11 \
tst-audit12mod1 tst-audit12mod2 tst-audit12mod3 tst-auditmod12 \
tst-latepthreadmod $(tst-tls-many-dynamic-modules) \
- tst-nodelete-dlclose-dso tst-nodelete-dlclose-plugin
+ tst-nodelete-dlclose-dso tst-nodelete-dlclose-plugin \
+ tst-big-note-lib
+
ifeq (yes,$(have-mtls-dialect-gnu2))
tests += tst-gnu2-tls1
modules-names += tst-gnu2-tls1mod
LD_HWCAP_MASK=0x1
tst-env-setuid-tunables-ENV = \
GLIBC_TUNABLES=glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096
+
+$(objpfx)tst-big-note: $(objpfx)tst-big-note-lib.so
ElfW(Ehdr) *ehdr;
ElfW(Phdr) *phdr, *ph;
ElfW(Word) *abi_note;
+ ElfW(Word) *abi_note_malloced = NULL;
unsigned int osversion;
size_t maplength;
abi_note = (void *) (fbp->buf + ph->p_offset);
else
{
- abi_note = alloca (size);
+ /* Note: __libc_use_alloca is not usable here, because
+ thread info may not have been set up yet. */
+ if (size < __MAX_ALLOCA_CUTOFF)
+ abi_note = alloca (size);
+ else
+ {
+ /* There could be multiple PT_NOTEs. */
+ abi_note_malloced = realloc (abi_note_malloced, size);
+ if (abi_note_malloced == NULL)
+ goto read_error;
+
+ abi_note = abi_note_malloced;
+ }
__lseek (fd, ph->p_offset, SEEK_SET);
if (__libc_read (fd, (void *) abi_note, size) != size)
- goto read_error;
+ {
+ free (abi_note_malloced);
+ goto read_error;
+ }
}
while (memcmp (abi_note, &expected_note, sizeof (expected_note)))
break;
}
+ free (abi_note_malloced);
}
return fd;
--- /dev/null
+/* Bug 20419: test for stack overflow in elf/dl-load.c open_verify()
+ Copyright (C) 2018 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
+ <http://www.gnu.org/licenses/>. */
+
+/* This creates a .so with 8MiB PT_NOTE segment.
+ On a typical Linux system with 8MiB "ulimit -s", that was enough
+ to trigger stack overflow in open_verify. */
+
+.pushsection .note.big,"a"
+.balign 4
+.fill 8*1024*1024, 1, 0
+.popsection
--- /dev/null
+/* Bug 20419: test for stack overflow in elf/dl-load.c open_verify()
+ Copyright (C) 2018 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
+ <http://www.gnu.org/licenses/>. */
+
+/* This file must be run from within a directory called "elf". */
+
+int main (int argc, char *argv[])
+{
+ /* Nothing to do here: merely linking against tst-big-note-lib.so triggers
+ the bug. */
+ return 0;
+}