diff options
Diffstat (limited to 'fs/binfmt_elf.c')
| -rw-r--r-- | fs/binfmt_elf.c | 356 |
1 files changed, 192 insertions, 164 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index a43897b03ce9..3eb734c192e9 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -46,7 +46,7 @@ #include <linux/cred.h> #include <linux/dax.h> #include <linux/uaccess.h> -#include <linux/rseq.h> +#include <uapi/linux/rseq.h> #include <asm/param.h> #include <asm/page.h> @@ -68,12 +68,6 @@ static int load_elf_binary(struct linux_binprm *bprm); -#ifdef CONFIG_USELIB -static int load_elf_library(struct file *); -#else -#define load_elf_library NULL -#endif - /* * If we don't support core dumping, then supply a NULL so we * don't even try. @@ -101,7 +95,6 @@ static int elf_core_dump(struct coredump_params *cprm); static struct linux_binfmt elf_format = { .module = THIS_MODULE, .load_binary = load_elf_binary, - .load_shlib = load_elf_library, #ifdef CONFIG_COREDUMP .core_dump = elf_core_dump, .min_coredump = ELF_EXEC_PAGESIZE, @@ -110,6 +103,21 @@ static struct linux_binfmt elf_format = { #define BAD_ADDR(x) (unlikely((unsigned long)(x) >= TASK_SIZE)) +static inline void elf_coredump_set_mm_eflags(struct mm_struct *mm, u32 flags) +{ +#ifdef CONFIG_ARCH_HAS_ELF_CORE_EFLAGS + mm->saved_e_flags = flags; +#endif +} + +static inline u32 elf_coredump_get_mm_eflags(struct mm_struct *mm, u32 flags) +{ +#ifdef CONFIG_ARCH_HAS_ELF_CORE_EFLAGS + flags = mm->saved_e_flags; +#endif + return flags; +} + /* * We need to explicitly zero any trailing portion of the page that follows * p_filesz when it ends before the page ends (e.g. bss), otherwise this @@ -258,6 +266,12 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec, #ifdef ELF_HWCAP2 NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2); #endif +#ifdef ELF_HWCAP3 + NEW_AUX_ENT(AT_HWCAP3, ELF_HWCAP3); +#endif +#ifdef ELF_HWCAP4 + NEW_AUX_ENT(AT_HWCAP4, ELF_HWCAP4); +#endif NEW_AUX_ENT(AT_EXECFN, bprm->exec); if (k_platform) { NEW_AUX_ENT(AT_PLATFORM, @@ -520,7 +534,7 @@ static struct elf_phdr *load_elf_phdrs(const struct elfhdr *elf_ex, /* Sanity check the number of program headers... */ /* ...and their total size. */ size = sizeof(struct elf_phdr) * elf_ex->e_phnum; - if (size == 0 || size > 65536 || size > ELF_MIN_ALIGN) + if (size == 0 || size > 65536) goto out; elf_phdata = kmalloc(size, GFP_KERNEL); @@ -647,7 +661,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex, if (!elf_check_arch(interp_elf_ex) || elf_check_fdpic(interp_elf_ex)) goto out; - if (!interpreter->f_op->mmap) + if (!can_mmap_file(interpreter)) goto out; total_size = total_mapping_size(interp_elf_phdata, @@ -756,8 +770,7 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz, } #define NOTE_DATA_SZ SZ_1K -#define GNU_PROPERTY_TYPE_0_NAME "GNU" -#define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME)) +#define NOTE_NAME_SZ (sizeof(NN_GNU_PROPERTY_TYPE_0)) static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr, struct arch_elf_state *arch) @@ -794,7 +807,7 @@ static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr, if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 || note.nhdr.n_namesz != NOTE_NAME_SZ || strncmp(note.data + sizeof(note.nhdr), - GNU_PROPERTY_TYPE_0_NAME, n - sizeof(note.nhdr))) + NN_GNU_PROPERTY_TYPE_0, n - sizeof(note.nhdr))) return -ENOEXEC; off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ, @@ -825,6 +838,7 @@ static int load_elf_binary(struct linux_binprm *bprm) struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL; struct elf_phdr *elf_property_phdata = NULL; unsigned long elf_brk; + bool brk_moved = false; int retval, i; unsigned long elf_entry; unsigned long e_entry; @@ -849,7 +863,7 @@ static int load_elf_binary(struct linux_binprm *bprm) goto out; if (elf_check_fdpic(elf_ex)) goto out; - if (!bprm->file->f_op->mmap) + if (!can_mmap_file(bprm->file)) goto out; elf_phdata = load_elf_phdrs(elf_ex, bprm->file); @@ -1003,7 +1017,8 @@ out_free_interp: if (elf_read_implies_exec(*elf_ex, executable_stack)) current->personality |= READ_IMPLIES_EXEC; - if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) + const int snapshot_randomize_va_space = READ_ONCE(randomize_va_space); + if (!(current->personality & ADDR_NO_RANDOMIZE) && snapshot_randomize_va_space) current->flags |= PF_RANDOMIZE; setup_new_exec(bprm); @@ -1061,15 +1076,49 @@ out_free_interp: * Header for ET_DYN binaries to calculate the * randomization (load_bias) for all the LOAD * Program Headers. + */ + + /* + * Calculate the entire size of the ELF mapping + * (total_size), used for the initial mapping, + * due to load_addr_set which is set to true later + * once the initial mapping is performed. + * + * Note that this is only sensible when the LOAD + * segments are contiguous (or overlapping). If + * used for LOADs that are far apart, this would + * cause the holes between LOADs to be mapped, + * running the risk of having the mapping fail, + * as it would be larger than the ELF file itself. + * + * As a result, only ET_DYN does this, since + * some ET_EXEC (e.g. ia64) may have large virtual + * memory holes between LOADs. * - * There are effectively two types of ET_DYN - * binaries: programs (i.e. PIE: ET_DYN with INTERP) - * and loaders (ET_DYN without INTERP, since they - * _are_ the ELF interpreter). The loaders must - * be loaded away from programs since the program - * may otherwise collide with the loader (especially - * for ET_EXEC which does not have a randomized - * position). For example to handle invocations of + */ + total_size = total_mapping_size(elf_phdata, + elf_ex->e_phnum); + if (!total_size) { + retval = -EINVAL; + goto out_free_dentry; + } + + /* Calculate any requested alignment. */ + alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum); + + /** + * DOC: PIE handling + * + * There are effectively two types of ET_DYN ELF + * binaries: programs (i.e. PIE: ET_DYN with + * PT_INTERP) and loaders (i.e. static PIE: ET_DYN + * without PT_INTERP, usually the ELF interpreter + * itself). Loaders must be loaded away from programs + * since the program may otherwise collide with the + * loader (especially for ET_EXEC which does not have + * a randomized position). + * + * For example, to handle invocations of * "./ld.so someprog" to test out a new version of * the loader, the subsequent program that the * loader loads must avoid the loader itself, so @@ -1082,17 +1131,49 @@ out_free_interp: * ELF_ET_DYN_BASE and loaders are loaded into the * independently randomized mmap region (0 load_bias * without MAP_FIXED nor MAP_FIXED_NOREPLACE). + * + * See below for "brk" handling details, which is + * also affected by program vs loader and ASLR. */ if (interpreter) { + /* On ET_DYN with PT_INTERP, we do the ASLR. */ load_bias = ELF_ET_DYN_BASE; if (current->flags & PF_RANDOMIZE) load_bias += arch_mmap_rnd(); - alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum); + /* Adjust alignment as requested. */ if (alignment) load_bias &= ~(alignment - 1); elf_flags |= MAP_FIXED_NOREPLACE; - } else - load_bias = 0; + } else { + /* + * For ET_DYN without PT_INTERP, we rely on + * the architectures's (potentially ASLR) mmap + * base address (via a load_bias of 0). + * + * When a large alignment is requested, we + * must do the allocation at address "0" right + * now to discover where things will load so + * that we can adjust the resulting alignment. + * In this case (load_bias != 0), we can use + * MAP_FIXED_NOREPLACE to make sure the mapping + * doesn't collide with anything. + */ + if (alignment > ELF_MIN_ALIGN) { + load_bias = elf_load(bprm->file, 0, elf_ppnt, + elf_prot, elf_flags, total_size); + if (BAD_ADDR(load_bias)) { + retval = IS_ERR_VALUE(load_bias) ? + PTR_ERR((void*)load_bias) : -EINVAL; + goto out_free_dentry; + } + vm_munmap(load_bias, total_size); + /* Adjust alignment as requested. */ + if (alignment) + load_bias &= ~(alignment - 1); + elf_flags |= MAP_FIXED_NOREPLACE; + } else + load_bias = 0; + } /* * Since load_bias is used for all subsequent loading @@ -1102,31 +1183,6 @@ out_free_interp: * is then page aligned. */ load_bias = ELF_PAGESTART(load_bias - vaddr); - - /* - * Calculate the entire size of the ELF mapping - * (total_size), used for the initial mapping, - * due to load_addr_set which is set to true later - * once the initial mapping is performed. - * - * Note that this is only sensible when the LOAD - * segments are contiguous (or overlapping). If - * used for LOADs that are far apart, this would - * cause the holes between LOADs to be mapped, - * running the risk of having the mapping fail, - * as it would be larger than the ELF file itself. - * - * As a result, only ET_DYN does this, since - * some ET_EXEC (e.g. ia64) may have large virtual - * memory holes between LOADs. - * - */ - total_size = total_mapping_size(elf_phdata, - elf_ex->e_phnum); - if (!total_size) { - retval = -EINVAL; - goto out_free_dentry; - } } error = elf_load(bprm->file, load_bias + vaddr, elf_ppnt, @@ -1194,8 +1250,6 @@ out_free_interp: start_data += load_bias; end_data += load_bias; - current->mm->start_brk = current->mm->brk = ELF_PAGEALIGN(elf_brk); - if (interpreter) { elf_entry = load_elf_interp(interp_elf_ex, interpreter, @@ -1216,7 +1270,7 @@ out_free_interp: } reloc_func_desc = interp_load_addr; - allow_write_access(interpreter); + exe_file_allow_write_access(interpreter); fput(interpreter); kfree(interp_elf_ex); @@ -1251,27 +1305,46 @@ out_free_interp: mm->end_data = end_data; mm->start_stack = bprm->p; - if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) { + elf_coredump_set_mm_eflags(mm, elf_ex->e_flags); + + /** + * DOC: "brk" handling + * + * For architectures with ELF randomization, when executing a + * loader directly (i.e. static PIE: ET_DYN without PT_INTERP), + * move the brk area out of the mmap region and into the unused + * ELF_ET_DYN_BASE region. Since "brk" grows up it may collide + * early with the stack growing down or other regions being put + * into the mmap region by the kernel (e.g. vdso). + * + * In the CONFIG_COMPAT_BRK case, though, everything is turned + * off because we're not allowed to move the brk at all. + */ + if (!IS_ENABLED(CONFIG_COMPAT_BRK) && + IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && + elf_ex->e_type == ET_DYN && !interpreter) { + elf_brk = ELF_ET_DYN_BASE; + /* This counts as moving the brk, so let brk(2) know. */ + brk_moved = true; + } + mm->start_brk = mm->brk = ELF_PAGEALIGN(elf_brk); + + if ((current->flags & PF_RANDOMIZE) && snapshot_randomize_va_space > 1) { /* - * For architectures with ELF randomization, when executing - * a loader directly (i.e. no interpreter listed in ELF - * headers), move the brk area out of the mmap region - * (since it grows up, and may collide early with the stack - * growing down), and into the unused ELF_ET_DYN_BASE region. + * If we didn't move the brk to ELF_ET_DYN_BASE (above), + * leave a gap between .bss and brk. */ - if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && - elf_ex->e_type == ET_DYN && !interpreter) { - mm->brk = mm->start_brk = ELF_ET_DYN_BASE; - } else { - /* Otherwise leave a gap between .bss and brk. */ + if (!brk_moved) mm->brk = mm->start_brk = mm->brk + PAGE_SIZE; - } mm->brk = mm->start_brk = arch_randomize_brk(mm); + brk_moved = true; + } + #ifdef compat_brk_randomized + if (brk_moved) current->brk_randomized = 1; #endif - } if (current->personality & MMAP_PAGE_ZERO) { /* Why this, you ask??? Well SVr4 maps page 0 as read-only, @@ -1280,6 +1353,11 @@ out_free_interp: emulate the SVr4 behavior. Sigh. */ error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC, MAP_FIXED | MAP_PRIVATE, 0); + + retval = do_mseal(0, PAGE_SIZE, 0); + if (retval) + pr_warn_ratelimited("pid=%d, couldn't seal address 0, ret=%d.\n", + task_pid_nr(current), retval); } regs = current_pt_regs(); @@ -1308,7 +1386,7 @@ out_free_dentry: kfree(interp_elf_ex); kfree(interp_elf_phdata); out_free_file: - allow_write_access(interpreter); + exe_file_allow_write_access(interpreter); if (interpreter) fput(interpreter); out_free_ph: @@ -1316,75 +1394,6 @@ out_free_ph: goto out; } -#ifdef CONFIG_USELIB -/* This is really simpleminded and specialized - we are loading an - a.out library that is given an ELF header. */ -static int load_elf_library(struct file *file) -{ - struct elf_phdr *elf_phdata; - struct elf_phdr *eppnt; - int retval, error, i, j; - struct elfhdr elf_ex; - - error = -ENOEXEC; - retval = elf_read(file, &elf_ex, sizeof(elf_ex), 0); - if (retval < 0) - goto out; - - if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0) - goto out; - - /* First of all, some simple consistency checks */ - if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 || - !elf_check_arch(&elf_ex) || !file->f_op->mmap) - goto out; - if (elf_check_fdpic(&elf_ex)) - goto out; - - /* Now read in all of the header information */ - - j = sizeof(struct elf_phdr) * elf_ex.e_phnum; - /* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */ - - error = -ENOMEM; - elf_phdata = kmalloc(j, GFP_KERNEL); - if (!elf_phdata) - goto out; - - eppnt = elf_phdata; - error = -ENOEXEC; - retval = elf_read(file, eppnt, j, elf_ex.e_phoff); - if (retval < 0) - goto out_free_ph; - - for (j = 0, i = 0; i<elf_ex.e_phnum; i++) - if ((eppnt + i)->p_type == PT_LOAD) - j++; - if (j != 1) - goto out_free_ph; - - while (eppnt->p_type != PT_LOAD) - eppnt++; - - /* Now use mmap to map the library into memory. */ - error = elf_load(file, ELF_PAGESTART(eppnt->p_vaddr), - eppnt, - PROT_READ | PROT_WRITE | PROT_EXEC, - MAP_FIXED_NOREPLACE | MAP_PRIVATE, - 0); - - if (error != ELF_PAGESTART(eppnt->p_vaddr)) - goto out_free_ph; - - error = 0; - -out_free_ph: - kfree(elf_phdata); -out: - return error; -} -#endif /* #ifdef CONFIG_USELIB */ - #ifdef CONFIG_ELF_CORE /* * ELF core dumper @@ -1458,8 +1467,8 @@ static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset) phdr->p_align = 4; } -static void fill_note(struct memelfnote *note, const char *name, int type, - unsigned int sz, void *data) +static void __fill_note(struct memelfnote *note, const char *name, int type, + unsigned int sz, void *data) { note->name = name; note->type = type; @@ -1467,6 +1476,9 @@ static void fill_note(struct memelfnote *note, const char *name, int type, note->data = data; } +#define fill_note(note, type, sz, data) \ + __fill_note(note, NN_ ## type, NT_ ## type, sz, data) + /* * fill up all the fields in prstatus from the given task struct, except * registers which need to be filled up separately. @@ -1557,14 +1569,14 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm) do i += 2; while (auxv[i - 2] != AT_NULL); - fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv); + fill_note(note, AUXV, i * sizeof(elf_addr_t), auxv); } static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, const kernel_siginfo_t *siginfo) { copy_siginfo_to_external(csigdata, siginfo); - fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); + fill_note(note, SIGINFO, sizeof(*csigdata), csigdata); } /* @@ -1660,7 +1672,7 @@ static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm } size = name_curpos - (char *)data; - fill_note(note, "CORE", NT_FILE, size, data); + fill_note(note, FILE, size, data); return 0; } @@ -1721,8 +1733,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, regset_get(t->task, &view->regsets[0], sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg); - fill_note(&t->notes[0], "CORE", NT_PRSTATUS, - PRSTATUS_SIZE, &t->prstatus); + fill_note(&t->notes[0], PRSTATUS, PRSTATUS_SIZE, &t->prstatus); info->size += notesize(&t->notes[0]); do_thread_regset_writeback(t->task, &view->regsets[0]); @@ -1735,6 +1746,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, for (view_iter = 1; view_iter < view->n; ++view_iter) { const struct user_regset *regset = &view->regsets[view_iter]; int note_type = regset->core_note_type; + const char *note_name = regset->core_note_name; bool is_fpreg = note_type == NT_PRFPREG; void *data; int ret; @@ -1755,8 +1767,16 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, if (is_fpreg) SET_PR_FPVALID(&t->prstatus); - fill_note(&t->notes[note_iter], is_fpreg ? "CORE" : "LINUX", - note_type, ret, data); + /* There should be a note name, but if not, guess: */ + if (WARN_ON_ONCE(!note_name)) + note_name = "LINUX"; + else + /* Warn on non-legacy-compatible names, for now. */ + WARN_ON_ONCE(strcmp(note_name, + is_fpreg ? "CORE" : "LINUX")); + + __fill_note(&t->notes[note_iter], note_name, note_type, + ret, data); info->size += notesize(&t->notes[note_iter]); note_iter++; @@ -1775,8 +1795,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, fill_prstatus(&t->prstatus.common, p, signr); elf_core_copy_task_regs(p, &t->prstatus.pr_reg); - fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus), - &(t->prstatus)); + fill_note(&t->notes[0], PRSTATUS, sizeof(t->prstatus), &t->prstatus); info->size += notesize(&t->notes[0]); fpu = kzalloc(sizeof(elf_fpregset_t), GFP_KERNEL); @@ -1786,7 +1805,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t, } t->prstatus.pr_fpvalid = 1; - fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(*fpu), fpu); + fill_note(&t->notes[1], PRFPREG, sizeof(*fpu), fpu); info->size += notesize(&t->notes[1]); return 1; @@ -1802,11 +1821,13 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, struct elf_thread_core_info *t; struct elf_prpsinfo *psinfo; struct core_thread *ct; + u16 machine; + u32 flags; psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL); if (!psinfo) return 0; - fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo); + fill_note(&info->psinfo, PRPSINFO, sizeof(*psinfo), psinfo); #ifdef CORE_DUMP_USE_REGSET view = task_user_regset_view(dump_task); @@ -1829,30 +1850,37 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, return 0; } - /* - * Initialize the ELF file header. - */ - fill_elf_header(elf, phdrs, - view->e_machine, view->e_flags); + machine = view->e_machine; + flags = view->e_flags; #else view = NULL; info->thread_notes = 2; - fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS); + machine = ELF_ARCH; + flags = ELF_CORE_EFLAGS; #endif /* + * Override ELF e_flags with value taken from process, + * if arch needs that. + */ + flags = elf_coredump_get_mm_eflags(dump_task->mm, flags); + + /* + * Initialize the ELF file header. + */ + fill_elf_header(elf, phdrs, machine, flags); + + /* * Allocate a structure for each thread. */ - info->thread = kzalloc(offsetof(struct elf_thread_core_info, - notes[info->thread_notes]), - GFP_KERNEL); + info->thread = kzalloc(struct_size(info->thread, notes, info->thread_notes), + GFP_KERNEL); if (unlikely(!info->thread)) return 0; info->thread->task = dump_task; for (ct = dump_task->signal->core_state->dumper.next; ct; ct = ct->next) { - t = kzalloc(offsetof(struct elf_thread_core_info, - notes[info->thread_notes]), + t = kzalloc(struct_size(t, notes, info->thread_notes), GFP_KERNEL); if (unlikely(!t)) return 0; @@ -2006,7 +2034,7 @@ static int elf_core_dump(struct coredump_params *cprm) { size_t sz = info.size; - /* For cell spufs */ + /* For cell spufs and x86 xstate */ sz += elf_coredump_extra_notes_size(); phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL); @@ -2070,7 +2098,7 @@ static int elf_core_dump(struct coredump_params *cprm) if (!write_note_info(&info, cprm)) goto end_coredump; - /* For cell spufs */ + /* For cell spufs and x86 xstate */ if (elf_coredump_extra_notes_write(cprm)) goto end_coredump; @@ -2117,5 +2145,5 @@ core_initcall(init_elf_binfmt); module_exit(exit_elf_binfmt); #ifdef CONFIG_BINFMT_ELF_KUNIT_TEST -#include "binfmt_elf_test.c" +#include "tests/binfmt_elf_kunit.c" #endif |