* [PATCHv2 0/2] Command line randomness @ 2017-08-16 22:46 Laura Abbott 2017-08-16 22:46 ` [PATCHv2 1/2] init: Move stack canary initialization after setup_arch Laura Abbott 2017-08-16 22:46 ` [PATCHv2 2/2] extract early boot entropy from the passed cmdline Laura Abbott 0 siblings, 2 replies; 9+ messages in thread From: Laura Abbott @ 2017-08-16 22:46 UTC (permalink / raw) To: Kees Cook Cc: Laura Abbott, kernel-hardening, linux-kernel, linux-mm, Andrew Morton, Daniel Micay Hi, This is a series to add the kernel command line as a source of randomness. The first patch is an (old) prepatory patch from me to move the stack canary initialization later. The second patch is from Daniel Micay to actually add the command line to the pool. Kees suggested this go through -mm. Thanks, Laura Daniel Micay (1): extract early boot entropy from the passed cmdline Laura Abbott (1): init: Move stack canary initialization after setup_arch init/main.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) -- 2.13.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCHv2 1/2] init: Move stack canary initialization after setup_arch 2017-08-16 22:46 [PATCHv2 0/2] Command line randomness Laura Abbott @ 2017-08-16 22:46 ` Laura Abbott 2017-08-16 22:50 ` Kees Cook 2017-08-16 22:46 ` [PATCHv2 2/2] extract early boot entropy from the passed cmdline Laura Abbott 1 sibling, 1 reply; 9+ messages in thread From: Laura Abbott @ 2017-08-16 22:46 UTC (permalink / raw) To: Kees Cook Cc: Laura Abbott, kernel-hardening, linux-kernel, linux-mm, Andrew Morton, Daniel Micay, Laura Abbott From: Laura Abbott <lauraa@codeaurora.org> Stack canary intialization involves getting a random number. Getting this random number may involve accessing caches or other architectural specific features which are not available until after the architecture is setup. Move the stack canary initialization later to accomodate this. Signed-off-by: Laura Abbott <lauraa@codeaurora.org> Signed-off-by: Laura Abbott <labbott@redhat.com> --- v2: Also moved add_latent_entropy per suggestion of Kees. --- init/main.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/init/main.c b/init/main.c index 052481fbe363..21d599eaad06 100644 --- a/init/main.c +++ b/init/main.c @@ -515,12 +515,6 @@ asmlinkage __visible void __init start_kernel(void) smp_setup_processor_id(); debug_objects_early_init(); - /* - * Set up the initial canary ASAP: - */ - add_latent_entropy(); - boot_init_stack_canary(); - cgroup_init_early(); local_irq_disable(); @@ -534,6 +528,11 @@ asmlinkage __visible void __init start_kernel(void) page_address_init(); pr_notice("%s", linux_banner); setup_arch(&command_line); + /* + * Set up the the initial canary and entropy after arch + */ + add_latent_entropy(); + boot_init_stack_canary(); mm_init_cpumask(&init_mm); setup_command_line(command_line); setup_nr_cpu_ids(); -- 2.13.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCHv2 1/2] init: Move stack canary initialization after setup_arch 2017-08-16 22:46 ` [PATCHv2 1/2] init: Move stack canary initialization after setup_arch Laura Abbott @ 2017-08-16 22:50 ` Kees Cook 0 siblings, 0 replies; 9+ messages in thread From: Kees Cook @ 2017-08-16 22:50 UTC (permalink / raw) To: Laura Abbott Cc: Laura Abbott, kernel-hardening@lists.openwall.com, LKML, Linux-MM, Andrew Morton, Daniel Micay On Wed, Aug 16, 2017 at 3:46 PM, Laura Abbott <labbott@redhat.com> wrote: > From: Laura Abbott <lauraa@codeaurora.org> > > Stack canary intialization involves getting a random number. > Getting this random number may involve accessing caches or other > architectural specific features which are not available until > after the architecture is setup. Move the stack canary initialization > later to accomodate this. > > Signed-off-by: Laura Abbott <lauraa@codeaurora.org> > Signed-off-by: Laura Abbott <labbott@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> -Kees > --- > v2: Also moved add_latent_entropy per suggestion of Kees. > --- > init/main.c | 11 +++++------ > 1 file changed, 5 insertions(+), 6 deletions(-) > > diff --git a/init/main.c b/init/main.c > index 052481fbe363..21d599eaad06 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -515,12 +515,6 @@ asmlinkage __visible void __init start_kernel(void) > smp_setup_processor_id(); > debug_objects_early_init(); > > - /* > - * Set up the initial canary ASAP: > - */ > - add_latent_entropy(); > - boot_init_stack_canary(); > - > cgroup_init_early(); > > local_irq_disable(); > @@ -534,6 +528,11 @@ asmlinkage __visible void __init start_kernel(void) > page_address_init(); > pr_notice("%s", linux_banner); > setup_arch(&command_line); > + /* > + * Set up the the initial canary and entropy after arch > + */ > + add_latent_entropy(); > + boot_init_stack_canary(); > mm_init_cpumask(&init_mm); > setup_command_line(command_line); > setup_nr_cpu_ids(); > -- > 2.13.0 > -- Kees Cook Pixel Security -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCHv2 2/2] extract early boot entropy from the passed cmdline 2017-08-16 22:46 [PATCHv2 0/2] Command line randomness Laura Abbott 2017-08-16 22:46 ` [PATCHv2 1/2] init: Move stack canary initialization after setup_arch Laura Abbott @ 2017-08-16 22:46 ` Laura Abbott 2017-08-16 22:48 ` Kees Cook 2017-08-17 4:56 ` [kernel-hardening] " Nick Kralevich 1 sibling, 2 replies; 9+ messages in thread From: Laura Abbott @ 2017-08-16 22:46 UTC (permalink / raw) To: Kees Cook Cc: Daniel Micay, kernel-hardening, linux-kernel, linux-mm, Andrew Morton, Laura Abbott From: Daniel Micay <danielmicay@gmail.com> Existing Android bootloaders usually pass data useful as early entropy 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). Signed-off-by: Daniel Micay <danielmicay@gmail.com> [labbott: Line-wrapped command line] Signed-off-by: Laura Abbott <labbott@redhat.com> --- init/main.c | 1 + 1 file changed, 1 insertion(+) diff --git a/init/main.c b/init/main.c index 21d599eaad06..cb051aec46ef 100644 --- a/init/main.c +++ b/init/main.c @@ -533,6 +533,7 @@ asmlinkage __visible void __init start_kernel(void) */ add_latent_entropy(); boot_init_stack_canary(); + add_device_randomness(command_line, strlen(command_line)); mm_init_cpumask(&init_mm); setup_command_line(command_line); setup_nr_cpu_ids(); -- 2.13.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCHv2 2/2] extract early boot entropy from the passed cmdline 2017-08-16 22:46 ` [PATCHv2 2/2] extract early boot entropy from the passed cmdline Laura Abbott @ 2017-08-16 22:48 ` Kees Cook 2017-08-16 22:53 ` Laura Abbott 2017-08-17 4:56 ` [kernel-hardening] " Nick Kralevich 1 sibling, 1 reply; 9+ messages in thread From: Kees Cook @ 2017-08-16 22:48 UTC (permalink / raw) To: Laura Abbott Cc: Daniel Micay, kernel-hardening@lists.openwall.com, LKML, Linux-MM, Andrew Morton On Wed, Aug 16, 2017 at 3:46 PM, Laura Abbott <labbott@redhat.com> wrote: > From: Daniel Micay <danielmicay@gmail.com> > > Existing Android bootloaders usually pass data useful as early entropy > 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). > > Signed-off-by: Daniel Micay <danielmicay@gmail.com> > [labbott: Line-wrapped command line] > Signed-off-by: Laura Abbott <labbott@redhat.com> > --- > init/main.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/init/main.c b/init/main.c > index 21d599eaad06..cb051aec46ef 100644 > --- a/init/main.c > +++ b/init/main.c > @@ -533,6 +533,7 @@ asmlinkage __visible void __init start_kernel(void) > */ > add_latent_entropy(); > boot_init_stack_canary(); > + add_device_randomness(command_line, strlen(command_line)); This should be above the add_latent_entropy() line there so the cmdline entropy can contribute to the canary entropy. -Kees > mm_init_cpumask(&init_mm); > setup_command_line(command_line); > setup_nr_cpu_ids(); > -- > 2.13.0 > -- Kees Cook Pixel Security -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCHv2 2/2] extract early boot entropy from the passed cmdline 2017-08-16 22:48 ` Kees Cook @ 2017-08-16 22:53 ` Laura Abbott 0 siblings, 0 replies; 9+ messages in thread From: Laura Abbott @ 2017-08-16 22:53 UTC (permalink / raw) To: Kees Cook Cc: Daniel Micay, kernel-hardening@lists.openwall.com, LKML, Linux-MM, Andrew Morton On 08/16/2017 03:48 PM, Kees Cook wrote: > On Wed, Aug 16, 2017 at 3:46 PM, Laura Abbott <labbott@redhat.com> wrote: >> From: Daniel Micay <danielmicay@gmail.com> >> >> Existing Android bootloaders usually pass data useful as early entropy >> 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). >> >> Signed-off-by: Daniel Micay <danielmicay@gmail.com> >> [labbott: Line-wrapped command line] >> Signed-off-by: Laura Abbott <labbott@redhat.com> >> --- >> init/main.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/init/main.c b/init/main.c >> index 21d599eaad06..cb051aec46ef 100644 >> --- a/init/main.c >> +++ b/init/main.c >> @@ -533,6 +533,7 @@ asmlinkage __visible void __init start_kernel(void) >> */ >> add_latent_entropy(); >> boot_init_stack_canary(); >> + add_device_randomness(command_line, strlen(command_line)); > > This should be above the add_latent_entropy() line there so the > cmdline entropy can contribute to the canary entropy. > Yeah, bad merge on my fault. Will spin a v3. > -Kees > >> mm_init_cpumask(&init_mm); >> setup_command_line(command_line); >> setup_nr_cpu_ids(); >> -- >> 2.13.0 >> > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [kernel-hardening] [PATCHv2 2/2] extract early boot entropy from the passed cmdline 2017-08-16 22:46 ` [PATCHv2 2/2] extract early boot entropy from the passed cmdline Laura Abbott 2017-08-16 22:48 ` Kees Cook @ 2017-08-17 4:56 ` Nick Kralevich 2017-08-17 4:58 ` Kees Cook 1 sibling, 1 reply; 9+ messages in thread From: Nick Kralevich @ 2017-08-17 4:56 UTC (permalink / raw) To: Laura Abbott Cc: Kees Cook, Daniel Micay, kernel-hardening, lkml, linux-mm, Andrew Morton On Wed, Aug 16, 2017 at 3:46 PM, Laura Abbott <labbott@redhat.com> wrote: > From: Daniel Micay <danielmicay@gmail.com> > > Existing Android bootloaders usually pass data useful as early entropy > on the kernel command-line. It may also be the case on other embedded > systems. Sample command-line from a Google Pixel running CopperheadOS: > Why is it better to put this into the kernel, rather than just rely on the existing userspace functionality which does exactly the same thing? This is what Android already does today: https://android-review.googlesource.com/198113 -- Nick -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [kernel-hardening] [PATCHv2 2/2] extract early boot entropy from the passed cmdline 2017-08-17 4:56 ` [kernel-hardening] " Nick Kralevich @ 2017-08-17 4:58 ` Kees Cook 2017-08-17 5:10 ` Daniel Micay 0 siblings, 1 reply; 9+ messages in thread From: Kees Cook @ 2017-08-17 4:58 UTC (permalink / raw) To: Nick Kralevich Cc: Laura Abbott, Daniel Micay, kernel-hardening@lists.openwall.com, lkml, Linux-MM, Andrew Morton On Wed, Aug 16, 2017 at 9:56 PM, Nick Kralevich <nnk@google.com> wrote: > On Wed, Aug 16, 2017 at 3:46 PM, Laura Abbott <labbott@redhat.com> wrote: >> From: Daniel Micay <danielmicay@gmail.com> >> >> Existing Android bootloaders usually pass data useful as early entropy >> on the kernel command-line. It may also be the case on other embedded >> systems. Sample command-line from a Google Pixel running CopperheadOS: >> > > Why is it better to put this into the kernel, rather than just rely on > the existing userspace functionality which does exactly the same > thing? This is what Android already does today: > https://android-review.googlesource.com/198113 That's too late for setting up the kernel stack canary, among other things. The kernel will also be generating some early secrets for slab cache canaries, etc. That all needs to happen well before init is started. -Kees -- Kees Cook Pixel Security -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [kernel-hardening] [PATCHv2 2/2] extract early boot entropy from the passed cmdline 2017-08-17 4:58 ` Kees Cook @ 2017-08-17 5:10 ` Daniel Micay 0 siblings, 0 replies; 9+ messages in thread From: Daniel Micay @ 2017-08-17 5:10 UTC (permalink / raw) To: Kees Cook, Nick Kralevich Cc: Laura Abbott, kernel-hardening@lists.openwall.com, lkml, Linux-MM, Andrew Morton On Wed, 2017-08-16 at 21:58 -0700, Kees Cook wrote: > On Wed, Aug 16, 2017 at 9:56 PM, Nick Kralevich <nnk@google.com> > wrote: > > On Wed, Aug 16, 2017 at 3:46 PM, Laura Abbott <labbott@redhat.com> > > wrote: > > > From: Daniel Micay <danielmicay@gmail.com> > > > > > > Existing Android bootloaders usually pass data useful as early > > > entropy > > > on the kernel command-line. It may also be the case on other > > > embedded > > > systems. Sample command-line from a Google Pixel running > > > CopperheadOS: > > > > > > > Why is it better to put this into the kernel, rather than just rely > > on > > the existing userspace functionality which does exactly the same > > thing? This is what Android already does today: > > https://android-review.googlesource.com/198113 > > That's too late for setting up the kernel stack canary, among other > things. The kernel will also be generating some early secrets for slab > cache canaries, etc. That all needs to happen well before init is > started. > > -Kees > It's also unfortunately the kernel's global stack canary for the entire boot since unlike x86 there aren't per-task canaries. GCC / Clang access it via a segment register on x86 vs. a global on other architectures. In theory it could be task-local elsewhere but doing it efficiently would imply reserving a register to store the random value. I think that may actually end up helping performance more than it hurts by not needing to read the global stack canary value from cache repeatedly. If stack canaries were augmented into something more (XOR in the retaddr and offer the option of more coverage than STRONG) it would be more important. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-08-17 5:10 UTC | newest] Thread overview: 9+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2017-08-16 22:46 [PATCHv2 0/2] Command line randomness Laura Abbott 2017-08-16 22:46 ` [PATCHv2 1/2] init: Move stack canary initialization after setup_arch Laura Abbott 2017-08-16 22:50 ` Kees Cook 2017-08-16 22:46 ` [PATCHv2 2/2] extract early boot entropy from the passed cmdline Laura Abbott 2017-08-16 22:48 ` Kees Cook 2017-08-16 22:53 ` Laura Abbott 2017-08-17 4:56 ` [kernel-hardening] " Nick Kralevich 2017-08-17 4:58 ` Kees Cook 2017-08-17 5:10 ` Daniel Micay
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).