Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756549Ab3JJPqN (ORCPT ); Thu, 10 Oct 2013 11:46:13 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:52720 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756474Ab3JJPqJ (ORCPT ); Thu, 10 Oct 2013 11:46:09 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Dan Aloni , Al Viro , Denys Vlasenko , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 090/104] fs/binfmt_elf.c: prevent a coredump with a large vm_map_count from Oopsing Date: Thu, 10 Oct 2013 08:42:18 -0700 Message-Id: <1381419752-29733-91-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1381419752-29733-1-git-send-email-kamal@canonical.com> References: <1381419752-29733-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5202 Lines: 148 3.8.13.11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Aloni commit 72023656961b8c81a168a7a6762d589339d0d7ec upstream. A high setting of max_map_count, and a process core-dumping with a large enough vm_map_count could result in an NT_FILE note not being written, and the kernel crashing immediately later because it has assumed otherwise. Reproduction of the oops-causing bug described here: https://lkml.org/lkml/2013/8/30/50 Rge ussue originated in commit 2aa362c49c31 ("coredump: extend core dump note section to contain file names of mapped file") from Oct 4, 2012. This patch make that section optional in that case. fill_files_note() should signify the error, and also let the info struct in elf_core_dump() be zero-initialized so that we can check for the optionally written note. [akpm@linux-foundation.org: avoid abusing E2BIG, remove a couple of not-really-needed local variables] [akpm@linux-foundation.org: fix sparse warning] Signed-off-by: Dan Aloni Cc: Al Viro Cc: Denys Vlasenko Reported-by: Martin MOKREJS Tested-by: Martin MOKREJS Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- fs/binfmt_elf.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 5843a47..0950e59 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1403,7 +1403,7 @@ static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata, * long file_ofs * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL... */ -static void fill_files_note(struct memelfnote *note) +static int fill_files_note(struct memelfnote *note) { struct vm_area_struct *vma; unsigned count, size, names_ofs, remaining, n; @@ -1418,11 +1418,11 @@ static void fill_files_note(struct memelfnote *note) names_ofs = (2 + 3 * count) * sizeof(data[0]); alloc: if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */ - goto err; + return -EINVAL; size = round_up(size, PAGE_SIZE); data = vmalloc(size); if (!data) - goto err; + return -ENOMEM; start_end_ofs = data + 2; name_base = name_curpos = ((char *)data) + names_ofs; @@ -1475,7 +1475,7 @@ static void fill_files_note(struct memelfnote *note) size = name_curpos - (char *)data; fill_note(note, "CORE", NT_FILE, size, data); - err: ; + return 0; } #ifdef CORE_DUMP_USE_REGSET @@ -1676,8 +1676,8 @@ 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); + if (fill_files_note(&info->files) == 0) + info->size += notesize(&info->files); return 1; } @@ -1709,7 +1709,8 @@ 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)) + if (first && info->files.data && + !writenote(&info->files, file, foffset)) return 0; for (i = 1; i < info->thread_notes; ++i) @@ -1796,6 +1797,7 @@ static int elf_dump_thread_status(long signr, struct elf_thread_status *t) struct elf_note_info { struct memelfnote *notes; + struct memelfnote *notes_files; struct elf_prstatus *prstatus; /* NT_PRSTATUS */ struct elf_prpsinfo *psinfo; /* NT_PRPSINFO */ struct list_head thread_list; @@ -1886,9 +1888,12 @@ static int fill_note_info(struct elfhdr *elf, int phdrs, fill_siginfo_note(info->notes + 2, &info->csigdata, siginfo); fill_auxv_note(info->notes + 3, current->mm); - fill_files_note(info->notes + 4); + info->numnote = 4; - info->numnote = 5; + if (fill_files_note(info->notes + info->numnote) == 0) { + info->notes_files = info->notes + info->numnote; + info->numnote++; + } /* Try to dump the FPU. */ info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs, @@ -1950,8 +1955,9 @@ 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); + /* Free data possibly allocated by fill_files_note(): */ + if (info->notes_files) + vfree(info->notes_files->data); kfree(info->prstatus); kfree(info->psinfo); @@ -2034,7 +2040,7 @@ static int elf_core_dump(struct coredump_params *cprm) struct vm_area_struct *vma, *gate_vma; struct elfhdr *elf = NULL; loff_t offset = 0, dataoff, foffset; - struct elf_note_info info; + struct elf_note_info info = { }; struct elf_phdr *phdr4note = NULL; struct elf_shdr *shdr4extnum = NULL; Elf_Half e_phnum; -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/