| Message ID | 20220222141303.1392190-7-atomlin@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | module: core code clean up | expand |
Le 22/02/2022 à 15:12, Aaron Tomlin a écrit : > No functional change. > > This patch migrates code that makes module text > and rodata memory read-only and non-text memory > non-executable from core module code into > kernel/module/strict_rwx.c. > > Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> > --- > kernel/module/Makefile | 1 + > kernel/module/internal.h | 32 ++++++++++++ > kernel/module/main.c | 99 +------------------------------------- > kernel/module/strict_rwx.c | 85 ++++++++++++++++++++++++++++++++ > 4 files changed, 120 insertions(+), 97 deletions(-) > create mode 100644 kernel/module/strict_rwx.c > > diff --git a/kernel/module/Makefile b/kernel/module/Makefile > index 88774e386276..d313c8472cb3 100644 > --- a/kernel/module/Makefile > +++ b/kernel/module/Makefile > @@ -12,3 +12,4 @@ obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o > obj-$(CONFIG_MODULE_SIG) += signing.o > obj-$(CONFIG_LIVEPATCH) += livepatch.o > obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o > +obj-$(CONFIG_STRICT_MODULE_RWX) += strict_rwx.o > diff --git a/kernel/module/internal.h b/kernel/module/internal.h > index f1682e3677be..a6895bb5598a 100644 > --- a/kernel/module/internal.h > +++ b/kernel/module/internal.h > @@ -20,6 +20,17 @@ > /* Maximum number of characters written by module_flags() */ > #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) > > +/* > + * Modules' sections will be aligned on page boundaries > + * to ensure complete separation of code and data, but > + * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y > + */ > +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX > +# define debug_align(X) PAGE_ALIGN(X) > +#else > +# define debug_align(X) (X) > +#endif > + > extern struct mutex module_mutex; > extern struct list_head modules; > > @@ -126,3 +137,24 @@ static inline struct module *mod_find(unsigned long addr) > return NULL; > } > #endif /* CONFIG_MODULES_TREE_LOOKUP */ > + > +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX > +void frob_text(const struct module_layout *layout, int (*set_memory)(unsigned long start, > + int num_pages)); > +#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ > + > +#ifdef CONFIG_STRICT_MODULE_RWX > +void module_enable_ro(const struct module *mod, bool after_init); > +void module_enable_nx(const struct module *mod); > +int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, > + char *secstrings, struct module *mod); > + > +#else /* !CONFIG_STRICT_MODULE_RWX */ > +static inline void module_enable_nx(const struct module *mod) { } > +static inline void module_enable_ro(const struct module *mod, bool after_init) {} > +static inline int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, > + char *secstrings, struct module *mod) > +{ > + return 0; > +} > +#endif /* CONFIG_STRICT_MODULE_RWX */ > diff --git a/kernel/module/main.c b/kernel/module/main.c > index 76b53880ad91..5cd63f14b1ef 100644 > --- a/kernel/module/main.c > +++ b/kernel/module/main.c > @@ -63,17 +63,6 @@ > #define CREATE_TRACE_POINTS > #include <trace/events/module.h> > > -/* > - * Modules' sections will be aligned on page boundaries > - * to ensure complete separation of code and data, but > - * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y > - */ > -#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX > -# define debug_align(X) ALIGN(X, PAGE_SIZE) > -#else > -# define debug_align(X) (X) > -#endif > - > /* > * Mutex protects: > * 1) List of modules (also safely readable with preempt_disable), > @@ -1819,8 +1808,8 @@ static void mod_sysfs_teardown(struct module *mod) > * whether we are strict. > */ > #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX > -static void frob_text(const struct module_layout *layout, > - int (*set_memory)(unsigned long start, int num_pages)) > +void frob_text(const struct module_layout *layout, > + int (*set_memory)(unsigned long start, int num_pages)) > { > BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); > BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); > @@ -1837,90 +1826,6 @@ static void module_enable_x(const struct module *mod) > static void module_enable_x(const struct module *mod) { } > #endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ > > -#ifdef CONFIG_STRICT_MODULE_RWX > -static void frob_rodata(const struct module_layout *layout, > - int (*set_memory)(unsigned long start, int num_pages)) > -{ > - BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); > - BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); > - BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1)); > - set_memory((unsigned long)layout->base + layout->text_size, > - (layout->ro_size - layout->text_size) >> PAGE_SHIFT); > -} > - > -static void frob_ro_after_init(const struct module_layout *layout, > - int (*set_memory)(unsigned long start, int num_pages)) > -{ > - BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); > - BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1)); > - BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1)); > - set_memory((unsigned long)layout->base + layout->ro_size, > - (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT); > -} > - > -static void frob_writable_data(const struct module_layout *layout, > - int (*set_memory)(unsigned long start, int num_pages)) > -{ > - BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); > - BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1)); > - BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1)); > - set_memory((unsigned long)layout->base + layout->ro_after_init_size, > - (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT); > -} > - > -static void module_enable_ro(const struct module *mod, bool after_init) > -{ > - if (!rodata_enabled) > - return; > - > - set_vm_flush_reset_perms(mod->core_layout.base); > - set_vm_flush_reset_perms(mod->init_layout.base); > - frob_text(&mod->core_layout, set_memory_ro); > - > - frob_rodata(&mod->core_layout, set_memory_ro); > - frob_text(&mod->init_layout, set_memory_ro); > - frob_rodata(&mod->init_layout, set_memory_ro); > - > - if (after_init) > - frob_ro_after_init(&mod->core_layout, set_memory_ro); > -} > - > -static void module_enable_nx(const struct module *mod) > -{ > - frob_rodata(&mod->core_layout, set_memory_nx); > - frob_ro_after_init(&mod->core_layout, set_memory_nx); > - frob_writable_data(&mod->core_layout, set_memory_nx); > - frob_rodata(&mod->init_layout, set_memory_nx); > - frob_writable_data(&mod->init_layout, set_memory_nx); > -} > - > -static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, > - char *secstrings, struct module *mod) > -{ > - const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR; > - int i; > - > - for (i = 0; i < hdr->e_shnum; i++) { > - if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) { > - pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n", > - mod->name, secstrings + sechdrs[i].sh_name, i); > - return -ENOEXEC; > - } > - } > - > - return 0; > -} > - > -#else /* !CONFIG_STRICT_MODULE_RWX */ > -static void module_enable_nx(const struct module *mod) { } > -static void module_enable_ro(const struct module *mod, bool after_init) {} > -static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, > - char *secstrings, struct module *mod) > -{ > - return 0; > -} > -#endif /* CONFIG_STRICT_MODULE_RWX */ > - > void __weak module_memfree(void *module_region) > { > /* > diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c > new file mode 100644 > index 000000000000..7949dfd449c2 > --- /dev/null > +++ b/kernel/module/strict_rwx.c > @@ -0,0 +1,85 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Module strict rwx > + * > + * Copyright (C) 2015 Rusty Russell > + */ > + > +#include <linux/module.h> > +#include <linux/mm.h> > +#include <linux/vmalloc.h> > +#include <linux/set_memory.h> > +#include "internal.h" > + > +static void frob_rodata(const struct module_layout *layout, > + int (*set_memory)(unsigned long start, int num_pages)) > +{ > + BUG_ON(!PAGE_ALIGNED(layout->base)); > + BUG_ON(!PAGE_ALIGNED(layout->text_size)); > + BUG_ON(!PAGE_ALIGNED(layout->ro_size)); > + set_memory((unsigned long)layout->base + layout->text_size, > + (layout->ro_size - layout->text_size) >> PAGE_SHIFT); > +} > + > +static void frob_ro_after_init(const struct module_layout *layout, > + int (*set_memory)(unsigned long start, int num_pages)) > +{ > + BUG_ON(!PAGE_ALIGNED(layout->base)); > + BUG_ON(!PAGE_ALIGNED(layout->ro_size)); > + BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size)); > + set_memory((unsigned long)layout->base + layout->ro_size, > + (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT); > +} > + > +static void frob_writable_data(const struct module_layout *layout, > + int (*set_memory)(unsigned long start, int num_pages)) > +{ > + BUG_ON(!PAGE_ALIGNED(layout->base)); > + BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size)); > + BUG_ON(!PAGE_ALIGNED(layout->size)); > + set_memory((unsigned long)layout->base + layout->ro_after_init_size, > + (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT); > +} > + > +void module_enable_ro(const struct module *mod, bool after_init) > +{ > + if (!rodata_enabled) > + return; > + > + set_vm_flush_reset_perms(mod->core_layout.base); > + set_vm_flush_reset_perms(mod->init_layout.base); > + frob_text(&mod->core_layout, set_memory_ro); > + > + frob_rodata(&mod->core_layout, set_memory_ro); > + frob_text(&mod->init_layout, set_memory_ro); > + frob_rodata(&mod->init_layout, set_memory_ro); > + > + if (after_init) > + frob_ro_after_init(&mod->core_layout, set_memory_ro); > +} > + > +void module_enable_nx(const struct module *mod) > +{ > + frob_rodata(&mod->core_layout, set_memory_nx); > + frob_ro_after_init(&mod->core_layout, set_memory_nx); > + frob_writable_data(&mod->core_layout, set_memory_nx); > + frob_rodata(&mod->init_layout, set_memory_nx); > + frob_writable_data(&mod->init_layout, set_memory_nx); > +} > + > +int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, > + char *secstrings, struct module *mod) > +{ > + const unsigned long shf_wx = SHF_WRITE | SHF_EXECINSTR; > + int i; > + > + for (i = 0; i < hdr->e_shnum; i++) { > + if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) { > + pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n", > + mod->name, secstrings + sechdrs[i].sh_name, i); > + return -ENOEXEC; > + } > + } > + > + return 0; > +}
diff --git a/kernel/module/Makefile b/kernel/module/Makefile index 88774e386276..d313c8472cb3 100644 --- a/kernel/module/Makefile +++ b/kernel/module/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_MODULE_DECOMPRESS) += decompress.o obj-$(CONFIG_MODULE_SIG) += signing.o obj-$(CONFIG_LIVEPATCH) += livepatch.o obj-$(CONFIG_MODULES_TREE_LOOKUP) += tree_lookup.o +obj-$(CONFIG_STRICT_MODULE_RWX) += strict_rwx.o diff --git a/kernel/module/internal.h b/kernel/module/internal.h index f1682e3677be..a6895bb5598a 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -20,6 +20,17 @@ /* Maximum number of characters written by module_flags() */ #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) +/* + * Modules' sections will be aligned on page boundaries + * to ensure complete separation of code and data, but + * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y + */ +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX +# define debug_align(X) PAGE_ALIGN(X) +#else +# define debug_align(X) (X) +#endif + extern struct mutex module_mutex; extern struct list_head modules; @@ -126,3 +137,24 @@ static inline struct module *mod_find(unsigned long addr) return NULL; } #endif /* CONFIG_MODULES_TREE_LOOKUP */ + +#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX +void frob_text(const struct module_layout *layout, int (*set_memory)(unsigned long start, + int num_pages)); +#endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ + +#ifdef CONFIG_STRICT_MODULE_RWX +void module_enable_ro(const struct module *mod, bool after_init); +void module_enable_nx(const struct module *mod); +int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, + char *secstrings, struct module *mod); + +#else /* !CONFIG_STRICT_MODULE_RWX */ +static inline void module_enable_nx(const struct module *mod) { } +static inline void module_enable_ro(const struct module *mod, bool after_init) {} +static inline int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, + char *secstrings, struct module *mod) +{ + return 0; +} +#endif /* CONFIG_STRICT_MODULE_RWX */ diff --git a/kernel/module/main.c b/kernel/module/main.c index 76b53880ad91..5cd63f14b1ef 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -63,17 +63,6 @@ #define CREATE_TRACE_POINTS #include <trace/events/module.h> -/* - * Modules' sections will be aligned on page boundaries - * to ensure complete separation of code and data, but - * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y - */ -#ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX -# define debug_align(X) ALIGN(X, PAGE_SIZE) -#else -# define debug_align(X) (X) -#endif - /* * Mutex protects: * 1) List of modules (also safely readable with preempt_disable), @@ -1819,8 +1808,8 @@ static void mod_sysfs_teardown(struct module *mod) * whether we are strict. */ #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX -static void frob_text(const struct module_layout *layout, - int (*set_memory)(unsigned long start, int num_pages)) +void frob_text(const struct module_layout *layout, + int (*set_memory)(unsigned long start, int num_pages)) { BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); @@ -1837,90 +1826,6 @@ static void module_enable_x(const struct module *mod) static void module_enable_x(const struct module *mod) { } #endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ -#ifdef CONFIG_STRICT_MODULE_RWX -static void frob_rodata(const struct module_layout *layout, - int (*set_memory)(unsigned long start, int num_pages)) -{ - BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); - BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); - BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1)); - set_memory((unsigned long)layout->base + layout->text_size, - (layout->ro_size - layout->text_size) >> PAGE_SHIFT); -} - -static void frob_ro_after_init(const struct module_layout *layout, - int (*set_memory)(unsigned long start, int num_pages)) -{ - BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); - BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1)); - BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1)); - set_memory((unsigned long)layout->base + layout->ro_size, - (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT); -} - -static void frob_writable_data(const struct module_layout *layout, - int (*set_memory)(unsigned long start, int num_pages)) -{ - BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); - BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1)); - BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1)); - set_memory((unsigned long)layout->base + layout->ro_after_init_size, - (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT); -} - -static void module_enable_ro(const struct module *mod, bool after_init) -{ - if (!rodata_enabled) - return; - - set_vm_flush_reset_perms(mod->core_layout.base); - set_vm_flush_reset_perms(mod->init_layout.base); - frob_text(&mod->core_layout, set_memory_ro); - - frob_rodata(&mod->core_layout, set_memory_ro); - frob_text(&mod->init_layout, set_memory_ro); - frob_rodata(&mod->init_layout, set_memory_ro); - - if (after_init) - frob_ro_after_init(&mod->core_layout, set_memory_ro); -} - -static void module_enable_nx(const struct module *mod) -{ - frob_rodata(&mod->core_layout, set_memory_nx); - frob_ro_after_init(&mod->core_layout, set_memory_nx); - frob_writable_data(&mod->core_layout, set_memory_nx); - frob_rodata(&mod->init_layout, set_memory_nx); - frob_writable_data(&mod->init_layout, set_memory_nx); -} - -static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, - char *secstrings, struct module *mod) -{ - const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR; - int i; - - for (i = 0; i < hdr->e_shnum; i++) { - if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) { - pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n", - mod->name, secstrings + sechdrs[i].sh_name, i); - return -ENOEXEC; - } - } - - return 0; -} - -#else /* !CONFIG_STRICT_MODULE_RWX */ -static void module_enable_nx(const struct module *mod) { } -static void module_enable_ro(const struct module *mod, bool after_init) {} -static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, - char *secstrings, struct module *mod) -{ - return 0; -} -#endif /* CONFIG_STRICT_MODULE_RWX */ - void __weak module_memfree(void *module_region) { /* diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c new file mode 100644 index 000000000000..7949dfd449c2 --- /dev/null +++ b/kernel/module/strict_rwx.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Module strict rwx + * + * Copyright (C) 2015 Rusty Russell + */ + +#include <linux/module.h> +#include <linux/mm.h> +#include <linux/vmalloc.h> +#include <linux/set_memory.h> +#include "internal.h" + +static void frob_rodata(const struct module_layout *layout, + int (*set_memory)(unsigned long start, int num_pages)) +{ + BUG_ON(!PAGE_ALIGNED(layout->base)); + BUG_ON(!PAGE_ALIGNED(layout->text_size)); + BUG_ON(!PAGE_ALIGNED(layout->ro_size)); + set_memory((unsigned long)layout->base + layout->text_size, + (layout->ro_size - layout->text_size) >> PAGE_SHIFT); +} + +static void frob_ro_after_init(const struct module_layout *layout, + int (*set_memory)(unsigned long start, int num_pages)) +{ + BUG_ON(!PAGE_ALIGNED(layout->base)); + BUG_ON(!PAGE_ALIGNED(layout->ro_size)); + BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size)); + set_memory((unsigned long)layout->base + layout->ro_size, + (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT); +} + +static void frob_writable_data(const struct module_layout *layout, + int (*set_memory)(unsigned long start, int num_pages)) +{ + BUG_ON(!PAGE_ALIGNED(layout->base)); + BUG_ON(!PAGE_ALIGNED(layout->ro_after_init_size)); + BUG_ON(!PAGE_ALIGNED(layout->size)); + set_memory((unsigned long)layout->base + layout->ro_after_init_size, + (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT); +} + +void module_enable_ro(const struct module *mod, bool after_init) +{ + if (!rodata_enabled) + return; + + set_vm_flush_reset_perms(mod->core_layout.base); + set_vm_flush_reset_perms(mod->init_layout.base); + frob_text(&mod->core_layout, set_memory_ro); + + frob_rodata(&mod->core_layout, set_memory_ro); + frob_text(&mod->init_layout, set_memory_ro); + frob_rodata(&mod->init_layout, set_memory_ro); + + if (after_init) + frob_ro_after_init(&mod->core_layout, set_memory_ro); +} + +void module_enable_nx(const struct module *mod) +{ + frob_rodata(&mod->core_layout, set_memory_nx); + frob_ro_after_init(&mod->core_layout, set_memory_nx); + frob_writable_data(&mod->core_layout, set_memory_nx); + frob_rodata(&mod->init_layout, set_memory_nx); + frob_writable_data(&mod->init_layout, set_memory_nx); +} + +int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, + char *secstrings, struct module *mod) +{ + const unsigned long shf_wx = SHF_WRITE | SHF_EXECINSTR; + int i; + + for (i = 0; i < hdr->e_shnum; i++) { + if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) { + pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n", + mod->name, secstrings + sechdrs[i].sh_name, i); + return -ENOEXEC; + } + } + + return 0; +}
No functional change. This patch migrates code that makes module text and rodata memory read-only and non-text memory non-executable from core module code into kernel/module/strict_rwx.c. Signed-off-by: Aaron Tomlin <atomlin@redhat.com> --- kernel/module/Makefile | 1 + kernel/module/internal.h | 32 ++++++++++++ kernel/module/main.c | 99 +------------------------------------- kernel/module/strict_rwx.c | 85 ++++++++++++++++++++++++++++++++ 4 files changed, 120 insertions(+), 97 deletions(-) create mode 100644 kernel/module/strict_rwx.c