| Message ID | 1517201477-12326-1-git-send-email-me@tobin.cc (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Tobin, On Mon, 2018-01-29 at 15:51 +1100, Tobin C. Harding wrote: > Currently script only supports x86_64 and ppc64. It would be nice to be > able to scan 32-bit machines also. We can add support for > 32-bit architectures by modifying how we check for false positives, > taking advantage of the page offset used by the kernel, and using the > correct regular expression. > > Support for 32-bit machines is enabled by the observation the kernel > addresses on 32-bit machines are larger than the page offset. We can > use this to filter false positives when scanning the kernel for leaking > addresses. > > Programmatic determination of the running architecture is not > immediately obvious. We therefore provide a flag to enable scanning of > 32-bit kernels. Also we can check the kernel config file for the offset > and if not found default to 0xc0000000. A command line option to parse > in the page offset is also provided. We do automatically detect > architecture if running on ix86. > > Add support for 32-bit kernels. Add a command line option for page > offset. > > Suggested-by: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com> > Signed-off-by: Tobin C. Harding <me@tobin.cc> > --- > > The basis for this patch has been in development for a while by Kaiwan > but didn't get finished before the merge window opened. I'd like to > fast track this and get it to Linus this merge window (considering > Spectre/Meltdown). I have finished this work off and added the > Suggested-by tag. Kaiwan I hope you are not upset by this, extra > ordinary circumstances seemed to require this action. Definitely not; I understand and am glad you're on it a 100%. Apologies that I couldn't work on this right now.. will try and keep track too. Thanks, Kaiwan. > > thanks, > Tobin. > > scripts/leaking_addresses.pl | 84 ++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 78 insertions(+), 6 deletions(-) > > diff --git a/scripts/leaking_addresses.pl b/scripts/leaking_addresses.pl > index 64a3cfa1175b..c13eb53d1c5a 100755 > --- a/scripts/leaking_addresses.pl > +++ b/scripts/leaking_addresses.pl > @@ -34,7 +34,7 @@ my $TIMEOUT = 10; > # Script can only grep for kernel addresses on the following architectures. If > # your architecture is not listed here and has a grep'able kernel address please > # consider submitting a patch. > -my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64'); > +my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64', 'x86'); > > # Command line options. > my $help = 0; > @@ -46,6 +46,8 @@ my $suppress_dmesg = 0; # Don't show dmesg in output. > my $squash_by_path = 0; # Summary report grouped by absolute path. > my $squash_by_filename = 0; # Summary report grouped by filename. > my $kernel_config_file = ""; # Kernel configuration file. > +my $opt_32bit = 0; # Scan 32-bit kernel. > +my $page_offset_32bit = 0; # Page offset for 32-bit kernel. > > # Do not parse these files (absolute path). > my @skip_parse_files_abs = ('/proc/kmsg', > @@ -103,6 +105,8 @@ Options: > --squash-by-path Show one result per unique path. > --squash-by-filename Show one result per unique filename. > --kernel-config-file=<file> Kernel configuration file (e.g /boot/config) > + --32-bit Scan 32-bit kernel. > + --page-offset-32-bit=o Page offset (for 32-bit kernel 0xABCD1234). > -d, --debug Display debugging output. > -h, --help, --versionq Display this help and exit. > > @@ -123,6 +127,8 @@ GetOptions( > 'squash-by-filename' => \$squash_by_filename, > 'raw' => \$raw, > 'kernel-config-file=s' => \$kernel_config_file, > + '32-bit' => \$opt_32bit, > + 'page-offset-32-bit=o' => \$page_offset_32bit, > ) or help(1); > > help(0) if ($help); > @@ -138,7 +144,7 @@ if (!$input_raw and ($squash_by_path or $squash_by_filename)) { > exit(128); > } > > -if (!is_supported_architecture()) { > +if (!(is_supported_architecture() or $opt_32bit or $page_offset_32bit)) { > printf "\nScript does not support your architecture, sorry.\n"; > printf "\nCurrently we support: \n\n"; > foreach(@SUPPORTED_ARCHITECTURES) { > @@ -146,6 +152,9 @@ if (!is_supported_architecture()) { > } > printf("\n"); > > + printf("If you are running a 32-bit architecture you may use:\n"); > + printf("\n\t--32-bit or --page-offset-32-bit=<page offset>\n\n"); > + > my $archname = `uname -m`; > printf("Machine hardware name (`uname -m`): %s\n", $archname); > > @@ -169,7 +178,28 @@ sub dprint > > sub is_supported_architecture > { > - return (is_x86_64() or is_ppc64()); > + return (is_x86_64() or is_ppc64() or is_ix86_32()); > +} > + > +sub is_32bit > +{ > + # Allow --32-bit or --page-offset-32-bit to override > + if ($opt_32bit or $page_offset_32bit) { > + return 1; > + } > + > + return is_ix86_32(); > +} > + > +sub is_ix86_32 > +{ > + my $arch = `uname -m`; > + > + chomp $arch; > + if ($arch =~ m/i[3456]86/) { > + return 1; > + } > + return 0; > } > > sub is_arch > @@ -261,6 +291,12 @@ sub is_false_positive > { > my ($match) = @_; > > + if (is_32bit()) { > + return is_false_positive_32bit($match); > + } > + > + # 64 bit false positives. > + > if ($match =~ '\b(0x)?(f|F){16}\b' or > $match =~ '\b(0x)?0{16}\b') { > return 1; > @@ -273,6 +309,40 @@ sub is_false_positive > return 0; > } > > +sub is_false_positive_32bit > +{ > + my ($match) = @_; > + state $page_offset = get_page_offset(); > + > + if ($match =~ '\b(0x)?(f|F){8}\b') { > + return 1; > + } > + > + if (hex($match) < $page_offset) { > + return 1; > + } > + > + return 0; > +} > + > +# returns integer value > +sub get_page_offset > +{ > + my $page_offset; > + my $default_offset = 0xc0000000; > + > + # Allow --page-offset-32bit to override. > + if ($page_offset_32bit != 0) { > + return $page_offset_32bit; > + } > + > + $page_offset = get_kernel_config_option('CONFIG_PAGE_OFFSET'); > + if (!$page_offset) { > + return $default_offset; > + } > + return $page_offset; > +} > + > sub is_in_vsyscall_memory_region > { > my ($match) = @_; > @@ -314,11 +384,13 @@ sub may_leak_address > > sub get_address_re > { > - if (is_x86_64()) { > - return get_x86_64_re(); > - } elsif (is_ppc64()) { > + if (is_ppc64()) { > return '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b'; > + } elsif (is_32bit()) { > + return '\b(0x)?[[:xdigit:]]{8}\b'; > } > + > + return get_x86_64_re(); > } > > sub get_x86_64_re
On Tue, Jan 30, 2018 at 09:14:49AM +0530, kaiwan.billimoria@gmail.com wrote: > Hi Tobin, > > On Mon, 2018-01-29 at 15:51 +1100, Tobin C. Harding wrote: > > Currently script only supports x86_64 and ppc64. It would be nice to be > > able to scan 32-bit machines also. We can add support for > > 32-bit architectures by modifying how we check for false positives, > > taking advantage of the page offset used by the kernel, and using the > > correct regular expression. > > > > Support for 32-bit machines is enabled by the observation the kernel > > addresses on 32-bit machines are larger than the page offset. We can > > use this to filter false positives when scanning the kernel for leaking > > addresses. > > > > Programmatic determination of the running architecture is not > > immediately obvious. We therefore provide a flag to enable scanning of > > 32-bit kernels. Also we can check the kernel config file for the offset > > and if not found default to 0xc0000000. A command line option to parse > > in the page offset is also provided. We do automatically detect > > architecture if running on ix86. > > > > Add support for 32-bit kernels. Add a command line option for page > > offset. > > > > Suggested-by: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com> > > Signed-off-by: Tobin C. Harding <me@tobin.cc> > > --- > > > > The basis for this patch has been in development for a while by Kaiwan > > but didn't get finished before the merge window opened. I'd like to > > fast track this and get it to Linus this merge window (considering > > Spectre/Meltdown). I have finished this work off and added the > > Suggested-by tag. Kaiwan I hope you are not upset by this, extra > > ordinary circumstances seemed to require this action. > Definitely not; I understand and am glad you're on it a 100%. Apologies > that I couldn't work on this right now.. will try and keep track too. Thanks for the response. Tobin
diff --git a/scripts/leaking_addresses.pl b/scripts/leaking_addresses.pl index 64a3cfa1175b..c13eb53d1c5a 100755 --- a/scripts/leaking_addresses.pl +++ b/scripts/leaking_addresses.pl @@ -34,7 +34,7 @@ my $TIMEOUT = 10; # Script can only grep for kernel addresses on the following architectures. If # your architecture is not listed here and has a grep'able kernel address please # consider submitting a patch. -my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64'); +my @SUPPORTED_ARCHITECTURES = ('x86_64', 'ppc64', 'x86'); # Command line options. my $help = 0; @@ -46,6 +46,8 @@ my $suppress_dmesg = 0; # Don't show dmesg in output. my $squash_by_path = 0; # Summary report grouped by absolute path. my $squash_by_filename = 0; # Summary report grouped by filename. my $kernel_config_file = ""; # Kernel configuration file. +my $opt_32bit = 0; # Scan 32-bit kernel. +my $page_offset_32bit = 0; # Page offset for 32-bit kernel. # Do not parse these files (absolute path). my @skip_parse_files_abs = ('/proc/kmsg', @@ -103,6 +105,8 @@ Options: --squash-by-path Show one result per unique path. --squash-by-filename Show one result per unique filename. --kernel-config-file=<file> Kernel configuration file (e.g /boot/config) + --32-bit Scan 32-bit kernel. + --page-offset-32-bit=o Page offset (for 32-bit kernel 0xABCD1234). -d, --debug Display debugging output. -h, --help, --versionq Display this help and exit. @@ -123,6 +127,8 @@ GetOptions( 'squash-by-filename' => \$squash_by_filename, 'raw' => \$raw, 'kernel-config-file=s' => \$kernel_config_file, + '32-bit' => \$opt_32bit, + 'page-offset-32-bit=o' => \$page_offset_32bit, ) or help(1); help(0) if ($help); @@ -138,7 +144,7 @@ if (!$input_raw and ($squash_by_path or $squash_by_filename)) { exit(128); } -if (!is_supported_architecture()) { +if (!(is_supported_architecture() or $opt_32bit or $page_offset_32bit)) { printf "\nScript does not support your architecture, sorry.\n"; printf "\nCurrently we support: \n\n"; foreach(@SUPPORTED_ARCHITECTURES) { @@ -146,6 +152,9 @@ if (!is_supported_architecture()) { } printf("\n"); + printf("If you are running a 32-bit architecture you may use:\n"); + printf("\n\t--32-bit or --page-offset-32-bit=<page offset>\n\n"); + my $archname = `uname -m`; printf("Machine hardware name (`uname -m`): %s\n", $archname); @@ -169,7 +178,28 @@ sub dprint sub is_supported_architecture { - return (is_x86_64() or is_ppc64()); + return (is_x86_64() or is_ppc64() or is_ix86_32()); +} + +sub is_32bit +{ + # Allow --32-bit or --page-offset-32-bit to override + if ($opt_32bit or $page_offset_32bit) { + return 1; + } + + return is_ix86_32(); +} + +sub is_ix86_32 +{ + my $arch = `uname -m`; + + chomp $arch; + if ($arch =~ m/i[3456]86/) { + return 1; + } + return 0; } sub is_arch @@ -261,6 +291,12 @@ sub is_false_positive { my ($match) = @_; + if (is_32bit()) { + return is_false_positive_32bit($match); + } + + # 64 bit false positives. + if ($match =~ '\b(0x)?(f|F){16}\b' or $match =~ '\b(0x)?0{16}\b') { return 1; @@ -273,6 +309,40 @@ sub is_false_positive return 0; } +sub is_false_positive_32bit +{ + my ($match) = @_; + state $page_offset = get_page_offset(); + + if ($match =~ '\b(0x)?(f|F){8}\b') { + return 1; + } + + if (hex($match) < $page_offset) { + return 1; + } + + return 0; +} + +# returns integer value +sub get_page_offset +{ + my $page_offset; + my $default_offset = 0xc0000000; + + # Allow --page-offset-32bit to override. + if ($page_offset_32bit != 0) { + return $page_offset_32bit; + } + + $page_offset = get_kernel_config_option('CONFIG_PAGE_OFFSET'); + if (!$page_offset) { + return $default_offset; + } + return $page_offset; +} + sub is_in_vsyscall_memory_region { my ($match) = @_; @@ -314,11 +384,13 @@ sub may_leak_address sub get_address_re { - if (is_x86_64()) { - return get_x86_64_re(); - } elsif (is_ppc64()) { + if (is_ppc64()) { return '\b(0x)?[89abcdef]00[[:xdigit:]]{13}\b'; + } elsif (is_32bit()) { + return '\b(0x)?[[:xdigit:]]{8}\b'; } + + return get_x86_64_re(); } sub get_x86_64_re
Currently script only supports x86_64 and ppc64. It would be nice to be able to scan 32-bit machines also. We can add support for 32-bit architectures by modifying how we check for false positives, taking advantage of the page offset used by the kernel, and using the correct regular expression. Support for 32-bit machines is enabled by the observation the kernel addresses on 32-bit machines are larger than the page offset. We can use this to filter false positives when scanning the kernel for leaking addresses. Programmatic determination of the running architecture is not immediately obvious. We therefore provide a flag to enable scanning of 32-bit kernels. Also we can check the kernel config file for the offset and if not found default to 0xc0000000. A command line option to parse in the page offset is also provided. We do automatically detect architecture if running on ix86. Add support for 32-bit kernels. Add a command line option for page offset. Suggested-by: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com> Signed-off-by: Tobin C. Harding <me@tobin.cc> --- The basis for this patch has been in development for a while by Kaiwan but didn't get finished before the merge window opened. I'd like to fast track this and get it to Linus this merge window (considering Spectre/Meltdown). I have finished this work off and added the Suggested-by tag. Kaiwan I hope you are not upset by this, extra ordinary circumstances seemed to require this action. thanks, Tobin. scripts/leaking_addresses.pl | 84 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 78 insertions(+), 6 deletions(-)