[PATCH 10/13] modules, jitalloc: prepare to allocate executable memory as ROX
From: Mike Rapoport <rppt@kernel.org>
Date: 2023-06-01 10:19:04
Also in:
bpf, linux-arm-kernel, linux-mips, linux-modules, linux-riscv, linux-s390, linux-trace-kernel, lkml, loongarch, netdev, sparclinux
Subsystem:
memory management, module support, the rest · Maintainers:
Andrew Morton, Luis Chamberlain, Petr Pavlu, Daniel Gomez, Sami Tolvanen, Linus Torvalds
From: "Mike Rapoport (IBM)" <rppt@kernel.org> When executable memory will be allocated as ROX it won't be possible to update it using memset() and memcpy(). Introduce jit_update_copy() and jit_update_set() APIs and use them in modules loading code instead of memcpy() and memset(). Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> --- include/linux/jitalloc.h | 2 ++ kernel/module/main.c | 19 ++++++++++++++----- mm/jitalloc.c | 20 ++++++++++++++++++++ 3 files changed, 36 insertions(+), 5 deletions(-)
diff --git a/include/linux/jitalloc.h b/include/linux/jitalloc.h
index 7f8cafb3cfe9..0ba5ef785a85 100644
--- a/include/linux/jitalloc.h
+++ b/include/linux/jitalloc.h@@ -55,6 +55,8 @@ struct jit_alloc_params *jit_alloc_arch_params(void); void jit_free(void *buf); void *jit_text_alloc(size_t len); void *jit_data_alloc(size_t len); +void jit_update_copy(void *buf, void *new_buf, size_t len); +void jit_update_set(void *buf, int c, size_t len); #ifdef CONFIG_JIT_ALLOC void jit_alloc_init(void);
diff --git a/kernel/module/main.c b/kernel/module/main.c
index 91477aa5f671..9f0711c42aa2 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c@@ -1197,9 +1197,19 @@ void __weak module_arch_freeing_init(struct module *mod) static void *module_memory_alloc(unsigned int size, enum mod_mem_type type) { - if (mod_mem_type_is_data(type)) - return jit_data_alloc(size); - return jit_text_alloc(size); + void *p; + + if (mod_mem_type_is_data(type)) { + p = jit_data_alloc(size); + if (p) + memset(p, 0, size); + } else { + p = jit_text_alloc(size); + if (p) + jit_update_set(p, 0, size); + } + + return p; } static void module_memory_free(void *ptr, enum mod_mem_type type)
@@ -2223,7 +2233,6 @@ static int move_module(struct module *mod, struct load_info *info) t = type; goto out_enomem; } - memset(ptr, 0, mod->mem[type].size); mod->mem[type].base = ptr; }
@@ -2251,7 +2260,7 @@ static int move_module(struct module *mod, struct load_info *info) ret = -ENOEXEC; goto out_enomem; } - memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size); + jit_update_copy(dest, (void *)shdr->sh_addr, shdr->sh_size); } /* * Update the userspace copy's ELF section address to point to
diff --git a/mm/jitalloc.c b/mm/jitalloc.c
index 16fd715d501a..a8ae64364d56 100644
--- a/mm/jitalloc.c
+++ b/mm/jitalloc.c@@ -7,6 +7,16 @@ static struct jit_alloc_params jit_alloc_params; +static inline void jit_text_poke_copy(void *dst, const void *src, size_t len) +{ + memcpy(dst, src, len); +} + +static inline void jit_text_poke_set(void *addr, int c, size_t len) +{ + memset(addr, c, len); +} + static void *jit_alloc(size_t len, unsigned int alignment, pgprot_t pgprot, unsigned long start, unsigned long end, unsigned long fallback_start, unsigned long fallback_end,
@@ -86,6 +96,16 @@ void *jit_data_alloc(size_t len) fallback_start, fallback_end, kasan); } +void jit_update_copy(void *buf, void *new_buf, size_t len) +{ + jit_text_poke_copy(buf, new_buf, len); +} + +void jit_update_set(void *addr, int c, size_t len) +{ + jit_text_poke_set(addr, c, len); +} + struct jit_alloc_params * __weak jit_alloc_arch_params(void) { return NULL;
--
2.35.1