On 10/01/2013 01:26 PM, Djalal Harouni wrote: > /proc/<pid>/* entries varies at runtime, appropriate permission checks > need to happen during each system call. > > Currently some of these sensitive entries are protected by performing > the ptrace_may_access() check. However even with that the /proc file > descriptors can be passed to a more privileged process > (e.g. a suid-exec) which will pass the classic ptrace_may_access() > check. In general the ->open() call will be issued by an unprivileged > process while the ->read(),->write() calls by a more privileged one. > > Example of these files are: > /proc/*/syscall, /proc/*/stack etc. > > And any open(/proc/self/*) then suid-exec to read()/write() /proc/self/* > > > These files are protected during read() by the ptrace_may_access(), > however the file descriptor can be passed to a suid-exec which can be > used to read data and bypass ASLR. Of course this was discussed several > times on LKML. Can you elaborate on what it is that you're fixing? That is, can you give a concrete example of what process opens what file and passes the fd to what process? I'm having trouble following your description. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
