From 49ae4d4b113be03dc4a2ec5f2a1f573ff0fcddb3 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 4 Oct 2012 17:15:35 -0700 Subject: coredump: add a new elf note with siginfo of the signal Existing PRSTATUS note contains only si_signo, si_code, si_errno fields from the siginfo of the signal which caused core to be dumped. There are tools which try to analyze crashes for possible security implications, and they want to use, among other data, si_addr field from the SIGSEGV. This patch adds a new elf note, NT_SIGINFO, which contains the complete siginfo_t of the signal which killed the process. Signed-off-by: Denys Vlasenko Reviewed-by: Oleg Nesterov Cc: Amerigo Wang Cc: "Jonathan M. Foote" Cc: Roland McGrath Cc: Pedro Alves Cc: Fengguang Wu Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/compat_binfmt_elf.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/compat_binfmt_elf.c') diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c index 112e45a17e99..0fbcf6347437 100644 --- a/fs/compat_binfmt_elf.c +++ b/fs/compat_binfmt_elf.c @@ -37,6 +37,12 @@ #define elf_note elf32_note #define elf_addr_t Elf32_Addr +/* + * Some data types as stored in coredump. + */ +#define user_siginfo_t compat_siginfo_t +#define copy_siginfo_to_user copy_siginfo_to_user32 + /* * The machine-dependent core note format types are defined in elfcore-compat.h, * which requires asm/elf.h to define compat_elf_gregset_t et al. -- cgit v1.2.3 From 2aa362c49c314a98fb9aebbd7760a461667bac05 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 4 Oct 2012 17:15:36 -0700 Subject: coredump: extend core dump note section to contain file names of mapped files This note has the following format: long count -- how many files are mapped long page_size -- units for file_ofs array of [COUNT] elements of long start long end long file_ofs followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL... Signed-off-by: Denys Vlasenko Cc: Oleg Nesterov Cc: Amerigo Wang Cc: "Jonathan M. Foote" Cc: Roland McGrath Cc: Pedro Alves Cc: Fengguang Wu Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/binfmt_elf.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++-- fs/compat_binfmt_elf.c | 1 + include/linux/elf.h | 1 + 3 files changed, 108 insertions(+), 4 deletions(-) (limited to 'fs/compat_binfmt_elf.c') diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 865f9be6a2d3..28a64e769527 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -37,6 +38,9 @@ #include #include +#ifndef user_long_t +#define user_long_t long +#endif #ifndef user_siginfo_t #define user_siginfo_t siginfo_t #endif @@ -1386,6 +1390,93 @@ static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata); } +#define MAX_FILE_NOTE_SIZE (4*1024*1024) +/* + * Format of NT_FILE note: + * + * long count -- how many files are mapped + * long page_size -- units for file_ofs + * array of [COUNT] elements of + * long start + * long end + * long file_ofs + * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL... + */ +static void fill_files_note(struct memelfnote *note) +{ + struct vm_area_struct *vma; + unsigned count, size, names_ofs, remaining, n; + user_long_t *data; + user_long_t *start_end_ofs; + char *name_base, *name_curpos; + + /* *Estimated* file count and total data size needed */ + count = current->mm->map_count; + size = count * 64; + + names_ofs = (2 + 3 * count) * sizeof(data[0]); + alloc: + if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */ + goto err; + size = round_up(size, PAGE_SIZE); + data = vmalloc(size); + if (!data) + goto err; + + start_end_ofs = data + 2; + name_base = name_curpos = ((char *)data) + names_ofs; + remaining = size - names_ofs; + count = 0; + for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) { + struct file *file; + const char *filename; + + file = vma->vm_file; + if (!file) + continue; + filename = d_path(&file->f_path, name_curpos, remaining); + if (IS_ERR(filename)) { + if (PTR_ERR(filename) == -ENAMETOOLONG) { + vfree(data); + size = size * 5 / 4; + goto alloc; + } + continue; + } + + /* d_path() fills at the end, move name down */ + /* n = strlen(filename) + 1: */ + n = (name_curpos + remaining) - filename; + remaining = filename - name_curpos; + memmove(name_curpos, filename, n); + name_curpos += n; + + *start_end_ofs++ = vma->vm_start; + *start_end_ofs++ = vma->vm_end; + *start_end_ofs++ = vma->vm_pgoff; + count++; + } + + /* Now we know exact count of files, can store it */ + data[0] = count; + data[1] = PAGE_SIZE; + /* + * Count usually is less than current->mm->map_count, + * we need to move filenames down. + */ + n = current->mm->map_count - count; + if (n != 0) { + unsigned shift_bytes = n * 3 * sizeof(data[0]); + memmove(name_base - shift_bytes, name_base, + name_curpos - name_base); + name_curpos -= shift_bytes; + } + + size = name_curpos - (char *)data; + fill_note(note, "CORE", NT_FILE, size, data); + err: ; +} + #ifdef CORE_DUMP_USE_REGSET #include @@ -1401,6 +1492,7 @@ struct elf_note_info { struct memelfnote psinfo; struct memelfnote signote; struct memelfnote auxv; + struct memelfnote files; user_siginfo_t csigdata; size_t size; int thread_notes; @@ -1581,6 +1673,9 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, fill_auxv_note(&info->auxv, current->mm); info->size += notesize(&info->auxv); + fill_files_note(&info->files); + info->size += notesize(&info->files); + return 1; } @@ -1611,6 +1706,8 @@ static int write_note_info(struct elf_note_info *info, return 0; if (first && !writenote(&info->auxv, file, foffset)) return 0; + if (first && !writenote(&info->files, file, foffset)) + return 0; for (i = 1; i < info->thread_notes; ++i) if (t->notes[i].data && @@ -1637,6 +1734,7 @@ static void free_note_info(struct elf_note_info *info) kfree(t); } kfree(info->psinfo.data); + vfree(info->files.data); } #else @@ -1713,7 +1811,7 @@ static int elf_note_info_init(struct elf_note_info *info) INIT_LIST_HEAD(&info->thread_list); /* Allocate space for ELF notes */ - info->notes = kmalloc(7 * sizeof(struct memelfnote), GFP_KERNEL); + info->notes = kmalloc(8 * sizeof(struct memelfnote), GFP_KERNEL); if (!info->notes) return 0; info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL); @@ -1783,10 +1881,11 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, fill_note(info->notes + 1, "CORE", NT_PRPSINFO, sizeof(*info->psinfo), info->psinfo); - info->numnote = 2; + fill_siginfo_note(info->notes + 2, &info->csigdata, siginfo); + fill_auxv_note(info->notes + 3, current->mm); + fill_files_note(info->notes + 4); - fill_siginfo_note(&info->notes[info->numnote++], &info->csigdata, siginfo); - fill_auxv_note(&info->notes[info->numnote++], current->mm); + info->numnote = 5; /* Try to dump the FPU. */ info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs, @@ -1848,6 +1947,9 @@ static void free_note_info(struct elf_note_info *info) kfree(list_entry(tmp, struct elf_thread_status, list)); } + /* Free data allocated by fill_files_note(): */ + vfree(info->notes[4].data); + kfree(info->prstatus); kfree(info->psinfo); kfree(info->notes); diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c index 0fbcf6347437..a81147e2e4ef 100644 --- a/fs/compat_binfmt_elf.c +++ b/fs/compat_binfmt_elf.c @@ -40,6 +40,7 @@ /* * Some data types as stored in coredump. */ +#define user_long_t compat_long_t #define user_siginfo_t compat_siginfo_t #define copy_siginfo_to_user copy_siginfo_to_user32 diff --git a/include/linux/elf.h b/include/linux/elf.h index dc62da7447ca..59ef40650e1e 100644 --- a/include/linux/elf.h +++ b/include/linux/elf.h @@ -377,6 +377,7 @@ typedef struct elf64_shdr { * in the future to accomodate more fields, don't assume it is fixed! */ #define NT_SIGINFO 0x53494749 +#define NT_FILE 0x46494c45 #define NT_PRXFPREG 0x46e62b7f /* copied from gdb5.1/include/elf/common.h */ #define NT_PPC_VMX 0x100 /* PowerPC Altivec/VMX registers */ #define NT_PPC_SPE 0x101 /* PowerPC SPE/EVR registers */ -- cgit v1.2.3