From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46960) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6ebM-00019q-M3 for qemu-devel@nongnu.org; Tue, 06 Aug 2013 06:34:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V6ebH-0003rk-KB for qemu-devel@nongnu.org; Tue, 06 Aug 2013 06:34:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26657) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V6ebH-0003rc-Cm for qemu-devel@nongnu.org; Tue, 06 Aug 2013 06:34:47 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r76AYkON026336 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 6 Aug 2013 06:34:46 -0400 From: Laszlo Ersek Date: Tue, 6 Aug 2013 12:37:08 +0200 Message-Id: <1375785431-8390-2-git-send-email-lersek@redhat.com> In-Reply-To: <1375785431-8390-1-git-send-email-lersek@redhat.com> References: <1375785431-8390-1-git-send-email-lersek@redhat.com> Subject: [Qemu-devel] [PATCH v3 for-qmp-1.6 1/4] dump: clamp guest-provided mapping lengths to ramblock sizes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, pbonzini@redhat.com, lcapitulino@redhat.com Even a trusted & clean-state guest can map more memory than what it was given. Since the vmcore contains RAMBlocks, mapping sizes should be clamped to RAMBlock sizes. Otherwise such oversized mappings can exceed the entire file size, and ELF parsers might refuse even the valid portion of the PT_LOAD entry. Related RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=981582 Signed-off-by: Laszlo Ersek --- dump.c | 65 +++++++++++++++++++++++++++++++++++++++------------------------ 1 files changed, 40 insertions(+), 25 deletions(-) diff --git a/dump.c b/dump.c index 6a3a72a..9a2f939 100644 --- a/dump.c +++ b/dump.c @@ -187,7 +187,8 @@ static int write_elf32_header(DumpState *s) } static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping, - int phdr_index, hwaddr offset) + int phdr_index, hwaddr offset, + hwaddr filesz) { Elf64_Phdr phdr; int ret; @@ -197,15 +198,12 @@ static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping, phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian); phdr.p_offset = cpu_convert_to_target64(offset, endian); phdr.p_paddr = cpu_convert_to_target64(memory_mapping->phys_addr, endian); - if (offset == -1) { - /* When the memory is not stored into vmcore, offset will be -1 */ - phdr.p_filesz = 0; - } else { - phdr.p_filesz = cpu_convert_to_target64(memory_mapping->length, endian); - } + phdr.p_filesz = cpu_convert_to_target64(filesz, endian); phdr.p_memsz = cpu_convert_to_target64(memory_mapping->length, endian); phdr.p_vaddr = cpu_convert_to_target64(memory_mapping->virt_addr, endian); + assert(memory_mapping->length >= filesz); + ret = fd_write_vmcore(&phdr, sizeof(Elf64_Phdr), s); if (ret < 0) { dump_error(s, "dump: failed to write program header table.\n"); @@ -216,7 +214,8 @@ static int write_elf64_load(DumpState *s, MemoryMapping *memory_mapping, } static int write_elf32_load(DumpState *s, MemoryMapping *memory_mapping, - int phdr_index, hwaddr offset) + int phdr_index, hwaddr offset, + hwaddr filesz) { Elf32_Phdr phdr; int ret; @@ -226,15 +225,12 @@ static int write_elf32_load(DumpState *s, MemoryMapping *memory_mapping, phdr.p_type = cpu_convert_to_target32(PT_LOAD, endian); phdr.p_offset = cpu_convert_to_target32(offset, endian); phdr.p_paddr = cpu_convert_to_target32(memory_mapping->phys_addr, endian); - if (offset == -1) { - /* When the memory is not stored into vmcore, offset will be -1 */ - phdr.p_filesz = 0; - } else { - phdr.p_filesz = cpu_convert_to_target32(memory_mapping->length, endian); - } + phdr.p_filesz = cpu_convert_to_target32(filesz, endian); phdr.p_memsz = cpu_convert_to_target32(memory_mapping->length, endian); phdr.p_vaddr = cpu_convert_to_target32(memory_mapping->virt_addr, endian); + assert(memory_mapping->length >= filesz); + ret = fd_write_vmcore(&phdr, sizeof(Elf32_Phdr), s); if (ret < 0) { dump_error(s, "dump: failed to write program header table.\n"); @@ -418,17 +414,24 @@ static int write_memory(DumpState *s, RAMBlock *block, ram_addr_t start, return 0; } -/* get the memory's offset in the vmcore */ -static hwaddr get_offset(hwaddr phys_addr, - DumpState *s) +/* get the memory's offset and size in the vmcore */ +static void get_offset_range(hwaddr phys_addr, + ram_addr_t mapping_length, + DumpState *s, + hwaddr *p_offset, + hwaddr *p_filesz) { RAMBlock *block; hwaddr offset = s->memory_offset; int64_t size_in_block, start; + /* When the memory is not stored into vmcore, offset will be -1 */ + *p_offset = -1; + *p_filesz = 0; + if (s->has_filter) { if (phys_addr < s->begin || phys_addr >= s->begin + s->length) { - return -1; + return; } } @@ -457,18 +460,26 @@ static hwaddr get_offset(hwaddr phys_addr, } if (phys_addr >= start && phys_addr < start + size_in_block) { - return phys_addr - start + offset; + *p_offset = phys_addr - start + offset; + + /* The offset range mapped from the vmcore file must not spill over + * the RAMBlock, clamp it. The rest of the mapping will be + * zero-filled in memory at load time; see + * . + */ + *p_filesz = phys_addr + mapping_length <= start + size_in_block ? + mapping_length : + size_in_block - (phys_addr - start); + return; } offset += size_in_block; } - - return -1; } static int write_elf_loads(DumpState *s) { - hwaddr offset; + hwaddr offset, filesz; MemoryMapping *memory_mapping; uint32_t phdr_index = 1; int ret; @@ -481,11 +492,15 @@ static int write_elf_loads(DumpState *s) } QTAILQ_FOREACH(memory_mapping, &s->list.head, next) { - offset = get_offset(memory_mapping->phys_addr, s); + get_offset_range(memory_mapping->phys_addr, + memory_mapping->length, + s, &offset, &filesz); if (s->dump_info.d_class == ELFCLASS64) { - ret = write_elf64_load(s, memory_mapping, phdr_index++, offset); + ret = write_elf64_load(s, memory_mapping, phdr_index++, offset, + filesz); } else { - ret = write_elf32_load(s, memory_mapping, phdr_index++, offset); + ret = write_elf32_load(s, memory_mapping, phdr_index++, offset, + filesz); } if (ret < 0) { -- 1.7.1