I've just compiled and installed openssh-2.9.9p2 (compiled against
openssl-0.9.6b using gcc-3.0.0) on a Slackware 7-based Linux machine
(kernel 2.4.6ac2). The previously installed version was 2.9p2, compiled
against openssl-0.9.6a, also with gcc-3.0.0, but with a different build of
gcc-3.0.0.
Everything seems to work fine except for one problem: passphrase matching
for ssh2 keys *always* fails. I've run ssh-add under gdb several times
trying to see what's going wrong, so far without learning anything
particularly enlightening.
Has anyone else encountered this problem? I have a possible theory that
it's compiler-related, but I haven't been able to verify the theory yet.
(My previous gcc-3.0.0 was compiled with gcc-2.95.3, while the current one
was compiled with a gcc-3.0.1 installation that I subsequently backed out
after discovering it wouldn't compile a kernel. Although I did a full
3-stage bootstrap when I rebuilt 3.0.0, I beginning to wonder whether I
still somehow got a subtly bad build.)
--
Linux Now! .........Because friends don't let friends use Microsoft.
phil stracchino :: alaric at babcom.com :: halmayne at sourceforge.net
unix ronin :::: renaissance man :::: mystic zen biker geek
2000 CBR929RR, 1991 VFR750F3 (foully murdered), 1986 VF500F (sold)
On Thu, 27 Sep 2001, Phil Stracchino wrote:> > I've just compiled and installed openssh-2.9.9p2 (compiled against > openssl-0.9.6b using gcc-3.0.0) on a Slackware 7-based Linux machine > (kernel 2.4.6ac2). The previously installed version was 2.9p2, compiled > against openssl-0.9.6a, also with gcc-3.0.0, but with a different build of > gcc-3.0.0. > > Everything seems to work fine except for one problem: passphrase matching > for ssh2 keys *always* fails. I've run ssh-add under gdb several times > trying to see what's going wrong, so far without learning anything > particularly enlightening.Are you using ssh-askpass or entering the passphrase from a tty? -d -- | Damien Miller <djm at mindrot.org> \ ``E-mail attachments are the poor man's | http://www.mindrot.org / distributed filesystem'' - Dan Geer
On Thu, Sep 27, 2001 at 02:26:14PM -0700, Phil Stracchino wrote:> I've just compiled and installed openssh-2.9.9p2 (compiled against > openssl-0.9.6b using gcc-3.0.0) on a Slackware 7-based Linux machine > (kernel 2.4.6ac2). The previously installed version was 2.9p2, compiled > against openssl-0.9.6a, also with gcc-3.0.0, but with a different build of > gcc-3.0.0. > > Everything seems to work fine except for one problem: passphrase matching > for ssh2 keys *always* fails. I've run ssh-add under gdb several times > trying to see what's going wrong, so far without learning anything > particularly enlightening.I have finally managed to isolate this down to the following: For SSH2 DSA and RSA keys, the OpenSSL PEM_read_PrivateKey() macro, called from authfile.c line 448: pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase); is consistently failing and always returns NULL, whereas it should be returning a EVP_PKEY struct with pk->type containing either EVP_PKEY_RSA or EVP_PKEY_DSA. As far as I can see from the OpenSSL code, this means that BIO_new(BIO_s_file()) has to be returning NULL, but that's as far as I can figure it out; the internals of OpenSSL are utterly impenetrable to me. Any suggestions, anyone? I think I've taken this problem about as far as I can diagnose it myself. OpenSSL was configured using the following options: --prefix=/usr shared threads -D_REENTRANT. Recompiling with no-threads out of constructive paranoia made no difference. OpenSSH was configured with: configure --prefix=/usr --with-tcp-wrappers --with-md5-passwords --with-ipv4-default --sysconfdir=/etc The same key files are handled correctly on a Solaris 2.8 machine with the same OpenSSL and OpenSSH versions, configured identically except for no --with-md5-passwords because Solaris still doesn't support md5crypt. Bad Sun, bad. No donut. -- Linux Now! .........Because friends don't let friends use Microsoft. phil stracchino :: alaric at babcom.com :: halmayne at sourceforge.net unix ronin :::: renaissance man :::: mystic zen biker geek 2000 CBR929RR, 1991 VFR750F3 (foully murdered), 1986 VF500F (sold)
On Fri, Sep 28, 2001 at 11:00:25AM -0700, Phil Stracchino wrote:> On Fri, Sep 28, 2001 at 06:21:26PM +0100, Dr S N Henson wrote: > > Read the bit in the FAQ about adding an ERR_print_errors_fp() call then > > see what it says is the cause.I tried using ERR_print_errors_fp() in the appropriate location and it reported nothing. I therefore took a slightly different tack. I changed the error detection code in key_load_private_pem() in authfile.c from this: pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase); if (pk == NULL) { debug("PEM_read_PrivateKey failed"); (void)ERR_get_error(); } else if (pk->type == EVP_PKEY_RSA && .... to this: pk = PEM_read_PrivateKey(fp, NULL, NULL, (char *)passphrase); if (pk == NULL) { error("PEM_read_PrivateKey failed"); while (ERR_peek_error()) error("PEM error %ld: %s", ERR_peek_error(), ERR_error_string(ERR_get_error(), NULL)); } else if (pk->type == EVP_PKEY_RSA && .... Right up to the point at which that PEM_read_PrivateKey() call is executed, everything appears to be working perfectly. At the moment of making this call: filename is "/root/.ssh/id_dsa" passphrase contains the correct password fp is valid, and _IO_read_base points at the string: "-----BEGIN DSA PRIVATE KEY-----\nProc-Type: 4,ENCRYPTED\n DEK-Info: DES-EDE3-CBC,<data....>" The passphrase supplied is known to be correct, and successfully unlocks this keyfile on a Solaris 8 machine which is running the same version of both OpenSSH and OpenSSL. Nevertheless, PEM_read_PrivateKey returns NULL, but according to ERR_peek_error(), no error has occurred. I am unable to trace into the PEM_read_PrivateKey() call using gdb. -- Linux Now! .........Because friends don't let friends use Microsoft. phil stracchino :: alaric at babcom.com :: halmayne at sourceforge.net unix ronin :::: renaissance man :::: mystic zen biker geek 2000 CBR929RR, 1991 VFR750F3 (foully murdered), 1986 VF500F (sold)
Phil Stracchino
2001-Sep-29 07:58 UTC
SOLVED: ssh2 key passphrase problems in 2.9.9 on Linux
On Fri, Sep 28, 2001 at 06:10:43PM -0700, Phil Stracchino wrote:> On Sat, Sep 29, 2001 at 01:22:59AM +0100, Dr S N Henson wrote: > > This is starting to look like a compiler bug. > > I've been suspecting that myself. The curious thing is that OpenSSH 2.9p2 > and OpenSSL 0.9.6a were working fine.Compiler bug it is. I haven't yet managed to rebuild a gcc-2.95,3, but I installed an old egcs-1.1.2 (gcc-2.91.66) and recompiled OpenSSL and OpenSSH with that, and suddenly it all worked. There was one minor quirk: 'ssh-agent > file' no longer produced any output to <file>. However, 'VAR=`ssh-agent`; echo $VAR > file' worked fine. Go figure. I then recompiled OpenSSH-2.9.9 with gcc-3.0, and that worked fine, and the ssh-agent > file quirk vanished. Go figure. So, be it officially known: gcc-3.0 will NOT correctly compile OpenSSL v0.9.6 on Linux, but compiles OpenSSH 2.9.9 without any problems against a known-good OpenSSL installation. -- Linux Now! .........Because friends don't let friends use Microsoft. phil stracchino :: alaric at babcom.com :: halmayne at sourceforge.net unix ronin :::: renaissance man :::: mystic zen biker geek 2000 CBR929RR, 1991 VFR750F3 (foully murdered), 1986 VF500F (sold)