| Message ID | 20191004075050.73327-4-ruscur@russell.cc (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Implement STRICT_MODULE_RWX for powerpc | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (6edfc6487b474fe01857dc3f1a9cd701bb9b21c8) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 48 lines checked |
Russell Currey <ruscur@russell.cc> writes: > Very rudimentary, just > > echo 1 > [debugfs]/check_wx_pages > > and check the kernel log. Useful for testing strict module RWX. I was very confused that this requires the boot-time testing to be enabled to appear in debugfs. Could you change the kconfig snippet for PPC_DEBUG_WX to mention the runtime testing? Kind regards, Daniel > > Also fixed a typo. > > Signed-off-by: Russell Currey <ruscur@russell.cc> > --- > arch/powerpc/mm/ptdump/ptdump.c | 31 +++++++++++++++++++++++++------ > 1 file changed, 25 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c > index 2f9ddc29c535..0547cd9f264e 100644 > --- a/arch/powerpc/mm/ptdump/ptdump.c > +++ b/arch/powerpc/mm/ptdump/ptdump.c > @@ -4,7 +4,7 @@ > * > * This traverses the kernel pagetables and dumps the > * information about the used sections of memory to > - * /sys/kernel/debug/kernel_pagetables. > + * /sys/kernel/debug/kernel_page_tables. > * > * Derived from the arm64 implementation: > * Copyright (c) 2014, The Linux Foundation, Laura Abbott. > @@ -409,16 +409,35 @@ void ptdump_check_wx(void) > else > pr_info("Checked W+X mappings: passed, no W+X pages found\n"); > } > + > +static int check_wx_debugfs_set(void *data, u64 val) > +{ > + if (val != 1ULL) > + return -EINVAL; > + > + ptdump_check_wx(); > + > + return 0; > +} > + > +DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n"); > #endif > > static int ptdump_init(void) > { > - struct dentry *debugfs_file; > - > populate_markers(); > build_pgtable_complete_mask(); > - debugfs_file = debugfs_create_file("kernel_page_tables", 0400, NULL, > - NULL, &ptdump_fops); > - return debugfs_file ? 0 : -ENOMEM; > + > + if (!debugfs_create_file("kernel_page_tables", 0400, NULL, > + NULL, &ptdump_fops)) > + return -ENOMEM; > + > +#ifdef CONFIG_PPC_DEBUG_WX > + if (!debugfs_create_file("check_wx_pages", 0200, NULL, > + NULL, &check_wx_fops)) > + return -ENOMEM; > +#endif > + > + return 0; > } > device_initcall(ptdump_init); > -- > 2.23.0
Le 04/10/2019 à 09:50, Russell Currey a écrit : > Very rudimentary, just > > echo 1 > [debugfs]/check_wx_pages > > and check the kernel log. Useful for testing strict module RWX. > > Also fixed a typo. > > Signed-off-by: Russell Currey <ruscur@russell.cc> > --- > arch/powerpc/mm/ptdump/ptdump.c | 31 +++++++++++++++++++++++++------ > 1 file changed, 25 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c > index 2f9ddc29c535..0547cd9f264e 100644 > --- a/arch/powerpc/mm/ptdump/ptdump.c > +++ b/arch/powerpc/mm/ptdump/ptdump.c > @@ -4,7 +4,7 @@ > * > * This traverses the kernel pagetables and dumps the > * information about the used sections of memory to > - * /sys/kernel/debug/kernel_pagetables. > + * /sys/kernel/debug/kernel_page_tables. > * > * Derived from the arm64 implementation: > * Copyright (c) 2014, The Linux Foundation, Laura Abbott. > @@ -409,16 +409,35 @@ void ptdump_check_wx(void) > else > pr_info("Checked W+X mappings: passed, no W+X pages found\n"); > } > + > +static int check_wx_debugfs_set(void *data, u64 val) > +{ > + if (val != 1ULL) > + return -EINVAL; > + > + ptdump_check_wx(); > + > + return 0; > +} > + > +DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n"); > #endif > > static int ptdump_init(void) > { > - struct dentry *debugfs_file; > - > populate_markers(); > build_pgtable_complete_mask(); > - debugfs_file = debugfs_create_file("kernel_page_tables", 0400, NULL, > - NULL, &ptdump_fops); > - return debugfs_file ? 0 : -ENOMEM; > + > + if (!debugfs_create_file("kernel_page_tables", 0400, NULL, > + NULL, &ptdump_fops)) > + return -ENOMEM; > + > +#ifdef CONFIG_PPC_DEBUG_WX > + if (!debugfs_create_file("check_wx_pages", 0200, NULL, > + NULL, &check_wx_fops)) > + return -ENOMEM; > +#endif The above seems to be completely independant from everything else in ptdump_init(). Could we avoid this #ifdef block inside ptdump_init() by creating a selfstanding device_initcall() for that through a function called ptdump_check_wx_init() defined inside the same #ifdef block as ptdump_check_wx() ? Christophe > + > + return 0; > } > device_initcall(ptdump_init); >
On Tue, 2019-10-08 at 08:21 +0200, Christophe Leroy wrote: > > Le 04/10/2019 à 09:50, Russell Currey a écrit : > > Very rudimentary, just > > > > echo 1 > [debugfs]/check_wx_pages > > > > and check the kernel log. Useful for testing strict module RWX. > > > > Also fixed a typo. > > > > Signed-off-by: Russell Currey <ruscur@russell.cc> > > --- > > arch/powerpc/mm/ptdump/ptdump.c | 31 +++++++++++++++++++++++++--- > > --- > > 1 file changed, 25 insertions(+), 6 deletions(-) > > > > diff --git a/arch/powerpc/mm/ptdump/ptdump.c > > b/arch/powerpc/mm/ptdump/ptdump.c > > index 2f9ddc29c535..0547cd9f264e 100644 > > --- a/arch/powerpc/mm/ptdump/ptdump.c > > +++ b/arch/powerpc/mm/ptdump/ptdump.c > > @@ -4,7 +4,7 @@ > > * > > * This traverses the kernel pagetables and dumps the > > * information about the used sections of memory to > > - * /sys/kernel/debug/kernel_pagetables. > > + * /sys/kernel/debug/kernel_page_tables. > > * > > * Derived from the arm64 implementation: > > * Copyright (c) 2014, The Linux Foundation, Laura Abbott. > > @@ -409,16 +409,35 @@ void ptdump_check_wx(void) > > else > > pr_info("Checked W+X mappings: passed, no W+X pages > > found\n"); > > } > > + > > +static int check_wx_debugfs_set(void *data, u64 val) > > +{ > > + if (val != 1ULL) > > + return -EINVAL; > > + > > + ptdump_check_wx(); > > + > > + return 0; > > +} > > + > > +DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, > > "%llu\n"); > > #endif > > > > static int ptdump_init(void) > > { > > - struct dentry *debugfs_file; > > - > > populate_markers(); > > build_pgtable_complete_mask(); > > - debugfs_file = debugfs_create_file("kernel_page_tables", 0400, > > NULL, > > - NULL, &ptdump_fops); > > - return debugfs_file ? 0 : -ENOMEM; > > + > > + if (!debugfs_create_file("kernel_page_tables", 0400, NULL, > > + NULL, &ptdump_fops)) > > + return -ENOMEM; > > + > > +#ifdef CONFIG_PPC_DEBUG_WX > > + if (!debugfs_create_file("check_wx_pages", 0200, NULL, > > + NULL, &check_wx_fops)) > > + return -ENOMEM; > > +#endif > > The above seems to be completely independant from everything else in > ptdump_init(). > > Could we avoid this #ifdef block inside ptdump_init() by creating a > selfstanding device_initcall() for that through a function called > ptdump_check_wx_init() defined inside the same #ifdef block as > ptdump_check_wx() ? Yes that would be nicer, thanks > > Christophe > > > + > > + return 0; > > } > > device_initcall(ptdump_init); > >
diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c index 2f9ddc29c535..0547cd9f264e 100644 --- a/arch/powerpc/mm/ptdump/ptdump.c +++ b/arch/powerpc/mm/ptdump/ptdump.c @@ -4,7 +4,7 @@ * * This traverses the kernel pagetables and dumps the * information about the used sections of memory to - * /sys/kernel/debug/kernel_pagetables. + * /sys/kernel/debug/kernel_page_tables. * * Derived from the arm64 implementation: * Copyright (c) 2014, The Linux Foundation, Laura Abbott. @@ -409,16 +409,35 @@ void ptdump_check_wx(void) else pr_info("Checked W+X mappings: passed, no W+X pages found\n"); } + +static int check_wx_debugfs_set(void *data, u64 val) +{ + if (val != 1ULL) + return -EINVAL; + + ptdump_check_wx(); + + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n"); #endif static int ptdump_init(void) { - struct dentry *debugfs_file; - populate_markers(); build_pgtable_complete_mask(); - debugfs_file = debugfs_create_file("kernel_page_tables", 0400, NULL, - NULL, &ptdump_fops); - return debugfs_file ? 0 : -ENOMEM; + + if (!debugfs_create_file("kernel_page_tables", 0400, NULL, + NULL, &ptdump_fops)) + return -ENOMEM; + +#ifdef CONFIG_PPC_DEBUG_WX + if (!debugfs_create_file("check_wx_pages", 0200, NULL, + NULL, &check_wx_fops)) + return -ENOMEM; +#endif + + return 0; } device_initcall(ptdump_init);
Very rudimentary, just echo 1 > [debugfs]/check_wx_pages and check the kernel log. Useful for testing strict module RWX. Also fixed a typo. Signed-off-by: Russell Currey <ruscur@russell.cc> --- arch/powerpc/mm/ptdump/ptdump.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-)