The bufprint routine used by capi_cmsg2str does an unbounded vsprintf into a
8192 byte buffer, perhaps hoping it's big enough.
If the content of that vsprintf can be controlled by remote peers, this may lead
to a remote security hole for daemons using CAPI (pppd-capi-plugin,
asterisk-chan-capi, capi4hylafax, ...). Or a DoS.
If the content of that vsprintf can be controlled by local users making use of a
system service (such as sending a fax, making a phone call, ...) that uses CAPI,
this is a privilege escalation or remote authenticated user security hole, or a DoS.
Marcel, the exploit in bug 230563 comment #1 requires access to
/dev/capi20, which has permission 600 (and thus needs super-user
privileges). If that is our only exposure, please close this as
Created attachment 150897 [details]
patch for this BZ
Created attachment 150899 [details]
CVS repository patch, adds CONFIG_CAPI_TRACE option
Compilation is successful but not tested, because i do not have ISDN card available.
Patch still contains errors, please do not test it now.
Created attachment 151273 [details]
correct patch, only compilation tested, need to test with real hardware
fixed in build 2.4.21-51.EL
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.
*** Bug 402771 has been marked as a duplicate of this bug. ***