Revision fdad35ef6c5839d50dfc14073364ac893afebc30 authored by Eric Blake on 22 November 2017, 22:25:16 UTC, committed by Eric Blake on 28 November 2017, 12:42:26 UTC
The NBD spec gives us permission to abruptly disconnect on clients that send outrageously large option requests, rather than having to spend the time reading to the end of the option. No real option request requires that much data anyways; and meanwhile, we already have the practice of abruptly dropping the connection on any client that sends NBD_CMD_WRITE with a payload larger than 32M. For comparison, nbdkit drops the connection on any request with more than 4096 bytes; however, that limit is probably too low (as the NBD spec states an export name can theoretically be up to 4096 bytes, which means a valid NBD_OPT_INFO could be even longer) - even if qemu doesn't permit exports longer than 256 bytes. It could be argued that a malicious client trying to get us to read nearly 4G of data on a bad request is a form of denial of service. In particular, if the server requires TLS, but a client that does not know the TLS credentials sends any option (other than NBD_OPT_STARTTLS or NBD_OPT_EXPORT_NAME) with a stated payload of nearly 4G, then the server was keeping the connection alive trying to read all the payload, tying up resources that it would rather be spending on a client that can get past the TLS handshake. Hence, this warranted a CVE. Present since at least 2.5 when handling known options, and made worse in 2.6 when fixing support for NBD_FLAG_C_FIXED_NEWSTYLE to handle unknown options. CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake <eblake@redhat.com>
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cpu-all.h
/*
* defines common to all virtual CPUs
*
* Copyright (c) 2003 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#ifndef CPU_ALL_H
#define CPU_ALL_H
#include "qemu-common.h"
#include "exec/cpu-common.h"
#include "exec/memory.h"
#include "qemu/thread.h"
#include "qom/cpu.h"
#include "qemu/rcu.h"
#define EXCP_INTERRUPT 0x10000 /* async interruption */
#define EXCP_HLT 0x10001 /* hlt instruction reached */
#define EXCP_DEBUG 0x10002 /* cpu stopped after a breakpoint or singlestep */
#define EXCP_HALTED 0x10003 /* cpu is halted (waiting for external event) */
#define EXCP_YIELD 0x10004 /* cpu wants to yield timeslice to another */
#define EXCP_ATOMIC 0x10005 /* stop-the-world and emulate atomic */
/* some important defines:
*
* HOST_WORDS_BIGENDIAN : if defined, the host cpu is big endian and
* otherwise little endian.
*
* TARGET_WORDS_BIGENDIAN : same for target cpu
*/
#if defined(HOST_WORDS_BIGENDIAN) != defined(TARGET_WORDS_BIGENDIAN)
#define BSWAP_NEEDED
#endif
#ifdef BSWAP_NEEDED
static inline uint16_t tswap16(uint16_t s)
{
return bswap16(s);
}
static inline uint32_t tswap32(uint32_t s)
{
return bswap32(s);
}
static inline uint64_t tswap64(uint64_t s)
{
return bswap64(s);
}
static inline void tswap16s(uint16_t *s)
{
*s = bswap16(*s);
}
static inline void tswap32s(uint32_t *s)
{
*s = bswap32(*s);
}
static inline void tswap64s(uint64_t *s)
{
*s = bswap64(*s);
}
#else
static inline uint16_t tswap16(uint16_t s)
{
return s;
}
static inline uint32_t tswap32(uint32_t s)
{
return s;
}
static inline uint64_t tswap64(uint64_t s)
{
return s;
}
static inline void tswap16s(uint16_t *s)
{
}
static inline void tswap32s(uint32_t *s)
{
}
static inline void tswap64s(uint64_t *s)
{
}
#endif
#if TARGET_LONG_SIZE == 4
#define tswapl(s) tswap32(s)
#define tswapls(s) tswap32s((uint32_t *)(s))
#define bswaptls(s) bswap32s(s)
#else
#define tswapl(s) tswap64(s)
#define tswapls(s) tswap64s((uint64_t *)(s))
#define bswaptls(s) bswap64s(s)
#endif
/* Target-endianness CPU memory access functions. These fit into the
* {ld,st}{type}{sign}{size}{endian}_p naming scheme described in bswap.h.
*/
#if defined(TARGET_WORDS_BIGENDIAN)
#define lduw_p(p) lduw_be_p(p)
#define ldsw_p(p) ldsw_be_p(p)
#define ldl_p(p) ldl_be_p(p)
#define ldq_p(p) ldq_be_p(p)
#define ldfl_p(p) ldfl_be_p(p)
#define ldfq_p(p) ldfq_be_p(p)
#define stw_p(p, v) stw_be_p(p, v)
#define stl_p(p, v) stl_be_p(p, v)
#define stq_p(p, v) stq_be_p(p, v)
#define stfl_p(p, v) stfl_be_p(p, v)
#define stfq_p(p, v) stfq_be_p(p, v)
#else
#define lduw_p(p) lduw_le_p(p)
#define ldsw_p(p) ldsw_le_p(p)
#define ldl_p(p) ldl_le_p(p)
#define ldq_p(p) ldq_le_p(p)
#define ldfl_p(p) ldfl_le_p(p)
#define ldfq_p(p) ldfq_le_p(p)
#define stw_p(p, v) stw_le_p(p, v)
#define stl_p(p, v) stl_le_p(p, v)
#define stq_p(p, v) stq_le_p(p, v)
#define stfl_p(p, v) stfl_le_p(p, v)
#define stfq_p(p, v) stfq_le_p(p, v)
#endif
/* MMU memory access macros */
#if defined(CONFIG_USER_ONLY)
#include "exec/user/abitypes.h"
/* On some host systems the guest address space is reserved on the host.
* This allows the guest address space to be offset to a convenient location.
*/
extern unsigned long guest_base;
extern int have_guest_base;
extern unsigned long reserved_va;
#define GUEST_ADDR_MAX (reserved_va ? reserved_va : \
(1ul << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
#else
#include "exec/hwaddr.h"
uint32_t lduw_phys(AddressSpace *as, hwaddr addr);
uint32_t ldl_phys(AddressSpace *as, hwaddr addr);
uint64_t ldq_phys(AddressSpace *as, hwaddr addr);
void stl_phys_notdirty(AddressSpace *as, hwaddr addr, uint32_t val);
void stw_phys(AddressSpace *as, hwaddr addr, uint32_t val);
void stl_phys(AddressSpace *as, hwaddr addr, uint32_t val);
void stq_phys(AddressSpace *as, hwaddr addr, uint64_t val);
uint32_t address_space_lduw(AddressSpace *as, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint32_t address_space_ldl(AddressSpace *as, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint64_t address_space_ldq(AddressSpace *as, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl_notdirty(AddressSpace *as, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stw(AddressSpace *as, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl(AddressSpace *as, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stq(AddressSpace *as, hwaddr addr, uint64_t val,
MemTxAttrs attrs, MemTxResult *result);
uint32_t lduw_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint32_t ldl_phys_cached(MemoryRegionCache *cache, hwaddr addr);
uint64_t ldq_phys_cached(MemoryRegionCache *cache, hwaddr addr);
void stl_phys_notdirty_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stw_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stl_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val);
void stq_phys_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val);
uint32_t address_space_lduw_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint32_t address_space_ldl_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
uint64_t address_space_ldq_cached(MemoryRegionCache *cache, hwaddr addr,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl_notdirty_cached(MemoryRegionCache *cache, hwaddr addr,
uint32_t val, MemTxAttrs attrs, MemTxResult *result);
void address_space_stw_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stl_cached(MemoryRegionCache *cache, hwaddr addr, uint32_t val,
MemTxAttrs attrs, MemTxResult *result);
void address_space_stq_cached(MemoryRegionCache *cache, hwaddr addr, uint64_t val,
MemTxAttrs attrs, MemTxResult *result);
#endif
/* page related stuff */
#ifdef TARGET_PAGE_BITS_VARY
extern bool target_page_bits_decided;
extern int target_page_bits;
#define TARGET_PAGE_BITS ({ assert(target_page_bits_decided); \
target_page_bits; })
#else
#define TARGET_PAGE_BITS_MIN TARGET_PAGE_BITS
#endif
#define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS)
#define TARGET_PAGE_MASK ~(TARGET_PAGE_SIZE - 1)
#define TARGET_PAGE_ALIGN(addr) (((addr) + TARGET_PAGE_SIZE - 1) & TARGET_PAGE_MASK)
/* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
* when intptr_t is 32-bit and we are aligning a long long.
*/
extern uintptr_t qemu_host_page_size;
extern intptr_t qemu_host_page_mask;
#define HOST_PAGE_ALIGN(addr) (((addr) + qemu_host_page_size - 1) & qemu_host_page_mask)
#define REAL_HOST_PAGE_ALIGN(addr) (((addr) + qemu_real_host_page_size - 1) & \
qemu_real_host_page_mask)
/* same as PROT_xxx */
#define PAGE_READ 0x0001
#define PAGE_WRITE 0x0002
#define PAGE_EXEC 0x0004
#define PAGE_BITS (PAGE_READ | PAGE_WRITE | PAGE_EXEC)
#define PAGE_VALID 0x0008
/* original state of the write flag (used when tracking self-modifying
code */
#define PAGE_WRITE_ORG 0x0010
/* Invalidate the TLB entry immediately, helpful for s390x
* Low-Address-Protection. Used with PAGE_WRITE in tlb_set_page_with_attrs() */
#define PAGE_WRITE_INV 0x0040
#if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY)
/* FIXME: Code that sets/uses this is broken and needs to go away. */
#define PAGE_RESERVED 0x0020
#endif
#if defined(CONFIG_USER_ONLY)
void page_dump(FILE *f);
typedef int (*walk_memory_regions_fn)(void *, target_ulong,
target_ulong, unsigned long);
int walk_memory_regions(void *, walk_memory_regions_fn);
int page_get_flags(target_ulong address);
void page_set_flags(target_ulong start, target_ulong end, int flags);
int page_check_range(target_ulong start, target_ulong len, int flags);
#endif
CPUArchState *cpu_copy(CPUArchState *env);
/* Flags for use in ENV->INTERRUPT_PENDING.
The numbers assigned here are non-sequential in order to preserve
binary compatibility with the vmstate dump. Bit 0 (0x0001) was
previously used for CPU_INTERRUPT_EXIT, and is cleared when loading
the vmstate dump. */
/* External hardware interrupt pending. This is typically used for
interrupts from devices. */
#define CPU_INTERRUPT_HARD 0x0002
/* Exit the current TB. This is typically used when some system-level device
makes some change to the memory mapping. E.g. the a20 line change. */
#define CPU_INTERRUPT_EXITTB 0x0004
/* Halt the CPU. */
#define CPU_INTERRUPT_HALT 0x0020
/* Debug event pending. */
#define CPU_INTERRUPT_DEBUG 0x0080
/* Reset signal. */
#define CPU_INTERRUPT_RESET 0x0400
/* Several target-specific external hardware interrupts. Each target/cpu.h
should define proper names based on these defines. */
#define CPU_INTERRUPT_TGT_EXT_0 0x0008
#define CPU_INTERRUPT_TGT_EXT_1 0x0010
#define CPU_INTERRUPT_TGT_EXT_2 0x0040
#define CPU_INTERRUPT_TGT_EXT_3 0x0200
#define CPU_INTERRUPT_TGT_EXT_4 0x1000
/* Several target-specific internal interrupts. These differ from the
preceding target-specific interrupts in that they are intended to
originate from within the cpu itself, typically in response to some
instruction being executed. These, therefore, are not masked while
single-stepping within the debugger. */
#define CPU_INTERRUPT_TGT_INT_0 0x0100
#define CPU_INTERRUPT_TGT_INT_1 0x0800
#define CPU_INTERRUPT_TGT_INT_2 0x2000
/* First unused bit: 0x4000. */
/* The set of all bits that should be masked when single-stepping. */
#define CPU_INTERRUPT_SSTEP_MASK \
(CPU_INTERRUPT_HARD \
| CPU_INTERRUPT_TGT_EXT_0 \
| CPU_INTERRUPT_TGT_EXT_1 \
| CPU_INTERRUPT_TGT_EXT_2 \
| CPU_INTERRUPT_TGT_EXT_3 \
| CPU_INTERRUPT_TGT_EXT_4)
#if !defined(CONFIG_USER_ONLY)
/* Flags stored in the low bits of the TLB virtual address. These are
* defined so that fast path ram access is all zeros.
* The flags all must be between TARGET_PAGE_BITS and
* maximum address alignment bit.
*/
/* Zero if TLB entry is valid. */
#define TLB_INVALID_MASK (1 << (TARGET_PAGE_BITS - 1))
/* Set if TLB entry references a clean RAM page. The iotlb entry will
contain the page physical address. */
#define TLB_NOTDIRTY (1 << (TARGET_PAGE_BITS - 2))
/* Set if TLB entry is an IO callback. */
#define TLB_MMIO (1 << (TARGET_PAGE_BITS - 3))
/* Use this mask to check interception with an alignment mask
* in a TCG backend.
*/
#define TLB_FLAGS_MASK (TLB_INVALID_MASK | TLB_NOTDIRTY | TLB_MMIO)
void dump_exec_info(FILE *f, fprintf_function cpu_fprintf);
void dump_opcount_info(FILE *f, fprintf_function cpu_fprintf);
#endif /* !CONFIG_USER_ONLY */
int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
uint8_t *buf, int len, int is_write);
int cpu_exec(CPUState *cpu);
#endif /* CPU_ALL_H */
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