Date: Sun, 08 Jun 2014 23:36:45 +0000 From: bz-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 121073] [kernel] [patch] run chroot as an unprivileged user Message-ID: <bug-121073-8-1wJ45O4hNY@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-121073-8@https.bugs.freebsd.org/bugzilla/> References: <bug-121073-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=121073 --- Comment #7 from Jille@quis.cx --- I remember someone saying this could be exploited using rfork. I don't know why it's not listed in this bug. IIRC the problem was that fd_rdir (root of the processes) was stored in proc->p_fd (struct filedesc) and the P_NOSUGID-flag in struct proc itself. One could use rfork to create a new process with the same descriptor table and call chroot in the child which would flag the child with P_NOSUGID but change to root for the parent as well. The parent doesn't get P_NOSUGID however and will be able to execve a setuid executable with a fake libc. -- You are receiving this mail because: You are the assignee for the bug.
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