From ecc8c7725e6c21528329b34acae2a1d64b3af89b Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 5 Oct 2013 15:32:35 -0400 Subject: [PATCH] new helper: dump_emit() dump_write() analog, takes core_dump_params instead of file, keeps track of the amount written in cprm->written and checks for cprm->limit. Start using it in binfmt_elf.c... Signed-off-by: Al Viro --- fs/binfmt_elf.c | 60 +++++++++++++++------------------------- fs/coredump.c | 14 ++++++++++ include/linux/binfmts.h | 1 + include/linux/coredump.h | 2 ++ 4 files changed, 40 insertions(+), 37 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 501c8a4d6eb1..00fd9c969a27 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1225,35 +1225,23 @@ static int notesize(struct memelfnote *en) return sz; } -#define DUMP_WRITE(addr, nr, foffset) \ - do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0) - -static int alignfile(struct file *file, loff_t *foffset) +static int alignfile(struct coredump_params *cprm) { static const char buf[4] = { 0, }; - DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset); - return 1; + return dump_emit(cprm, buf, roundup(cprm->written, 4) - cprm->written); } -static int writenote(struct memelfnote *men, struct file *file, - loff_t *foffset) +static int writenote(struct memelfnote *men, struct coredump_params *cprm) { struct elf_note en; en.n_namesz = strlen(men->name) + 1; en.n_descsz = men->datasz; en.n_type = men->type; - DUMP_WRITE(&en, sizeof(en), foffset); - DUMP_WRITE(men->name, en.n_namesz, foffset); - if (!alignfile(file, foffset)) - return 0; - DUMP_WRITE(men->data, men->datasz, foffset); - if (!alignfile(file, foffset)) - return 0; - - return 1; + return dump_emit(cprm, &en, sizeof(en)) && + dump_emit(cprm, men->name, en.n_namesz) && alignfile(cprm) && + dump_emit(cprm, men->data, men->datasz) && alignfile(cprm); } -#undef DUMP_WRITE static void fill_elf_header(struct elfhdr *elf, int segs, u16 machine, u32 flags) @@ -1702,7 +1690,7 @@ static size_t get_note_info_size(struct elf_note_info *info) * process-wide notes are interleaved after the first thread-specific note. */ static int write_note_info(struct elf_note_info *info, - struct file *file, loff_t *foffset) + struct coredump_params *cprm) { bool first = 1; struct elf_thread_core_info *t = info->thread; @@ -1710,22 +1698,22 @@ static int write_note_info(struct elf_note_info *info, do { int i; - if (!writenote(&t->notes[0], file, foffset)) + if (!writenote(&t->notes[0], cprm)) return 0; - if (first && !writenote(&info->psinfo, file, foffset)) + if (first && !writenote(&info->psinfo, cprm)) return 0; - if (first && !writenote(&info->signote, file, foffset)) + if (first && !writenote(&info->signote, cprm)) return 0; - if (first && !writenote(&info->auxv, file, foffset)) + if (first && !writenote(&info->auxv, cprm)) return 0; if (first && info->files.data && - !writenote(&info->files, file, foffset)) + !writenote(&info->files, cprm)) return 0; for (i = 1; i < info->thread_notes; ++i) if (t->notes[i].data && - !writenote(&t->notes[i], file, foffset)) + !writenote(&t->notes[i], cprm)) return 0; first = 0; @@ -1935,13 +1923,13 @@ static size_t get_note_info_size(struct elf_note_info *info) } static int write_note_info(struct elf_note_info *info, - struct file *file, loff_t *foffset) + struct coredump_params *cprm) { int i; struct list_head *t; for (i = 0; i < info->numnote; i++) - if (!writenote(info->notes + i, file, foffset)) + if (!writenote(info->notes + i, cprm)) return 0; /* write out the thread status notes section */ @@ -1950,7 +1938,7 @@ static int write_note_info(struct elf_note_info *info, list_entry(t, struct elf_thread_status, list); for (i = 0; i < tmp->num_notes; i++) - if (!writenote(&tmp->notes[i], file, foffset)) + if (!writenote(&tmp->notes[i], cprm)) return 0; } @@ -2136,13 +2124,10 @@ static int elf_core_dump(struct coredump_params *cprm) offset = dataoff; - size += sizeof(*elf); - if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf))) + if (!dump_emit(cprm, elf, sizeof(*elf))) goto end_coredump; - size += sizeof(*phdr4note); - if (size > cprm->limit - || !dump_write(cprm->file, phdr4note, sizeof(*phdr4note))) + if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note))) goto end_coredump; /* Write program headers for segments dump */ @@ -2164,19 +2149,20 @@ static int elf_core_dump(struct coredump_params *cprm) phdr.p_flags |= PF_X; phdr.p_align = ELF_EXEC_PAGESIZE; - size += sizeof(phdr); - if (size > cprm->limit - || !dump_write(cprm->file, &phdr, sizeof(phdr))) + if (!dump_emit(cprm, &phdr, sizeof(phdr))) goto end_coredump; } + size = cprm->written; if (!elf_core_write_extra_phdrs(cprm->file, offset, &size, cprm->limit)) goto end_coredump; + cprm->written = foffset; /* will disappear */ /* write out the notes section */ - if (!write_note_info(&info, cprm->file, &foffset)) + if (!write_note_info(&info, cprm)) goto end_coredump; + foffset = cprm->written; if (elf_coredump_extra_notes_write(cprm->file, &foffset)) goto end_coredump; diff --git a/fs/coredump.c b/fs/coredump.c index 42c3b8423669..319f973bab72 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -693,6 +693,20 @@ int dump_write(struct file *file, const void *addr, int nr) } EXPORT_SYMBOL(dump_write); +int dump_emit(struct coredump_params *cprm, const void *addr, int nr) +{ + struct file *file = cprm->file; + if (dump_interrupted() || !access_ok(VERIFY_READ, addr, nr)) + return 0; + if (cprm->written + nr > cprm->limit) + return 0; + if (file->f_op->write(file, addr, nr, &file->f_pos) != nr) + return 0; + cprm->written += nr; + return 1; +} +EXPORT_SYMBOL(dump_emit); + int dump_seek(struct file *file, loff_t off) { int ret = 1; diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index e8112ae50531..8aa507e7a41a 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -61,6 +61,7 @@ struct coredump_params { struct file *file; unsigned long limit; unsigned long mm_flags; + loff_t written; }; /* diff --git a/include/linux/coredump.h b/include/linux/coredump.h index a98f1ca60407..2959376a9ad5 100644 --- a/include/linux/coredump.h +++ b/include/linux/coredump.h @@ -10,8 +10,10 @@ * These are the only things you should do on a core-file: use only these * functions to write out all the necessary info. */ +struct coredump_params; extern int dump_write(struct file *file, const void *addr, int nr); extern int dump_seek(struct file *file, loff_t off); +extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr); #ifdef CONFIG_COREDUMP extern void do_coredump(siginfo_t *siginfo); #else -- 2.20.1