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authorDaniel Micay <danielmicay@gmail.com>2017-09-08 16:16:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-08 18:26:50 -0700
commit33d72f3822d7ff8a9e45bd7413c811085cb87aa5 (patch)
treeb55112ecf9eeff7be0a49072a99da6317c3a3787
parent121388a31362b0d3176dc1190ac8064b98a61b20 (diff)
init/main.c: extract early boot entropy from the passed cmdline
Feed the boot command-line as to the /dev/random entropy pool Existing Android bootloaders usually pass data which may not be known by an external attacker on the kernel command-line. It may also be the case on other embedded systems. Sample command-line from a Google Pixel running CopperheadOS.... console=ttyHSL0,115200,n8 androidboot.console=ttyHSL0 androidboot.hardware=sailfish user_debug=31 ehci-hcd.park=3 lpm_levels.sleep_disabled=1 cma=32M@0-0xffffffff buildvariant=user veritykeyid=id:dfcb9db0089e5b3b4090a592415c28e1cb4545ab androidboot.bootdevice=624000.ufshc androidboot.verifiedbootstate=yellow androidboot.veritymode=enforcing androidboot.keymaster=1 androidboot.serialno=FA6CE0305299 androidboot.baseband=msm mdss_mdp.panel=1:dsi:0:qcom,mdss_dsi_samsung_ea8064tg_1080p_cmd:1:none:cfg:single_dsi androidboot.slot_suffix=_b fpsimd.fpsimd_settings=0 app_setting.use_app_setting=0 kernelflag=0x00000000 debugflag=0x00000000 androidboot.hardware.revision=PVT radioflag=0x00000000 radioflagex1=0x00000000 radioflagex2=0x00000000 cpumask=0x00000000 androidboot.hardware.ddr=4096MB,Hynix,LPDDR4 androidboot.ddrinfo=00000006 androidboot.ddrsize=4GB androidboot.hardware.color=GRA00 androidboot.hardware.ufs=32GB,Samsung androidboot.msm.hw_ver_id=268824801 androidboot.qf.st=2 androidboot.cid=11111111 androidboot.mid=G-2PW4100 androidboot.bootloader=8996-012001-1704121145 androidboot.oem_unlock_support=1 androidboot.fp_src=1 androidboot.htc.hrdump=detected androidboot.ramdump.opt=mem@2g:2g,mem@4g:2g androidboot.bootreason=reboot androidboot.ramdump_enable=0 ro root=/dev/dm-0 dm="system none ro,0 1 android-verity /dev/sda34" rootwait skip_initramfs init=/init androidboot.wificountrycode=US androidboot.boottime=1BLL:85,1BLE:669,2BLL:0,2BLE:1777,SW:6,KL:8136 Among other things, it contains a value unique to the device (androidboot.serialno=FA6CE0305299), unique to the OS builds for the device variant (veritykeyid=id:dfcb9db0089e5b3b4090a592415c28e1cb4545ab) and timings from the bootloader stages in milliseconds (androidboot.boottime=1BLL:85,1BLE:669,2BLL:0,2BLE:1777,SW:6,KL:8136). [tytso@mit.edu: changelog tweak] [labbott@redhat.com: line-wrapped command line] Link: http://lkml.kernel.org/r/20170816231458.2299-3-labbott@redhat.com Signed-off-by: Daniel Micay <danielmicay@gmail.com> Signed-off-by: Laura Abbott <labbott@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Laura Abbott <lauraa@codeaurora.org> Cc: Nick Kralevich <nnk@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--init/main.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/init/main.c b/init/main.c
index ae5d1fd78081..0ee9c6866ada 100644
--- a/init/main.c
+++ b/init/main.c
@@ -530,8 +530,10 @@ asmlinkage __visible void __init start_kernel(void)
setup_arch(&command_line);
/*
* Set up the the initial canary and entropy after arch
+ * and after adding latent and command line entropy.
*/
add_latent_entropy();
+ add_device_randomness(command_line, strlen(command_line));
boot_init_stack_canary();
mm_init_cpumask(&init_mm);
setup_command_line(command_line);