Bug#678353: Backtrace

[Benjamin Eikel]

Hello,

I have build the openssl source package with DEB_BUILD_OPTIONS="nostrip
noopt nohardening". With gdb, I have set a breakpoint in s3_pkt.c:484. When
the execution stops there, the backtrace is:

#0 0x00007ffff7f9095b in ssl3_get_record () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
#1 0x00007ffff7f918a4 in ssl3_read_bytes () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
#2 0x00007ffff7f8d77f in ssl3_read_internal () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
#3 0x00007ffff7f8d82e in ssl3_read () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
#4 0x00007ffff7fb05b8 in SSL_read () from /usr/lib/x86_64-linux-gnu/libssl.so.1.0.0
#5 0x0000000000449ce4 in s_client_main ()
#6 0x000000000041959b in do_cmd ()
#7 0x000000000041917c in main ()

I think that the backtrace will not be very helpful. Does it help if I send
the output produced by s_client -debug ...?

Strangely debugging does not fully work. The code is found:
(gdb) list s3_pkt.c:484
479 * SSL 3.0 only has 'bad_record_mac'. But unless a decryption
480 * failure is directly visible from the ciphertext anyway,
481 * we should not reveal which kind of error occured -- this
482 * might become visible to an attacker (e.g. via a logfile) */
483 al=SSL_AD_BAD_RECORD_MAC;
484 SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
485 goto f_err;
486 }
487
488 /* r->length is now just compressed */

But "print al", for example, does not work. In the backtrace, files and line
numbers are missing. I also tried to give "debug-linux-x86_64" to ./Configure
in debian/rules, but this does not help. Do you know why there is debugging
information missing? What should I do to get more information to find the
source of the bug?

Kind regards
Benjamin


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