>From 70b4ac057197f03118168e62089c9d30bc3f8225 Mon Sep 17 00:00:00 2001 Date: Fri, 22 Jun 2007 19:31:02 +0000 Subject: [PATCH] fix vdso in core dumps Taken from RHEL5 kernel source. From: Roland McGrath Subject: [RHEL5 PATCH] fix vdso in core dumps (RHBZ #211744) Date: Sat, 13 Jan 2007 21:49:44 -0800 (PST) Bugzilla: 211744 Message-Id: <20070114054944.D52A61800E5@magilla.sf.frob.com> Changelog: fix vdso in core dumps The problems are inherited from upstream. There used to be corrections for this incorporated into the exec-shield patch when it had a lot of change to the vdso setup; it no longer has to do anything to the vdso code because upstream took similar changes, but broke the core dump part. Note that linux-2.6-execshield.patch has some related cruft from the past that should not be there, and I've excised it from the rawhide version. Thanks, Roland --- arch/i386/kernel/sysenter.c | 12 +++++---- arch/powerpc/kernel/vdso.c | 7 +++++ arch/x86_64/ia32/ia32_binfmt.c | 49 ---------------------------------------- arch/x86_64/ia32/syscall32.c | 7 +++++ fs/binfmt_elf.c | 4 +++ include/asm-i386/elf.h | 44 ----------------------------------- include/linux/mm.h | 1 + 7 files changed, 26 insertions(+), 98 deletions(-) diff --git a/arch/i386/kernel/sysenter.c b/arch/i386/kernel/sysenter.c index 713ba39..fe9f060 100644 --- a/arch/i386/kernel/sysenter.c +++ b/arch/i386/kernel/sysenter.c @@ -75,11 +75,6 @@ int __init sysenter_setup(void) #ifdef CONFIG_COMPAT_VDSO __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_READONLY); printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO)); -#else - /* - * In the non-compat case the ELF coredumping code needs the fixmap: - */ - __set_fixmap(FIX_VDSO, __pa(syscall_page), PAGE_KERNEL_RO); #endif if (!boot_cpu_has(X86_FEATURE_SEP)) { @@ -142,6 +137,13 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack) vma->vm_end = addr + PAGE_SIZE; /* MAYWRITE to allow gdb to COW and set breakpoints */ vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE; + /* + * Make sure the vDSO gets into every core dump. + * Dumping its contents makes post-mortem fully interpretable later + * without matching up the same kernel and hardware config to see + * what PC values meant. + */ + vma->vm_flags |= VM_ALWAYSDUMP; vma->vm_flags |= mm->def_flags; vma->vm_page_prot = protection_map[vma->vm_flags & 7]; vma->vm_ops = &syscall_vm_ops; diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index 1a7e19c..6b2e209 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -282,6 +282,13 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, * pages though */ vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC; + /* + * Make sure the vDSO gets into every core dump. + * Dumping its contents makes post-mortem fully interpretable later + * without matching up the same kernel and hardware config to see + * what PC values meant. + */ + vma->vm_flags |= VM_ALWAYSDUMP; vma->vm_flags |= mm->def_flags; vma->vm_page_prot = protection_map[vma->vm_flags & 0x7]; vma->vm_ops = &vdso_vmops; diff --git a/arch/x86_64/ia32/ia32_binfmt.c b/arch/x86_64/ia32/ia32_binfmt.c index 2fd5a67..6a78b5b 100644 --- a/arch/x86_64/ia32/ia32_binfmt.c +++ b/arch/x86_64/ia32/ia32_binfmt.c @@ -65,55 +65,6 @@ typedef unsigned int elf_greg_t; #define ELF_NGREG (sizeof (struct user_regs_struct32) / sizeof(elf_greg_t)) typedef elf_greg_t elf_gregset_t[ELF_NGREG]; -/* - * These macros parameterize elf_core_dump in fs/binfmt_elf.c to write out - * extra segments containing the vsyscall DSO contents. Dumping its - * contents makes post-mortem fully interpretable later without matching up - * the same kernel and hardware config to see what PC values meant. - * Dumping its extra ELF program headers includes all the other information - * a debugger needs to easily find how the vsyscall DSO was being used. - */ -#define ELF_CORE_EXTRA_PHDRS (find_vma(current->mm, VSYSCALL32_BASE) ? \ - (VSYSCALL32_EHDR->e_phnum) : 0) -#define ELF_CORE_WRITE_EXTRA_PHDRS \ -do { \ - if (find_vma(current->mm, VSYSCALL32_BASE)) { \ - const struct elf32_phdr *const vsyscall_phdrs = \ - (const struct elf32_phdr *) (VSYSCALL32_BASE \ - + VSYSCALL32_EHDR->e_phoff);\ - int i; \ - Elf32_Off ofs = 0; \ - for (i = 0; i < VSYSCALL32_EHDR->e_phnum; ++i) { \ - struct elf32_phdr phdr = vsyscall_phdrs[i]; \ - if (phdr.p_type == PT_LOAD) { \ - BUG_ON(ofs != 0); \ - ofs = phdr.p_offset = offset; \ - phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz); \ - phdr.p_filesz = phdr.p_memsz; \ - offset += phdr.p_filesz; \ - } \ - else \ - phdr.p_offset += ofs; \ - phdr.p_paddr = 0; /* match other core phdrs */ \ - DUMP_WRITE(&phdr, sizeof(phdr)); \ - } \ - } \ -} while (0) -#define ELF_CORE_WRITE_EXTRA_DATA \ -do { \ - if (find_vma(current->mm, VSYSCALL32_BASE)) { \ - const struct elf32_phdr *const vsyscall_phdrs = \ - (const struct elf32_phdr *) (VSYSCALL32_BASE \ - + VSYSCALL32_EHDR->e_phoff); \ - int i; \ - for (i = 0; i < VSYSCALL32_EHDR->e_phnum; ++i) { \ - if (vsyscall_phdrs[i].p_type == PT_LOAD) \ - DUMP_WRITE((void *) (u64) vsyscall_phdrs[i].p_vaddr,\ - PAGE_ALIGN(vsyscall_phdrs[i].p_memsz)); \ - } \ - } \ -} while (0) - struct elf_siginfo { int si_signo; /* signal number */ diff --git a/arch/x86_64/ia32/syscall32.c b/arch/x86_64/ia32/syscall32.c index 3a01329..915d48e 100644 --- a/arch/x86_64/ia32/syscall32.c +++ b/arch/x86_64/ia32/syscall32.c @@ -59,6 +59,13 @@ int syscall32_setup_pages(struct linux_binprm *bprm, int exstack) vma->vm_end = VSYSCALL32_END; /* MAYWRITE to allow gdb to COW and set breakpoints */ vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE; + /* + * Make sure the vDSO gets into every core dump. + * Dumping its contents makes post-mortem fully interpretable later + * without matching up the same kernel and hardware config to see + * what PC values meant. + */ + vma->vm_flags |= VM_ALWAYSDUMP; vma->vm_flags |= mm->def_flags; vma->vm_page_prot = protection_map[vma->vm_flags & 7]; vma->vm_ops = &syscall32_vm_ops; diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 672a3b9..24fbdb8 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1170,6 +1170,10 @@ static int dump_seek(struct file *file, loff_t off) */ static int maydump(struct vm_area_struct *vma) { + /* The vma can be set up to tell us the answer directly. */ + if (vma->vm_flags & VM_ALWAYSDUMP) + return 1; + /* Do not dump I/O mapped devices or special mappings */ if (vma->vm_flags & (VM_IO | VM_RESERVED)) return 0; diff --git a/include/asm-i386/elf.h b/include/asm-i386/elf.h index db4344d..b6e1b6c 100644 --- a/include/asm-i386/elf.h +++ b/include/asm-i386/elf.h @@ -169,50 +169,6 @@ do if (vdso_enabled) { \ NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_COMPAT_BASE); \ } while (0) -/* - * These macros parameterize elf_core_dump in fs/binfmt_elf.c to write out - * extra segments containing the vsyscall DSO contents. Dumping its - * contents makes post-mortem fully interpretable later without matching up - * the same kernel and hardware config to see what PC values meant. - * Dumping its extra ELF program headers includes all the other information - * a debugger needs to easily find how the vsyscall DSO was being used. - */ -#define ELF_CORE_EXTRA_PHDRS (VDSO_HIGH_EHDR->e_phnum) -#define ELF_CORE_WRITE_EXTRA_PHDRS \ -do { \ - const struct elf_phdr *const vsyscall_phdrs = \ - (const struct elf_phdr *) (VDSO_HIGH_BASE \ - + VDSO_HIGH_EHDR->e_phoff); \ - int i; \ - Elf32_Off ofs = 0; \ - for (i = 0; i < VDSO_HIGH_EHDR->e_phnum; ++i) { \ - struct elf_phdr phdr = vsyscall_phdrs[i]; \ - if (phdr.p_type == PT_LOAD) { \ - BUG_ON(ofs != 0); \ - ofs = phdr.p_offset = offset; \ - phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz); \ - phdr.p_filesz = phdr.p_memsz; \ - offset += phdr.p_filesz; \ - } \ - else \ - phdr.p_offset += ofs; \ - phdr.p_paddr = 0; /* match other core phdrs */ \ - DUMP_WRITE(&phdr, sizeof(phdr)); \ - } \ -} while (0) -#define ELF_CORE_WRITE_EXTRA_DATA \ -do { \ - const struct elf_phdr *const vsyscall_phdrs = \ - (const struct elf_phdr *) (VDSO_HIGH_BASE \ - + VDSO_HIGH_EHDR->e_phoff); \ - int i; \ - for (i = 0; i < VDSO_HIGH_EHDR->e_phnum; ++i) { \ - if (vsyscall_phdrs[i].p_type == PT_LOAD) \ - DUMP_WRITE((void *) vsyscall_phdrs[i].p_vaddr, \ - PAGE_ALIGN(vsyscall_phdrs[i].p_memsz)); \ - } \ -} while (0) - #endif #endif diff --git a/include/linux/mm.h b/include/linux/mm.h index f0b135c..6acd011 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -164,6 +164,7 @@ extern unsigned int kobjsize(const void *objp); #define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */ #define VM_MAPPED_COPY 0x01000000 /* T if mapped copy of data (nommu mmap) */ #define VM_INSERTPAGE 0x02000000 /* The vma has had "vm_insert_page()" done on it */ +#define VM_ALWAYSDUMP 0x08000000 /* Always include in core dumps */ #ifndef VM_STACK_DEFAULT_FLAGS /* arch can override this */ #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS -- 1.5.2.1