[gnutls-devel] gnutls-3.3.10 SIGBUS on Solaris 10 in gettime()

[Thomas Thorberger]

Hello!

I found a bug on Solaris which crashes all applications using libgnutls 
with a SIGBUS in the function gettime() called by _rnd_get_event() 
[lib/nettle/rnd-common.c].

Environment:
   Solaris 10 (Oracle Solaris 10 1/13 s10s_u11wos_24a SPARC)
   Compiler: gcc (GCC) 4.9.2 (using Sun AS/LD)
   The compiler was generating code for the 64-bit environment.

GDB Output:

Program terminated with signal SIGBUS, Bus error.

(gdb) bt
#0  0xffffffff7d3dcedc in __clock_gettime () from /lib/64/libc.so.1
#1  0xffffffff7f011e34 in _rnd_get_event ()
    from /var/local/rpm/src/BUILD/gnutls-3.3.10/lib/.libs/libgnutls.so.28
#2  0xffffffff7f0125cc in wrap_nettle_rnd_init ()
    from /var/local/rpm/src/BUILD/gnutls-3.3.10/lib/.libs/libgnutls.so.28
#3  0xffffffff7ef6d968 in _gnutls_rnd_init ()
    from /var/local/rpm/src/BUILD/gnutls-3.3.10/lib/.libs/libgnutls.so.28
#4  0xffffffff7ef60120 in gnutls_global_init ()
    from /var/local/rpm/src/BUILD/gnutls-3.3.10/lib/.libs/libgnutls.so.28
#5  0xffffffff7ef60548 in lib_init ()
    from /var/local/rpm/src/BUILD/gnutls-3.3.10/lib/.libs/libgnutls.so.28
#6  0xffffffff7f012ebc in _init ()
    from /var/local/rpm/src/BUILD/gnutls-3.3.10/lib/.libs/libgnutls.so.28
#7  0xffffffff7f61831c in call_init () from /lib/sparcv9/ld.so.1
#8  0xffffffff7f617608 in setup () from /lib/sparcv9/ld.so.1
#9  0xffffffff7f629f04 in _setup () from /lib/sparcv9/ld.so.1
#10 0xffffffff7f60850c in _alias_start () from /lib/sparcv9/ld.so.1


The bug is triggered by the "__attribute__((packed))" in the structure 
definition of "struct event_st" in lib/nettle/rnd-common.h. If the 
"packed" attribute is active all references to the substructure "struct 
timespec" generate a SIGBUS. I guess that the alignment for a 64bit long 
falls below the minimum required alignment when using "packed" with 
"struct timespec".

I cannot tell you if this is specific to my environment or if it affects 
all Solaris Systems with the recent GCC generating a 64-bit version of 
libgnutls.

I attached the patch I used to get gnutls working again.

Regards,
   Thomas Thorberger


--- gnutls-3.3.10/lib/nettle/rnd-common.h.orig  2014-11-12 
13:37:43.916658427 +0100
+++ gnutls-3.3.10/lib/nettle/rnd-common.h       2014-11-12 
13:40:56.636814380 +0100
@@ -42,7 +42,7 @@
                 unsigned count; /* a running counter */
                 unsigned err; /* the last errno */
  }
-#ifdef __GNUC__
+#if defined(__GNUC__) && !defined(__sun)
  __attribute__((packed))
  #endif
  ;