On Thu, Jul 6, 2017 at 1:48 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: > On Thu, 6 Jul 2017, Thomas Garnier wrote: >> On Wed, Jun 28, 2017 at 10:52 AM, Kees Cook <keescook@xxxxxxxxxxxx> wrote: >> > >> > On Tue, Jun 20, 2017 at 1:24 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote: >> > > On Wed, Jun 14, 2017 at 6:12 PM, Thomas Garnier <thgarnie@xxxxxxxxxx> wrote: >> > >> Ensure the address limit is a user-mode segment before returning to >> > >> user-mode. Otherwise a process can corrupt kernel-mode memory and elevate >> > >> privileges [1]. >> > >> >> > >> The set_fs function sets the TIF_SETFS flag to force a slow path on >> > >> return. In the slow path, the address limit is checked to be USER_DS if >> > >> needed. >> > >> >> > >> The addr_limit_user_check function is added as a cross-architecture >> > >> function to check the address limit. >> > >> >> > >> [1] https://bugs.chromium.org/p/project-zero/issues/detail?id=990 >> > >> >> > >> Signed-off-by: Thomas Garnier <thgarnie@xxxxxxxxxx> >> > > >> > > Thanks for reworking this series! >> > > >> > > The bad state correctly BUGs under the LKDTM test: >> > > >> > > [ 21.171586] lkdtm: Performing direct entry CORRUPT_USER_DS >> > > [ 21.172791] lkdtm: setting bad task size limit >> > > [ 21.173742] ------------[ cut here ]------------ >> > > [ 21.174641] kernel BUG at ./include/linux/syscalls.h:220! >> > > ... >> > > [ 21.193166] Call Trace: >> > > [ 21.193617] ? trace_hardirqs_on_thunk+0x1a/0x1c >> > > [ 21.194443] entry_SYSCALL64_slow_path+0x25/0x25 >> > > >> > > >> > > Tested-by: Kees Cook <keescook@xxxxxxxxxxxx> >> > >> > Is everyone happy with this patch for x86? Does this need anything >> > more/different? >> >> Asking again. Additional feedback? Anyone wants to pick-it up? > > Can do. This needs to be a combo of all 3 I assume as the x86 one contains > the function used by all of them, right? That is correct. > > Thanks, > > tglx -- Thomas -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
