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Re: Fwd: VSFTPD Remote Heap Overrun (low severity)


From: Daniel J Walsh <dwalsh () redhat com>
Date: Mon, 12 Dec 2011 12:13:30 -0500

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On 12/12/2011 11:58 AM, Ramon de C Valle wrote:


Ramon, not sure I understand, what are you trying to prevent
here?
Hello Dan, vsftpd processes open locale files from the
"/usr/share/zoneinfo" directory, which are expected to have the
"locale_t" type. A chrooted user can create a specially-crafted
locale file in "/home/<user>/usr/share/zoneinfo" directory to try
exploiting this glibc vulnerability. However, the specially-crafted
locale file created will have the "user_home_t" type and not the
"locale_t". SELinux rules for vsftpd (i.e. ftpd_t) allowing only
opening locale files from "usr_t" directories with "locale_t" type
should have completely mitigated this.

But how can I state that ftp has access to the users homedir and not
allow access to user_home_t?
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