> On 22 Dec 2018, at 18:28, Hauke Mehrtens <[email protected]> wrote: > > > Hi Yousong, > > ASLR is currently not activated by default in OpenWrt, so the binary itself > is not randomized. Activate CONFIG_PKG_ASLR_PIE to compile Openwrt with ASLR, > but this increases the size of the binary. > > I haven't understood why some parts of the busybox binary and other binaries > are mapped rwx, when I look into it with readelf no section is mapped rwx, > but it looks like some sections are ending at an not page aligned offset and > the next section starts directly after that. I assume that Linux merges the > permissions when one page needs different permissions. > > I am still not sure if the common mips CPUs (24Kec, 74Kec) support > restricting execution on pages anyway. > > Huake
At the risk of going further down the rabbit hole/off topic, if you set the cpu_has_rixi to 1 in target/linux/ath79/patches-4.14/0014-MIPS-ath79-finetune-cpu-overrides.patch and with PKG_ASLR_PIE [=y] you get: cat /proc/self/maps 00400000-0047a000 r-xp 00000000 1f:03 1825 /bin/busybox 00489000-0048a000 r--p 00079000 1f:03 1825 /bin/busybox 0048a000-0048b000 rw-p 0007a000 1f:03 1825 /bin/busybox 77e38000-77e5d000 r-xp 00000000 1f:03 2298 /lib/libgcc_s.so.1 77e5d000-77e5e000 rw-p 00015000 1f:03 2298 /lib/libgcc_s.so.1 77e5e000-77ef1000 r-xp 00000000 1f:03 2474 /lib/libc.so 77f00000-77f02000 rw-p 00092000 1f:03 2474 /lib/libc.so 77f02000-77f04000 rw-p 00000000 00:00 0 7f9bd000-7f9de000 rw-p 00000000 00:00 0 [stack] 7fefb000-7fefc000 r-xp 00000000 00:00 0 7ff68000-7ff69000 r--p 00000000 00:00 0 [vvar] 7ff69000-7ff6a000 r-xp 00000000 00:00 0 [vdso] The archer hasn’t blown up…….yet Cheers, Kevin D-B 012C ACB2 28C6 C53E 9775 9123 B3A2 389B 9DE2 334A _______________________________________________ openwrt-devel mailing list [email protected] https://lists.openwrt.org/mailman/listinfo/openwrt-devel
