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From:	RayeR <glaux AT centrum DOT cz>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Does DJGPP GCC support SSP stack protection?
Date:	Fri, 4 Dec 2009 04:03:30 -0800 (PST)
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Yeah,
I just need "-lssp" arg to gcc to link libssp.a
so now compiled with
gcc -Wall -fstack-protector -o head.exe head.c -lssp
is OK. I tried to jamm the stack little bit.

Here's result with standard compiling:

Exiting due to signal SIGSEGV
Stack Fault at eip=000016d9
eax=00000000 ebx=0000029e ecx=30580000 edx=00000035 esi=00000054
edi=0001266c
ebp=266c0009 esp=3057fffc program=C:\DJGPP\C\HEAD.EXE
cs: sel=01a7  base=029e0000  limit=0009ffff
ds: sel=01af  base=029e0000  limit=0009ffff
es: sel=01af  base=029e0000  limit=0009ffff
fs: sel=017f  base=00005c20  limit=0000ffff
gs: sel=01bf  base=00000000  limit=0010ffff
ss: sel=01af  base=029e0000  limit=0009ffff
App stack: [00092668..0001266c]  Exceptn stack: [000125ac..0001066c]

Call frame traceback EIPs:
  0x000016d9

and here with SSP enabled:

*** stack smashing detected ***:  terminated
 Exiting due to signal SIGILL
Invalid Opcode at eip=000017a4
eax=00000000 ebx=00000000 ecx=0001505c edx=0009a8a8 esi=00099970
edi=00000005
ebp=000999e8 esp=00099970 program=C:\DJGPP\C\HEAD.EXE
cs: sel=01a7  base=029e0000  limit=0009ffff
ds: sel=01af  base=029e0000  limit=0009ffff
es: sel=01af  base=029e0000  limit=0009ffff
fs: sel=017f  base=00005c20  limit=0000ffff
gs: sel=01bf  base=00000000  limit=0010ffff
ss: sel=01af  base=029e0000  limit=0009ffff
App stack: [00099a68..00019a68]  Exceptn stack: [00019978..00017a38]

Call frame traceback EIPs:
  0x000017a4
  0x00001617
  0x000016e9
  0x0000332f

Now in this simple case it seems that standard memory protection is
enough to detect a problem..

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