I've "fixed" the problem by adding a section in the PROBLEMS file. I
see no reason to support a buggy compiler by changing the OpenSSL code.
Ths ticket is now resolved.
[[EMAIL PROTECTED] - Tue Dec 3 14:17:08 2002]:
> Seeing the "bugs" directory in the openssl tarball, I thought you
> might be interested to know that gcc-3.0 contains a bug that is
> triggered in the PEM_get_EVP_CIPHER_INFO() function...
>
> Here is the problem:
>
> $ ssh-keygen -t rsa -N abcde
> then
> $ ssh-keygen -t rsa -P abcde -p
>
> should works, but it didn't on my system (gcc-3.0, OpenSSH_3.4p1,
> OpenSSL 0x00907004).
>
> I have traced down the problem to PEM_get_EVP_CIPHER_INFO(): gcc-3.0
> generates invalid assembler for this function. Just look at the
machine
> code that corresponds to this C code:
>
> header+=11;
> if (*header != '4') return(0); header++;
> if (*header != ',') return(0); header++;
>
> And you will notice that %eax (that represents "header") is
incremented
> too many times...
>
> A more insightful demonstration of this bug is also available in the
> `gcc-3.0-bug-demo.c' file.
>
> ----------------------------------------------------------------------
> /*
> ** Gcc-3.0 bug -- noticed by Marc Bevand <bevand_m (at) epita.fr>
> ** on Tue Dec 3 14:06:02 CET 2002
> **
> ** All is right with "-fPIC -O1", the bug only occurs with "-fPIC
> ** -O[23]":
> **
> ** $ gcc -fPIC -O1 gcc-3.0-bug-demo.c
> ** $ ./a.out
> ** all is right
> ** $ gcc -fPIC -O2 gcc-3.0-bug-demo.c
> ** $ ./a.out
> ** there is a *bug*
> **
> ** Look at the assembler generated for the 2 lines marked with XXX in
> ** foobar():
> **
> ** 80484e3: 8b 45 08 mov 0x8(%ebp),%eax
> ** 80484e6: 83 c0 02 add $0x2,%eax
> ** 80484e9: 89 45 08 mov %eax,0x8(%ebp)
> ** 80484ec: 80 78 02 63 cmpb $0x63,0x2(%eax)
> **
> ** The value of "header", contained in 0x8(%ebp), should be
incremented
> ** only 1 time, but actually it is incremented 2 times (in add and
> ** cmpb).
> */
>
> int hello(char **notused)
> {
> return 0;
> }
>
> int foobar(char *header)
> {
> if (strncmp(header, "ab", 2))
> return 0;
> header += 2; /* XXX */
> if (*header != 'c') /* XXX */
> return 0;
> if (hello(&header))
> return 0;
> return 1;
> }
>
> int main(void)
> {
> if (foobar("abc__"))
> puts("all is right");
> else
> puts("there is a *bug*");
> return 0;
> }
> ----------------------------------------------------------------------
--
Richard Levitte
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