| Message ID | 20161128123228.30856-9-nix@esperi.org.uk |
|---|---|
| State | New |
| Headers | show |
On 11/28/2016 01:32 PM, Nix wrote: > From: Adhemerval Zanella <adhemerval.zanella@linaro.org> > > We use the same assembler-macro trick we use to de-PLTize > compiler-generated libcalls to memcpy and memset to redirect > __stack_chk_fail to __stack_chk_fail_local. > > v5: New. > v6: Only do it within the shared library: with __stack_chk_fail_local > in libc_pic.a now we don't need to worry about calls from inside > other routines in libc_nonshared.a any more. > v8: Merge #ifdef blocks. > > * sysdeps/generic/symbol-hacks.h (__stack_chk_fail): Add internal > alias. > --- > sysdeps/generic/symbol-hacks.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/sysdeps/generic/symbol-hacks.h b/sysdeps/generic/symbol-hacks.h > index ce576c9..36908b5 100644 > --- a/sysdeps/generic/symbol-hacks.h > +++ b/sysdeps/generic/symbol-hacks.h > @@ -4,4 +4,8 @@ > asm ("memmove = __GI_memmove"); > asm ("memset = __GI_memset"); > asm ("memcpy = __GI_memcpy"); > + > +/* -fstack-protector generates calls to __stack_chk_fail, which need > + similar adjustments to avoid going through the PLT. */ > +asm ("__stack_chk_fail = __stack_chk_fail_local"); > #endif We should do this only if we compile glibc with stack protector support enabled, and disable this for the files which we compile without stack protector. I hope this will fix an assembler error while compiling __stack_chk_fail.c on ia64: /tmp/ccCNZVJs.s:51: Error: `__stack_chk_fail' was not defined within procedure /tmp/ccCNZVJs.s:51: Warning: `__stack_chk_fail#' was not specified with previous .proc /tmp/ccCNZVJs.s:51: Warning: `__stack_chk_fail' should be an operand to this .endp The .s file looks like this: 1 .file "stack_chk_fail.c" 2 .pred.safe_across_calls p1-p5,p16-p63 3 .text 4 .Ltext0: 5 #APP 6 memmove = __GI_memmove 7 memset = __GI_memset 8 memcpy = __GI_memcpy 9 __stack_chk_fail = __stack_chk_fail_local 10 .section .rodata.str1.8,"aMS",@progbits,1 11 .align 8 12 .LC0: 13 stringz "stack smashing detected" 14 #NO_APP 15 .text 16 .align 16 17 .align 64 18 .global __stack_chk_fail# 19 .type __stack_chk_fail#, @function 20 .proc __stack_chk_fail# 21 __stack_chk_fail: 22 [.LFB33:] 23 .file 1 "stack_chk_fail.c" 24 .loc 1 27 0 25 .prologue 12, 32 26 .mib 27 .save ar.pfs, r33 28 alloc r33 = ar.pfs, 0, 3, 1, 0 29 [.LCFI0:] 30 .save rp, r32 31 mov r32 = b0 32 [.LCFI1:] 33 .loc 1 28 0 34 nop 0 35 .mlx 36 nop 0 37 movl r35 = @gprel(.LC0) 38 .loc 1 27 0 39 .body 40 .loc 1 28 0 41 ;; 42 .mib 43 nop 0 44 add r35 = r1, r35 45 br.call.sptk.many b0 = __GI___fortify_fail 46 [.LVL0:] 47 ;; 48 break.f 0 49 ;; 50 .LFE33: 51 .endp __stack_chk_fail# Thanks, Florian
diff --git a/sysdeps/generic/symbol-hacks.h b/sysdeps/generic/symbol-hacks.h index ce576c9..36908b5 100644 --- a/sysdeps/generic/symbol-hacks.h +++ b/sysdeps/generic/symbol-hacks.h @@ -4,4 +4,8 @@ asm ("memmove = __GI_memmove"); asm ("memset = __GI_memset"); asm ("memcpy = __GI_memcpy"); + +/* -fstack-protector generates calls to __stack_chk_fail, which need + similar adjustments to avoid going through the PLT. */ +asm ("__stack_chk_fail = __stack_chk_fail_local"); #endif
From: Adhemerval Zanella <adhemerval.zanella@linaro.org> We use the same assembler-macro trick we use to de-PLTize compiler-generated libcalls to memcpy and memset to redirect __stack_chk_fail to __stack_chk_fail_local. v5: New. v6: Only do it within the shared library: with __stack_chk_fail_local in libc_pic.a now we don't need to worry about calls from inside other routines in libc_nonshared.a any more. v8: Merge #ifdef blocks. * sysdeps/generic/symbol-hacks.h (__stack_chk_fail): Add internal alias. --- sysdeps/generic/symbol-hacks.h | 4 ++++ 1 file changed, 4 insertions(+)