app_sms: BufferOverflow when receiving odd length 16 bit message

This patch prevents an infinite loop overwriting memory when
a message is received into the unpacksms16() function, where
the length of the message is an odd number of bytes.

(closes issue ASTERISK-22590)
Reported by: Jan Juergens
Tested by: Jan Juergens


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@403856 f38db490-d61c-443f-a65b-d21fe96a405b
pbx.c: put copy of ast_exten.data on stack to prevent memory corruption

During dialplan execution in pbx_extension_helper(), the contexts global
read lock prevents link list corruption, but was released with a pointer
to the ast_exten and data later used in variable substitution.  Instead,
this patch removes pbx_substitute_variables() and locates a copy of the
ast_exten data on the stack before releasing the lock, where ast_exten
could get free'd by another thread performing a module reload.

(issue AST-1179)
Reported by: Thomas Arimont
(issue AST-1246)
Reported by: Alexander Hömig
........

Merged revisions 403862 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 403863 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@403864 f38db490-d61c-443f-a65b-d21fe96a405b