Am 29.11.2015 um 00:00 schrieb Mickaël Salaün: > > > On 28/11/2015 23:55, Richard Weinberger wrote: >> Am 28.11.2015 um 23:52 schrieb Mickaël Salaün: >>> >>> On 28/11/2015 22:40, Richard Weinberger wrote: >>>> Am 28.11.2015 um 22:32 schrieb Mickaël Salaün: >>>>> Replace the default insecure mode 0777 with 0700 for temporary file. >>>>> >>>>> Prohibit other users to change the executable mapped code. >>>> >>>> Hmm, isn't the tmp file already unlinked at this stage? >>>> >>> >>> Yes, but if someone could open it before the unlink e.g. because of the >>> umask (which does not seems to be the case thanks to mkstemp, but remains >>> unspecified [1]), this user should then be able to have write access to the >>> file descriptor/description. >> >> Yes, someone can open it before the unlink. But you change the file mode >> after that. >> How does it improve the situation? The attacker has already the file handle. > > The attacker could have the file handle only in a read-only mode, which is a > bit different than being able to write and execute arbitrary code thanks to a > file descriptor mapped RWX :)
Fair point. Please describe this in detail in the patch changelog. :-) Thanks, //richard ------------------------------------------------------------------------------ _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
