diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 01bcbe7fdebd..34d0d1e43f36 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1314,6 +1314,11 @@ 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(); @@ -2027,8 +2032,10 @@ static int elf_core_dump(struct coredump_params *cprm) * Collect all the non-memory information about the process for the * notes. This also sets up the file header. */ - if (!fill_note_info(&elf, e_phnum, &info, cprm)) + if (!fill_note_info(&elf, e_phnum, &info, cprm)) { + coredump_report_failure("Error collecting note info"); goto end_coredump; + } has_dumped = 1; @@ -2043,8 +2050,10 @@ static int elf_core_dump(struct coredump_params *cprm) sz += elf_coredump_extra_notes_size(); phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL); - if (!phdr4note) + if (!phdr4note) { + coredump_report_failure("Error allocating program headers note entry"); goto end_coredump; + } fill_elf_note_phdr(phdr4note, sz, offset); offset += sz; @@ -2058,18 +2067,24 @@ static int elf_core_dump(struct coredump_params *cprm) if (e_phnum == PN_XNUM) { shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL); - if (!shdr4extnum) + if (!shdr4extnum) { + coredump_report_failure("Error allocating extra program headers"); goto end_coredump; + } fill_extnum_info(&elf, shdr4extnum, e_shoff, segs); } offset = dataoff; - if (!dump_emit(cprm, &elf, sizeof(elf))) + if (!dump_emit(cprm, &elf, sizeof(elf))) { + coredump_report_failure("Error emitting the ELF headers"); goto end_coredump; + } - if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note))) + if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note))) { + coredump_report_failure("Error emitting the program header for notes"); goto end_coredump; + } /* Write program headers for segments dump */ for (i = 0; i < cprm->vma_count; i++) { @@ -2092,20 +2107,28 @@ static int elf_core_dump(struct coredump_params *cprm) phdr.p_flags |= PF_X; phdr.p_align = ELF_EXEC_PAGESIZE; - if (!dump_emit(cprm, &phdr, sizeof(phdr))) + if (!dump_emit(cprm, &phdr, sizeof(phdr))) { + coredump_report_failure("Error emitting program headers"); goto end_coredump; + } } - if (!elf_core_write_extra_phdrs(cprm, offset)) + if (!elf_core_write_extra_phdrs(cprm, offset)) { + coredump_report_failure("Error writing out extra program headers"); goto end_coredump; + } /* write out the notes section */ - if (!write_note_info(&info, cprm)) + if (!write_note_info(&info, cprm)) { + coredump_report_failure("Error writing out notes"); goto end_coredump; + } /* For cell spufs and x86 xstate */ - if (elf_coredump_extra_notes_write(cprm)) + if (elf_coredump_extra_notes_write(cprm)) { + coredump_report_failure("Error writing out extra notes"); goto end_coredump; + } /* Align to page */ dump_skip_to(cprm, dataoff); @@ -2113,16 +2136,22 @@ static int elf_core_dump(struct coredump_params *cprm) for (i = 0; i < cprm->vma_count; i++) { struct core_vma_metadata *meta = cprm->vma_meta + i; - if (!dump_user_range(cprm, meta->start, meta->dump_size)) + if (!dump_user_range(cprm, meta->start, meta->dump_size)) { + coredump_report_failure("Error writing out the process memory"); goto end_coredump; + } } - if (!elf_core_write_extra_data(cprm)) + if (!elf_core_write_extra_data(cprm)) { + coredump_report_failure("Error writing out extra data"); goto end_coredump; + } if (e_phnum == PN_XNUM) { - if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum))) + if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum))) { + coredump_report_failure("Error emitting extra program headers"); goto end_coredump; + } } end_coredump: diff --git a/fs/coredump.c b/fs/coredump.c index 7f12ff6ad1d3..53a78b6bbb5b 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -464,7 +465,17 @@ static bool dump_interrupted(void) * but then we need to teach dump_write() to restart and clear * TIF_SIGPENDING. */ - return fatal_signal_pending(current) || freezing(current); + if (fatal_signal_pending(current)) { + coredump_report_failure("interrupted: fatal signal pending"); + return true; + } + + if (freezing(current)) { + coredump_report_failure("interrupted: freezing"); + return true; + } + + return false; } static void wait_for_dump_helpers(struct file *file) @@ -519,7 +530,7 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) return err; } -void do_coredump(const kernel_siginfo_t *siginfo) +int do_coredump(const kernel_siginfo_t *siginfo) { struct core_state core_state; struct core_name cn; @@ -527,7 +538,7 @@ void do_coredump(const kernel_siginfo_t *siginfo) struct linux_binfmt * binfmt; const struct cred *old_cred; struct cred *cred; - int retval = 0; + int retval; int ispipe; size_t *argv = NULL; int argc = 0; @@ -551,14 +562,20 @@ void do_coredump(const kernel_siginfo_t *siginfo) audit_core_dumps(siginfo->si_signo); binfmt = mm->binfmt; - if (!binfmt || !binfmt->core_dump) + if (!binfmt || !binfmt->core_dump) { + retval = -ENOEXEC; goto fail; - if (!__get_dumpable(cprm.mm_flags)) + } + if (!__get_dumpable(cprm.mm_flags)) { + retval = -EACCES; goto fail; + } cred = prepare_creds(); - if (!cred) + if (!cred) { + retval = -EPERM; goto fail; + } /* * We cannot trust fsuid as being the "true" uid of the process * nor do we know its entire history. We only know it was tainted @@ -586,8 +603,8 @@ void do_coredump(const kernel_siginfo_t *siginfo) struct subprocess_info *sub_info; if (ispipe < 0) { - printk(KERN_WARNING "format_corename failed\n"); - printk(KERN_WARNING "Aborting core\n"); + coredump_report_failure("format_corename failed, aborting core"); + retval = ispipe; goto fail_unlock; } @@ -607,27 +624,24 @@ void do_coredump(const kernel_siginfo_t *siginfo) * right pid if a thread in a multi-threaded * core_pattern process dies. */ - printk(KERN_WARNING - "Process %d(%s) has RLIMIT_CORE set to 1\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Aborting core\n"); + coredump_report_failure("RLIMIT_CORE is set to 1, aborting core"); + retval = -EPERM; goto fail_unlock; } cprm.limit = RLIM_INFINITY; dump_count = atomic_inc_return(&core_dump_count); if (core_pipe_limit && (core_pipe_limit < dump_count)) { - printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Skipping core dump\n"); + coredump_report_failure("over core_pipe_limit, skipping core dump"); + retval = -E2BIG; goto fail_dropcount; } helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv), GFP_KERNEL); if (!helper_argv) { - printk(KERN_WARNING "%s failed to allocate memory\n", - __func__); + coredump_report_failure("%s failed to allocate memory", __func__); + retval = -ENOMEM; goto fail_dropcount; } for (argi = 0; argi < argc; argi++) @@ -644,8 +658,7 @@ void do_coredump(const kernel_siginfo_t *siginfo) kfree(helper_argv); if (retval) { - printk(KERN_INFO "Core dump to |%s pipe failed\n", - cn.corename); + coredump_report_failure("|%s pipe failed", cn.corename); goto close_fail; } } else { @@ -654,14 +667,16 @@ void do_coredump(const kernel_siginfo_t *siginfo) int open_flags = O_CREAT | O_WRONLY | O_NOFOLLOW | O_LARGEFILE | O_EXCL; - if (cprm.limit < binfmt->min_coredump) + if (cprm.limit < binfmt->min_coredump) { + coredump_report_failure("over coredump resource limit, skipping core dump"); + retval = -E2BIG; goto fail_unlock; + } if (need_suid_safe && cn.corename[0] != '/') { - printk(KERN_WARNING "Pid %d(%s) can only dump core "\ - "to fully qualified path!\n", - task_tgid_vnr(current), current->comm); - printk(KERN_WARNING "Skipping core dump\n"); + coredump_report_failure( + "this process can only dump core to a fully qualified path, skipping core dump"); + retval = -EPERM; goto fail_unlock; } @@ -707,20 +722,28 @@ void do_coredump(const kernel_siginfo_t *siginfo) } else { cprm.file = filp_open(cn.corename, open_flags, 0600); } - if (IS_ERR(cprm.file)) + if (IS_ERR(cprm.file)) { + retval = PTR_ERR(cprm.file); goto fail_unlock; + } inode = file_inode(cprm.file); - if (inode->i_nlink > 1) + if (inode->i_nlink > 1) { + retval = -EMLINK; goto close_fail; - if (d_unhashed(cprm.file->f_path.dentry)) + } + if (d_unhashed(cprm.file->f_path.dentry)) { + retval = -EEXIST; goto close_fail; + } /* * AK: actually i see no reason to not allow this for named * pipes etc, but keep the previous behaviour for now. */ - if (!S_ISREG(inode->i_mode)) + if (!S_ISREG(inode->i_mode)) { + retval = -EISDIR; goto close_fail; + } /* * Don't dump core if the filesystem changed owner or mode * of the file during file creation. This is an issue when @@ -730,19 +753,24 @@ void do_coredump(const kernel_siginfo_t *siginfo) idmap = file_mnt_idmap(cprm.file); if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode), current_fsuid())) { - pr_info_ratelimited("Core dump to %s aborted: cannot preserve file owner\n", - cn.corename); + coredump_report_failure("Core dump to %s aborted: " + "cannot preserve file owner", cn.corename); + retval = -EPERM; goto close_fail; } if ((inode->i_mode & 0677) != 0600) { - pr_info_ratelimited("Core dump to %s aborted: cannot preserve file permissions\n", - cn.corename); + coredump_report_failure("Core dump to %s aborted: " + "cannot preserve file permissions", cn.corename); + retval = -EPERM; goto close_fail; } - if (!(cprm.file->f_mode & FMODE_CAN_WRITE)) + if (!(cprm.file->f_mode & FMODE_CAN_WRITE)) { + retval = -EACCES; goto close_fail; - if (do_truncate(idmap, cprm.file->f_path.dentry, - 0, 0, cprm.file)) + } + retval = do_truncate(idmap, cprm.file->f_path.dentry, + 0, 0, cprm.file); + if (retval) goto close_fail; } @@ -757,11 +785,16 @@ void do_coredump(const kernel_siginfo_t *siginfo) * have this set to NULL. */ if (!cprm.file) { - pr_info("Core dump to |%s disabled\n", cn.corename); + coredump_report_failure("Core dump to |%s disabled", cn.corename); + retval = -EPERM; goto close_fail; } - if (!dump_vma_snapshot(&cprm)) + if (!dump_vma_snapshot(&cprm)) { + coredump_report_failure("Can't get VMA snapshot for core dump |%s", + cn.corename); + retval = -EACCES; goto close_fail; + } file_start_write(cprm.file); core_dumped = binfmt->core_dump(&cprm); @@ -777,9 +810,21 @@ void do_coredump(const kernel_siginfo_t *siginfo) } file_end_write(cprm.file); free_vma_snapshot(&cprm); + } else { + coredump_report_failure("Core dump to %s%s has been interrupted", + ispipe ? "|" : "", cn.corename); + retval = -EAGAIN; + goto fail; } + coredump_report( + "written to %s%s: VMAs: %d, size %zu; core: %lld bytes, pos %lld", + ispipe ? "|" : "", cn.corename, + cprm.vma_count, cprm.vma_data_size, cprm.written, cprm.pos); if (ispipe && core_pipe_limit) wait_for_dump_helpers(cprm.file); + + retval = 0; + close_fail: if (cprm.file) filp_close(cprm.file, NULL); @@ -794,7 +839,7 @@ fail_unlock: fail_creds: put_cred(cred); fail: - return; + return retval; } /* @@ -814,8 +859,16 @@ static int __dump_emit(struct coredump_params *cprm, const void *addr, int nr) if (dump_interrupted()) return 0; n = __kernel_write(file, addr, nr, &pos); - if (n != nr) + if (n != nr) { + if (n < 0) + coredump_report_failure("failed when writing out, error %zd", n); + else + coredump_report_failure( + "partially written out, only %zd(of %d) bytes written", + n, nr); + return 0; + } file->f_pos = pos; cprm->written += n; cprm->pos += n; @@ -828,9 +881,16 @@ static int __dump_skip(struct coredump_params *cprm, size_t nr) static char zeroes[PAGE_SIZE]; struct file *file = cprm->file; if (file->f_mode & FMODE_LSEEK) { - if (dump_interrupted() || - vfs_llseek(file, nr, SEEK_CUR) < 0) + int ret; + + if (dump_interrupted()) return 0; + + ret = vfs_llseek(file, nr, SEEK_CUR); + if (ret < 0) { + coredump_report_failure("failed when seeking, error %d", ret); + return 0; + } cprm->pos += nr; return 1; } else { @@ -983,11 +1043,10 @@ void validate_coredump_safety(void) { if (suid_dumpable == SUID_DUMP_ROOT && core_pattern[0] != '/' && core_pattern[0] != '|') { - pr_warn( -"Unsafe core_pattern used with fs.suid_dumpable=2.\n" -"Pipe handler or fully qualified core dump path required.\n" -"Set kernel.core_pattern before fs.suid_dumpable.\n" - ); + + coredump_report_failure("Unsafe core_pattern used with fs.suid_dumpable=2: " + "pipe handler or fully qualified core dump path required. " + "Set kernel.core_pattern before fs.suid_dumpable."); } } @@ -1191,6 +1250,18 @@ static void free_vma_snapshot(struct coredump_params *cprm) } } +static int cmp_vma_size(const void *vma_meta_lhs_ptr, const void *vma_meta_rhs_ptr) +{ + const struct core_vma_metadata *vma_meta_lhs = vma_meta_lhs_ptr; + const struct core_vma_metadata *vma_meta_rhs = vma_meta_rhs_ptr; + + if (vma_meta_lhs->dump_size < vma_meta_rhs->dump_size) + return -1; + if (vma_meta_lhs->dump_size > vma_meta_rhs->dump_size) + return 1; + return 0; +} + /* * Under the mmap_lock, take a snapshot of relevant information about the task's * VMAs. @@ -1253,5 +1324,8 @@ static bool dump_vma_snapshot(struct coredump_params *cprm) cprm->vma_data_size += m->dump_size; } + sort(cprm->vma_meta, cprm->vma_count, sizeof(*cprm->vma_meta), + cmp_vma_size, NULL); + return true; } diff --git a/include/linux/coredump.h b/include/linux/coredump.h index 0904ba010341..edeb8532ce0f 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -42,9 +42,35 @@ extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr); extern int dump_align(struct coredump_params *cprm, int align); int dump_user_range(struct coredump_params *cprm, unsigned long start, unsigned long len); -extern void do_coredump(const kernel_siginfo_t *siginfo); +extern int do_coredump(const kernel_siginfo_t *siginfo); + +/* + * Logging for the coredump code, ratelimited. + * The TGID and comm fields are added to the message. + */ + +#define __COREDUMP_PRINTK(Level, Format, ...) \ + do { \ + char comm[TASK_COMM_LEN]; \ + \ + get_task_comm(comm, current); \ + printk_ratelimited(Level "coredump: %d(%*pE): " Format "\n", \ + task_tgid_vnr(current), (int)strlen(comm), comm, ##__VA_ARGS__); \ + } while (0) \ + +#define coredump_report(fmt, ...) __COREDUMP_PRINTK(KERN_INFO, fmt, ##__VA_ARGS__) +#define coredump_report_failure(fmt, ...) __COREDUMP_PRINTK(KERN_WARNING, fmt, ##__VA_ARGS__) + #else -static inline void do_coredump(const kernel_siginfo_t *siginfo) {} +static inline int do_coredump(const kernel_siginfo_t *siginfo) +{ + /* Coredump support is not available, can't fail. */ + return 0; +} + +#define coredump_report(...) +#define coredump_report_failure(...) + #endif #if defined(CONFIG_COREDUMP) && defined(CONFIG_SYSCTL) diff --git a/include/linux/mm.h b/include/linux/mm.h index 3066af38e94e..5be52b7ac573 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4221,4 +4221,14 @@ void vma_pgtable_walk_end(struct vm_area_struct *vma); int reserve_mem_find_by_name(const char *name, phys_addr_t *start, phys_addr_t *size); +#ifdef CONFIG_64BIT +int do_mseal(unsigned long start, size_t len_in, unsigned long flags); +#else +static inline int do_mseal(unsigned long start, size_t len_in, unsigned long flags) +{ + /* noop on 32 bit */ + return 0; +} +#endif + #endif /* _LINUX_MM_H */ diff --git a/kernel/signal.c b/kernel/signal.c index 6f3a5aa39b09..6fe29715105b 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2888,6 +2888,8 @@ relock: current->flags |= PF_SIGNALED; if (sig_kernel_coredump(signr)) { + int ret; + if (print_fatal_signals) print_fatal_signal(signr); proc_coredump_connector(current); @@ -2899,7 +2901,24 @@ relock: * first and our do_group_exit call below will use * that value and ignore the one we pass it. */ - do_coredump(&ksig->info); + ret = do_coredump(&ksig->info); + if (ret) + coredump_report_failure("coredump has not been created, error %d", + ret); + else if (!IS_ENABLED(CONFIG_COREDUMP)) { + /* + * Coredumps are not available, can't fail collecting + * the coredump. + * + * Leave a note though that the coredump is going to be + * not created. This is not an error or a warning as disabling + * support in the kernel for coredumps isn't commonplace, and + * the user must've built the kernel with the custom config so + * let them know all works as desired. + */ + coredump_report("no coredump collected as " + "that is disabled in the kernel configuration"); + } } /* diff --git a/mm/mseal.c b/mm/mseal.c index 15bba28acc00..c8787cc6ba55 100644 --- a/mm/mseal.c +++ b/mm/mseal.c @@ -256,7 +256,7 @@ static int apply_mm_seal(unsigned long start, unsigned long end) * * unseal() is not supported. */ -static int do_mseal(unsigned long start, size_t len_in, unsigned long flags) +int do_mseal(unsigned long start, size_t len_in, unsigned long flags) { size_t len; int ret = 0;