From 0c133b1e78cd34dd9d18da707dc6f46170e9129e Mon Sep 17 00:00:00 2001 From: "Mike Rapoport (Microsoft)" Date: Wed, 23 Oct 2024 19:27:07 +0300 Subject: module: prepare to handle ROX allocations for text In order to support ROX allocations for module text, it is necessary to handle modifications to the code, such as relocations and alternatives patching, without write access to that memory. One option is to use text patching, but this would make module loading extremely slow and will expose executable code that is not finally formed. A better way is to have memory allocated with ROX permissions contain invalid instructions and keep a writable, but not executable copy of the module text. The relocations and alternative patches would be done on the writable copy using the addresses of the ROX memory. Once the module is completely ready, the updated text will be copied to ROX memory using text patching in one go and the writable copy will be freed. Add support for that to module initialization code and provide necessary interfaces in execmem. Link: https://lkml.kernel.org/r/20241023162711.2579610-5-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Reviewd-by: Luis Chamberlain Tested-by: kdevops Cc: Andreas Larsson Cc: Andy Lutomirski Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Borislav Petkov (AMD) Cc: Brian Cain Cc: Catalin Marinas Cc: Christophe Leroy Cc: Christoph Hellwig Cc: Dave Hansen Cc: Dinh Nguyen Cc: Geert Uytterhoeven Cc: Guo Ren Cc: Helge Deller Cc: Huacai Chen Cc: Ingo Molnar Cc: Johannes Berg Cc: John Paul Adrian Glaubitz Cc: Kent Overstreet Cc: Liam R. Howlett Cc: Mark Rutland Cc: Masami Hiramatsu (Google) Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Oleg Nesterov Cc: Palmer Dabbelt Cc: Peter Zijlstra Cc: Richard Weinberger Cc: Russell King Cc: Song Liu Cc: Stafford Horne Cc: Steven Rostedt (Google) Cc: Suren Baghdasaryan Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Uladzislau Rezki (Sony) Cc: Vineet Gupta Cc: Will Deacon Signed-off-by: Andrew Morton --- include/linux/module.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 88ecc5e9f523..2a9386cbdf85 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -367,6 +367,8 @@ enum mod_mem_type { struct module_memory { void *base; + void *rw_copy; + bool is_rox; unsigned int size; #ifdef CONFIG_MODULES_TREE_LOOKUP @@ -767,6 +769,15 @@ static inline bool is_livepatch_module(struct module *mod) void set_module_sig_enforced(void); +void *__module_writable_address(struct module *mod, void *loc); + +static inline void *module_writable_address(struct module *mod, void *loc) +{ + if (!IS_ENABLED(CONFIG_ARCH_HAS_EXECMEM_ROX) || !mod) + return loc; + return __module_writable_address(mod, loc); +} + #else /* !CONFIG_MODULES... */ static inline struct module *__module_address(unsigned long addr) @@ -874,6 +885,11 @@ static inline bool module_is_coming(struct module *mod) { return false; } + +static inline void *module_writable_address(struct module *mod, void *loc) +{ + return loc; +} #endif /* CONFIG_MODULES */ #ifdef CONFIG_SYSFS -- cgit v1.2.3 From 054a9cd395a79f4a5595f2cd24542e9bca8723c8 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Wed, 20 Nov 2024 08:56:52 +0900 Subject: modpost: rename alias symbol for MODULE_DEVICE_TABLE() This commit renames the alias symbol, __mod____device_table to __mod_device_table____. This change simplifies the code slightly, as there is no longer a need to check both the prefix and suffix. Signed-off-by: Masahiro Yamada --- include/linux/module.h | 2 +- scripts/mod/file2alias.c | 17 +++++++---------- 2 files changed, 8 insertions(+), 11 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 88ecc5e9f523..3dd79a3d0cbf 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -247,7 +247,7 @@ extern void cleanup_module(void); #ifdef MODULE /* Creates an alias so file2alias.c can find device table. */ #define MODULE_DEVICE_TABLE(type, name) \ -extern typeof(name) __mod_##type##__##name##_device_table \ +extern typeof(name) __mod_device_table__##type##__##name \ __attribute__ ((unused, alias(__stringify(name)))) #else /* !MODULE */ #define MODULE_DEVICE_TABLE(type, name) diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 038b2ab79e11..fc4bbeea1268 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -123,7 +123,7 @@ typedef struct { #include "../../include/linux/mod_devicetable.h" struct devtable { - const char *device_id; /* name of table, __mod___*_device_table. */ + const char *device_id; unsigned long id_size; void (*do_entry)(struct module *mod, void *symval); }; @@ -190,7 +190,7 @@ static void device_id_check(const char *modname, const char *device_id, int i; if (size % id_size || size < id_size) { - fatal("%s: sizeof(struct %s_device_id)=%lu is not a modulo of the size of section __mod_%s___device_table=%lu.\n" + fatal("%s: sizeof(struct %s_device_id)=%lu is not a modulo of the size of section __mod_device_table__%s__=%lu.\n" "Fix definition of struct %s_device_id in mod_devicetable.h\n", modname, device_id, id_size, device_id, size, device_id); } @@ -1505,6 +1505,7 @@ void handle_moddevtable(struct module *mod, struct elf_info *info, char *zeros = NULL; const char *type, *name; size_t typelen; + static const char *prefix = "__mod_device_table__"; /* We're looking for a section relative symbol */ if (!sym->st_shndx || get_secindex(info, sym) >= info->num_sections) @@ -1514,15 +1515,11 @@ void handle_moddevtable(struct module *mod, struct elf_info *info, if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT) return; - /* All our symbols are of form __mod____device_table. */ - if (!strstarts(symname, "__mod_")) - return; - type = symname + strlen("__mod_"); - typelen = strlen(type); - if (typelen < strlen("_device_table")) - return; - if (strcmp(type + typelen - strlen("_device_table"), "_device_table")) + /* All our symbols are of form __mod_device_table____. */ + if (!strstarts(symname, prefix)) return; + type = symname + strlen(prefix); + name = strstr(type, "__"); if (!name) return; -- cgit v1.2.3