diff options
Diffstat (limited to 'arch/arm64/kernel/module.c')
| -rw-r--r-- | arch/arm64/kernel/module.c | 265 |
1 files changed, 91 insertions, 174 deletions
diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c index dd851297596e..24adb581af0e 100644 --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -12,143 +12,18 @@ #include <linux/bitops.h> #include <linux/elf.h> #include <linux/ftrace.h> -#include <linux/gfp.h> #include <linux/kasan.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/moduleloader.h> #include <linux/random.h> #include <linux/scs.h> -#include <linux/vmalloc.h> #include <asm/alternative.h> #include <asm/insn.h> #include <asm/scs.h> #include <asm/sections.h> - -static u64 module_direct_base __ro_after_init = 0; -static u64 module_plt_base __ro_after_init = 0; - -/* - * Choose a random page-aligned base address for a window of 'size' bytes which - * entirely contains the interval [start, end - 1]. - */ -static u64 __init random_bounding_box(u64 size, u64 start, u64 end) -{ - u64 max_pgoff, pgoff; - - if ((end - start) >= size) - return 0; - - max_pgoff = (size - (end - start)) / PAGE_SIZE; - pgoff = get_random_u32_inclusive(0, max_pgoff); - - return start - pgoff * PAGE_SIZE; -} - -/* - * Modules may directly reference data and text anywhere within the kernel - * image and other modules. References using PREL32 relocations have a +/-2G - * range, and so we need to ensure that the entire kernel image and all modules - * fall within a 2G window such that these are always within range. - * - * Modules may directly branch to functions and code within the kernel text, - * and to functions and code within other modules. These branches will use - * CALL26/JUMP26 relocations with a +/-128M range. Without PLTs, we must ensure - * that the entire kernel text and all module text falls within a 128M window - * such that these are always within range. With PLTs, we can expand this to a - * 2G window. - * - * We chose the 128M region to surround the entire kernel image (rather than - * just the text) as using the same bounds for the 128M and 2G regions ensures - * by construction that we never select a 128M region that is not a subset of - * the 2G region. For very large and unusual kernel configurations this means - * we may fall back to PLTs where they could have been avoided, but this keeps - * the logic significantly simpler. - */ -static int __init module_init_limits(void) -{ - u64 kernel_end = (u64)_end; - u64 kernel_start = (u64)_text; - u64 kernel_size = kernel_end - kernel_start; - - /* - * The default modules region is placed immediately below the kernel - * image, and is large enough to use the full 2G relocation range. - */ - BUILD_BUG_ON(KIMAGE_VADDR != MODULES_END); - BUILD_BUG_ON(MODULES_VSIZE < SZ_2G); - - if (!kaslr_enabled()) { - if (kernel_size < SZ_128M) - module_direct_base = kernel_end - SZ_128M; - if (kernel_size < SZ_2G) - module_plt_base = kernel_end - SZ_2G; - } else { - u64 min = kernel_start; - u64 max = kernel_end; - - if (IS_ENABLED(CONFIG_RANDOMIZE_MODULE_REGION_FULL)) { - pr_info("2G module region forced by RANDOMIZE_MODULE_REGION_FULL\n"); - } else { - module_direct_base = random_bounding_box(SZ_128M, min, max); - if (module_direct_base) { - min = module_direct_base; - max = module_direct_base + SZ_128M; - } - } - - module_plt_base = random_bounding_box(SZ_2G, min, max); - } - - pr_info("%llu pages in range for non-PLT usage", - module_direct_base ? (SZ_128M - kernel_size) / PAGE_SIZE : 0); - pr_info("%llu pages in range for PLT usage", - module_plt_base ? (SZ_2G - kernel_size) / PAGE_SIZE : 0); - - return 0; -} -subsys_initcall(module_init_limits); - -void *module_alloc(unsigned long size) -{ - void *p = NULL; - - /* - * Where possible, prefer to allocate within direct branch range of the - * kernel such that no PLTs are necessary. - */ - if (module_direct_base) { - p = __vmalloc_node_range(size, MODULE_ALIGN, - module_direct_base, - module_direct_base + SZ_128M, - GFP_KERNEL | __GFP_NOWARN, - PAGE_KERNEL, 0, NUMA_NO_NODE, - __builtin_return_address(0)); - } - - if (!p && module_plt_base) { - p = __vmalloc_node_range(size, MODULE_ALIGN, - module_plt_base, - module_plt_base + SZ_2G, - GFP_KERNEL | __GFP_NOWARN, - PAGE_KERNEL, 0, NUMA_NO_NODE, - __builtin_return_address(0)); - } - - if (!p) { - pr_warn_ratelimited("%s: unable to allocate memory\n", - __func__); - } - - if (p && (kasan_alloc_module_shadow(p, size, GFP_KERNEL) < 0)) { - vfree(p); - return NULL; - } - - /* Memory is intended to be executable, reset the pointer tag. */ - return kasan_reset_tag(p); -} +#include <asm/text-patching.h> enum aarch64_reloc_op { RELOC_OP_NONE, @@ -174,7 +49,17 @@ static u64 do_reloc(enum aarch64_reloc_op reloc_op, __le32 *place, u64 val) return 0; } -static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len) +#define WRITE_PLACE(place, val, mod) do { \ + __typeof__(val) __val = (val); \ + \ + if (mod->state == MODULE_STATE_UNFORMED) \ + *(place) = __val; \ + else \ + aarch64_insn_copy(place, &(__val), sizeof(*place)); \ +} while (0) + +static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len, + struct module *me) { s64 sval = do_reloc(op, place, val); @@ -192,7 +77,7 @@ static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len) switch (len) { case 16: - *(s16 *)place = sval; + WRITE_PLACE((s16 *)place, sval, me); switch (op) { case RELOC_OP_ABS: if (sval < 0 || sval > U16_MAX) @@ -208,7 +93,7 @@ static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len) } break; case 32: - *(s32 *)place = sval; + WRITE_PLACE((s32 *)place, sval, me); switch (op) { case RELOC_OP_ABS: if (sval < 0 || sval > U32_MAX) @@ -224,7 +109,7 @@ static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len) } break; case 64: - *(s64 *)place = sval; + WRITE_PLACE((s64 *)place, sval, me); break; default: pr_err("Invalid length (%d) for data relocation\n", len); @@ -239,7 +124,8 @@ enum aarch64_insn_movw_imm_type { }; static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, - int lsb, enum aarch64_insn_movw_imm_type imm_type) + int lsb, enum aarch64_insn_movw_imm_type imm_type, + struct module *me) { u64 imm; s64 sval; @@ -271,7 +157,7 @@ static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, /* Update the instruction with the new encoding. */ insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm); - *place = cpu_to_le32(insn); + WRITE_PLACE(place, cpu_to_le32(insn), me); if (imm > U16_MAX) return -ERANGE; @@ -280,7 +166,8 @@ static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val, } static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *place, u64 val, - int lsb, int len, enum aarch64_insn_imm_type imm_type) + int lsb, int len, enum aarch64_insn_imm_type imm_type, + struct module *me) { u64 imm, imm_mask; s64 sval; @@ -296,7 +183,7 @@ static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *place, u64 val, /* Update the instruction's immediate field. */ insn = aarch64_insn_encode_immediate(imm_type, insn, imm); - *place = cpu_to_le32(insn); + WRITE_PLACE(place, cpu_to_le32(insn), me); /* * Extract the upper value bits (including the sign bit) and @@ -315,17 +202,17 @@ static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *place, u64 val, } static int reloc_insn_adrp(struct module *mod, Elf64_Shdr *sechdrs, - __le32 *place, u64 val) + __le32 *place, u64 val, struct module *me) { u32 insn; if (!is_forbidden_offset_for_adrp(place)) return reloc_insn_imm(RELOC_OP_PAGE, place, val, 12, 21, - AARCH64_INSN_IMM_ADR); + AARCH64_INSN_IMM_ADR, me); /* patch ADRP to ADR if it is in range */ if (!reloc_insn_imm(RELOC_OP_PREL, place, val & ~0xfff, 0, 21, - AARCH64_INSN_IMM_ADR)) { + AARCH64_INSN_IMM_ADR, me)) { insn = le32_to_cpu(*place); insn &= ~BIT(31); } else { @@ -337,7 +224,7 @@ static int reloc_insn_adrp(struct module *mod, Elf64_Shdr *sechdrs, AARCH64_INSN_BRANCH_NOLINK); } - *place = cpu_to_le32(insn); + WRITE_PLACE(place, cpu_to_le32(insn), me); return 0; } @@ -381,23 +268,23 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, /* Data relocations. */ case R_AARCH64_ABS64: overflow_check = false; - ovf = reloc_data(RELOC_OP_ABS, loc, val, 64); + ovf = reloc_data(RELOC_OP_ABS, loc, val, 64, me); break; case R_AARCH64_ABS32: - ovf = reloc_data(RELOC_OP_ABS, loc, val, 32); + ovf = reloc_data(RELOC_OP_ABS, loc, val, 32, me); break; case R_AARCH64_ABS16: - ovf = reloc_data(RELOC_OP_ABS, loc, val, 16); + ovf = reloc_data(RELOC_OP_ABS, loc, val, 16, me); break; case R_AARCH64_PREL64: overflow_check = false; - ovf = reloc_data(RELOC_OP_PREL, loc, val, 64); + ovf = reloc_data(RELOC_OP_PREL, loc, val, 64, me); break; case R_AARCH64_PREL32: - ovf = reloc_data(RELOC_OP_PREL, loc, val, 32); + ovf = reloc_data(RELOC_OP_PREL, loc, val, 32, me); break; case R_AARCH64_PREL16: - ovf = reloc_data(RELOC_OP_PREL, loc, val, 16); + ovf = reloc_data(RELOC_OP_PREL, loc, val, 16, me); break; /* MOVW instruction relocations. */ @@ -406,88 +293,88 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, fallthrough; case R_AARCH64_MOVW_UABS_G0: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_UABS_G1_NC: overflow_check = false; fallthrough; case R_AARCH64_MOVW_UABS_G1: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_UABS_G2_NC: overflow_check = false; fallthrough; case R_AARCH64_MOVW_UABS_G2: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_UABS_G3: /* We're using the top bits so we can't overflow. */ overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 48, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_SABS_G0: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0, - AARCH64_INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_SABS_G1: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16, - AARCH64_INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_SABS_G2: ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32, - AARCH64_INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_PREL_G0_NC: overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G0: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0, - AARCH64_INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_PREL_G1_NC: overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G1: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16, - AARCH64_INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_PREL_G2_NC: overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32, - AARCH64_INSN_IMM_MOVKZ); + AARCH64_INSN_IMM_MOVKZ, me); break; case R_AARCH64_MOVW_PREL_G2: ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32, - AARCH64_INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; case R_AARCH64_MOVW_PREL_G3: /* We're using the top bits so we can't overflow. */ overflow_check = false; ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 48, - AARCH64_INSN_IMM_MOVNZ); + AARCH64_INSN_IMM_MOVNZ, me); break; /* Immediate instruction relocations. */ case R_AARCH64_LD_PREL_LO19: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19, - AARCH64_INSN_IMM_19); + AARCH64_INSN_IMM_19, me); break; case R_AARCH64_ADR_PREL_LO21: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 0, 21, - AARCH64_INSN_IMM_ADR); + AARCH64_INSN_IMM_ADR, me); break; case R_AARCH64_ADR_PREL_PG_HI21_NC: overflow_check = false; fallthrough; case R_AARCH64_ADR_PREL_PG_HI21: - ovf = reloc_insn_adrp(me, sechdrs, loc, val); + ovf = reloc_insn_adrp(me, sechdrs, loc, val, me); if (ovf && ovf != -ERANGE) return ovf; break; @@ -495,46 +382,46 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, case R_AARCH64_LDST8_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 0, 12, - AARCH64_INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST16_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 1, 11, - AARCH64_INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST32_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 2, 10, - AARCH64_INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST64_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 3, 9, - AARCH64_INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_LDST128_ABS_LO12_NC: overflow_check = false; ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 4, 8, - AARCH64_INSN_IMM_12); + AARCH64_INSN_IMM_12, me); break; case R_AARCH64_TSTBR14: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 14, - AARCH64_INSN_IMM_14); + AARCH64_INSN_IMM_14, me); break; case R_AARCH64_CONDBR19: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19, - AARCH64_INSN_IMM_19); + AARCH64_INSN_IMM_19, me); break; case R_AARCH64_JUMP26: case R_AARCH64_CALL26: ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26, - AARCH64_INSN_IMM_26); + AARCH64_INSN_IMM_26, me); if (ovf == -ERANGE) { val = module_emit_plt_entry(me, sechdrs, loc, &rel[i], sym); if (!val) return -ENOEXEC; ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, - 26, AARCH64_INSN_IMM_26); + 26, AARCH64_INSN_IMM_26, me); } break; @@ -579,6 +466,17 @@ static int module_init_ftrace_plt(const Elf_Ehdr *hdr, __init_plt(&plts[FTRACE_PLT_IDX], FTRACE_ADDR); mod->arch.ftrace_trampolines = plts; + + s = find_section(hdr, sechdrs, ".init.text.ftrace_trampoline"); + if (!s) + return -ENOEXEC; + + plts = (void *)s->sh_addr; + + __init_plt(&plts[FTRACE_PLT_IDX], FTRACE_ADDR); + + mod->arch.init_ftrace_trampolines = plts; + #endif return 0; } @@ -588,14 +486,33 @@ int module_finalize(const Elf_Ehdr *hdr, struct module *me) { const Elf_Shdr *s; + int ret; + s = find_section(hdr, sechdrs, ".altinstructions"); - if (s) - apply_alternatives_module((void *)s->sh_addr, s->sh_size); + if (s) { + ret = apply_alternatives_module((void *)s->sh_addr, s->sh_size); + if (ret < 0) { + pr_err("module %s: error occurred when applying alternatives\n", me->name); + return ret; + } + } if (scs_is_dynamic()) { s = find_section(hdr, sechdrs, ".init.eh_frame"); - if (s) - scs_patch((void *)s->sh_addr, s->sh_size); + if (s) { + /* + * Because we can reject modules that are malformed + * so SCS patching fails, skip dry run and try to patch + * it in place. If patching fails, the module would not + * be loaded anyway. + */ + ret = __pi_scs_patch((void *)s->sh_addr, s->sh_size, true); + if (ret) { + pr_err("module %s: error occurred during dynamic SCS patching (%d)\n", + me->name, ret); + return -ENOEXEC; + } + } } return module_init_ftrace_plt(hdr, sechdrs, me); |