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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2022-10-05 14:07:28 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2022-10-06 12:52:46 -0300 |
| commit | e82aab227bdf3faa0f28a69dbf50b5562659d1cf (patch) | |
| tree | be705a9dbf78497d4a108f165bddc54b8eef9bc6 | |
| parent | 90d58fe8442fb2f79cab88c07af91c9eae59419a (diff) | |
| download | glibc-e82aab227bdf3faa0f28a69dbf50b5562659d1cf.zip glibc-e82aab227bdf3faa0f28a69dbf50b5562659d1cf.tar.gz glibc-e82aab227bdf3faa0f28a69dbf50b5562659d1cf.tar.bz2 | |
csu: Disable stack protector for static-reloc for static-pie
For instance on x86_64 with gcc 12.1.1 andwith fstack-protector
enabled the empty function still generates a stack protector code
sequence:
0000000000000000 <_dl_relocate_static_pie>:
0: 48 83 ec 18 sub $0x18,%rsp
4: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax
b: 00 00
d: 48 89 44 24 08 mov %rax,0x8(%rsp)
12: 31 c0 xor %eax,%eax
14: 48 8b 44 24 08 mov 0x8(%rsp),%rax
19: 64 48 2b 04 25 28 00 sub %fs:0x28,%rax
20: 00 00
22: 75 05 jne 29 <_dl_relocate_static_pie+0x29>
24: 48 83 c4 18 add $0x18,%rsp
28: c3 ret
29: e8 00 00 00 00 call 2e <_dl_relocate_static_pie+0x2e>
And since the function is called prior thread pointer setup, it
triggers a invalid memory access (this is shown with the failure
of elf/tst-tls1-static-non-pie).
Although it might characterizes as compiler issue or missed
optimization, to be safe also disables stack protector on
static-reloc object.
Checked on x86_64-linux-gnu and sparc64-linux-gnu.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
| -rw-r--r-- | csu/Makefile | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/csu/Makefile b/csu/Makefile index 2e8a28e..f71a5eb 100644 --- a/csu/Makefile +++ b/csu/Makefile @@ -50,15 +50,21 @@ tests = # applications, so that build flags matter. # See <https://sourceware.org/ml/libc-alpha/2018-07/msg00101.html>. # +# The function is called prior the thread pointer setup, and if stack +# protector is enabled the compiler might still generate the stack check +# (which requires the thread pointer correctly set). +extra-no-ssp = static-reloc + # libc-start.os is safe to be built with stack protector since # __libc_start_main is called after stack canary setup is done. -ssp-safe.os = static-reloc libc-start +ssp-safe.os = libc-start -CFLAGS-.o += $(call elide-stack-protector,.o,$(routines)) -CFLAGS-.op += $(call elide-stack-protector,.op,$(routines)) -CFLAGS-.oS += $(call elide-stack-protector,.oS,$(routines)) +CFLAGS-.o += $(call elide-stack-protector,.o,$(routines) $(extra-no-ssp)) +CFLAGS-.op += $(call elide-stack-protector,.op,$(routines) $(extra-no-ssp)) +CFLAGS-.oS += $(call elide-stack-protector,.oS,$(routines) $(extra-no-ssp)) CFLAGS-.os += $(call elide-stack-protector,.os,$(filter-out \ - $(ssp-safe.os),$(routines))) + $(ssp-safe.os), \ + $(routines) $(extra-no-ssp))) ifeq (yes,$(build-shared)) extra-objs += S$(start-installed-name) gmon-start.os |