diff options
| -rw-r--r-- | sysdeps/x86_64/Makefile | 8 | ||||
| -rw-r--r-- | sysdeps/x86_64/dl-machine.h | 5 | ||||
| -rw-r--r-- | sysdeps/x86_64/tst-plt-rewrite2.c | 46 | ||||
| -rw-r--r-- | sysdeps/x86_64/tst-plt-rewritemod2.c | 32 |
4 files changed, 89 insertions, 2 deletions
diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile index 374bca80d0..836e03a224 100644 --- a/sysdeps/x86_64/Makefile +++ b/sysdeps/x86_64/Makefile @@ -186,9 +186,11 @@ endif ifeq (yes,$(have-z-mark-plt)) tests += \ tst-plt-rewrite1 \ + tst-plt-rewrite2 \ # tests modules-names += \ tst-plt-rewritemod1 \ + tst-plt-rewritemod2 \ # modules-names tst-plt-rewrite1-no-pie = yes @@ -200,6 +202,12 @@ $(objpfx)tst-plt-rewrite1.out: /dev/null $(objpfx)tst-plt-rewrite1 $(tst-plt-rewrite1-ENV) $(make-test-out) > $@ 2>&1; \ grep -q -E "changing 'bar' PLT entry in .*/elf/tst-plt-rewritemod1.so' to direct branch" $@; \ $(evaluate-test) + +tst-plt-rewrite2-no-pie = yes +LDFLAGS-tst-plt-rewrite2 = -Wl,-z,now +LDFLAGS-tst-plt-rewritemod2.so = -Wl,-z,now,-z,undefs +tst-plt-rewrite2-ENV = GLIBC_TUNABLES=glibc.cpu.plt_rewrite=2 +$(objpfx)tst-plt-rewrite2: $(objpfx)tst-plt-rewritemod2.so endif endif # $(subdir) == elf diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h index ca290ef082..2d2ce503a5 100644 --- a/sysdeps/x86_64/dl-machine.h +++ b/sysdeps/x86_64/dl-machine.h @@ -607,8 +607,9 @@ x86_64_rewrite_plt (struct link_map *map, ElfW(Addr) plt_rewrite) /* Skip ENDBR64 if IBT isn't enabled. */ if (!ibt_enabled_p) branch_start = ALIGN_DOWN (branch_start, pltent); - /* Get the displacement from the branch target. */ - ElfW(Addr) disp = value - branch_start - JMP32_INSN_SIZE; + /* Get the displacement from the branch target. NB: We must use + 64-bit integer on x32 to avoid overflow. */ + uint64_t disp = (uint64_t) value - branch_start - JMP32_INSN_SIZE; ElfW(Addr) plt_end; ElfW(Addr) pad; diff --git a/sysdeps/x86_64/tst-plt-rewrite2.c b/sysdeps/x86_64/tst-plt-rewrite2.c new file mode 100644 index 0000000000..8427df5605 --- /dev/null +++ b/sysdeps/x86_64/tst-plt-rewrite2.c @@ -0,0 +1,46 @@ +/* Test PLT rewrite with 32-bit displacement overflow. + 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 + <https://www.gnu.org/licenses/>. */ + +#include <support/check.h> + +extern int (*func_p) (void); +extern void foo (void); + +int +func (void) +{ + return 0xbadbeef; +} + +void +bar (void) +{ + TEST_VERIFY (func_p == &func); + TEST_VERIFY (func_p () == 0xbadbeef); +} + +static int +do_test (void) +{ + func_p = &func; + foo (); + bar (); + return 0; +} + +#include <support/test-driver.c> diff --git a/sysdeps/x86_64/tst-plt-rewritemod2.c b/sysdeps/x86_64/tst-plt-rewritemod2.c new file mode 100644 index 0000000000..4a86d736b5 --- /dev/null +++ b/sysdeps/x86_64/tst-plt-rewritemod2.c @@ -0,0 +1,32 @@ +/* Check PLT rewrite with 32-bit displacement overflow. + 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 + <https://www.gnu.org/licenses/>. */ + +/* foo calls func with indirect branch via PLT. PLT rewrite shouldn't + change it to direct branch if func is too far way. */ + +#include <support/check.h> + +int (*func_p) (void); +extern int func (void); + +void +foo (void) +{ + TEST_VERIFY (func () == 0xbadbeef); + TEST_VERIFY (func_p () == 0xbadbeef); +} |