解決docker使用GDB,無(wú)法進(jìn)入斷點(diǎn)的問(wèn)題

更新時(shí)間：2020年11月18日 09:47:06 作者：mania_yan

這篇文章主要介紹了解決docker使用GDB,無(wú)法進(jìn)入斷點(diǎn)的問(wèn)題，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。一起跟隨小編過(guò)來(lái)看看吧

問(wèn)題

docker里運(yùn)行g(shù)db，打了斷點(diǎn)，卻無(wú)法進(jìn)入斷點(diǎn)

原因

docker為了保證主機(jī)安全，docker開(kāi)了很多安全設(shè)置，其中包括ASLR（Address space layout randomization），即docker里的內(nèi)存地址和主機(jī)內(nèi)存地址是不一樣的。

ASLR會(huì)導(dǎo)致GDB這種依賴地址的程序無(wú)法正常運(yùn)作。

解決方法

使用docker的超級(jí)權(quán)限，加入--privileged(兩個(gè)橫線,markdown語(yǔ)法

如：

docker run --privileged ……

GDB即可正常運(yùn)作

超級(jí)權(quán)限會(huì)關(guān)閉很多安全設(shè)置，可以更充分的使用docker能力

例如，docker里再開(kāi)docker都可以了，呵呵。

補(bǔ)充知識(shí)：docker ptrace: Operation not permitted. 處理方法

docker中g(shù)db在進(jìn)行進(jìn)程debug時(shí)，會(huì)報(bào)錯(cuò)：

(gdb) attach 30721

Attaching to process 30721

ptrace: Operation not permitted.

原因就是因?yàn)閜trace被Docker默認(rèn)禁止的問(wèn)題。考慮到應(yīng)用分析的需要，可以有以下幾種方法解決：

1、關(guān)閉seccomp

docker run --security-opt seccomp=unconfined

2、采用超級(jí)權(quán)限模式

docker run --privileged

3、僅開(kāi)放ptrace限制

docker run --cap-add sys_ptrace

當(dāng)然從安全角度考慮，如只是想使用gdb進(jìn)行debug的話，建議使用第三種。

安全計(jì)算模式（secure computing mode，seccomp）是 Linux 內(nèi)核功能，可以使用它來(lái)限制容器內(nèi)可用的操作。

Docker 的默認(rèn) seccomp 配置文件是一個(gè)白名單，它指定了允許的調(diào)用。

下表列出了由于不在白名單而被有效阻止的重要（但不是全部）系統(tǒng)調(diào)用。該表包含每個(gè)系統(tǒng)調(diào)用被阻止的原因。

Syscall	Description
acct	Accounting syscall which could let containers disable their own resource limits or process accounting. Also gated by CAP_SYS_PACCT.
add_key	Prevent containers from using the kernel keyring, which is not namespaced.
adjtimex	Similar to clock_settime and settimeofday, time/date is not namespaced. Also gated by CAP_SYS_TIME.
bpf	Deny loading potentially persistent bpf programs into kernel, already gated by CAP_SYS_ADMIN.
clock_adjtime	Time/date is not namespaced. Also gated by CAP_SYS_TIME.
clock_settime	Time/date is not namespaced. Also gated by CAP_SYS_TIME.
clone	Deny cloning new namespaces. Also gated by CAP_SYS_ADMIN for CLONE_* flags, except CLONE_USERNS.
create_module	Deny manipulation and functions on kernel modules. Obsolete. Also gated by CAP_SYS_MODULE.
delete_module	Deny manipulation and functions on kernel modules. Also gated by CAP_SYS_MODULE.
finit_module	Deny manipulation and functions on kernel modules. Also gated by CAP_SYS_MODULE.
get_kernel_syms	Deny retrieval of exported kernel and module symbols. Obsolete.
get_mempolicy	Syscall that modifies kernel memory and NUMA settings. Already gated by CAP_SYS_NICE.
init_module	Deny manipulation and functions on kernel modules. Also gated by CAP_SYS_MODULE.
ioperm	Prevent containers from modifying kernel I/O privilege levels. Already gated by CAP_SYS_RAWIO.
iopl	Prevent containers from modifying kernel I/O privilege levels. Already gated by CAP_SYS_RAWIO.
kcmp	Restrict process inspection capabilities, already blocked by dropping CAP_PTRACE.
kexec_file_load	Sister syscall of kexec_load that does the same thing, slightly different arguments. Also gated by CAP_SYS_BOOT.
kexec_load	Deny loading a new kernel for later execution. Also gated by CAP_SYS_BOOT.
keyctl	Prevent containers from using the kernel keyring, which is not namespaced.
lookup_dcookie	Tracing/profiling syscall, which could leak a lot of information on the host. Also gated by CAP_SYS_ADMIN.
mbind	Syscall that modifies kernel memory and NUMA settings. Already gated by CAP_SYS_NICE.
mount	Deny mounting, already gated by CAP_SYS_ADMIN.
move_pages	Syscall that modifies kernel memory and NUMA settings.
name_to_handle_at	Sister syscall to open_by_handle_at. Already gated by CAP_SYS_NICE.
nfsservctl	Deny interaction with the kernel nfs daemon. Obsolete since Linux 3.1.
open_by_handle_at	Cause of an old container breakout. Also gated by CAP_DAC_READ_SEARCH.
perf_event_open	Tracing/profiling syscall, which could leak a lot of information on the host.
personality	Prevent container from enabling BSD emulation. Not inherently dangerous, but poorly tested, potential for a lot of kernel vulns.
pivot_root	Deny pivot_root, should be privileged operation.
process_vm_readv	Restrict process inspection capabilities, already blocked by dropping CAP_PTRACE.
process_vm_writev	Restrict process inspection capabilities, already blocked by dropping CAP_PTRACE.
ptrace	Tracing/profiling syscall, which could leak a lot of information on the host. Already blocked by dropping CAP_PTRACE.
query_module	Deny manipulation and functions on kernel modules. Obsolete.
quotactl	Quota syscall which could let containers disable their own resource limits or process accounting. Also gated by CAP_SYS_ADMIN.
reboot	Don't let containers reboot the host. Also gated by CAP_SYS_BOOT.
request_key	Prevent containers from using the kernel keyring, which is not namespaced.
set_mempolicy	Syscall that modifies kernel memory and NUMA settings. Already gated by CAP_SYS_NICE.
setns	Deny associating a thread with a namespace. Also gated by CAP_SYS_ADMIN.
settimeofday	Time/date is not namespaced. Also gated by CAP_SYS_TIME.
socket, socketcall	Used to send or receive packets and for other socket operations. All socket and socketcall calls are blocked except communication domains AF_UNIX, AF_INET, AF_INET6, AF_NETLINK, and AF_PACKET.
stime	Time/date is not namespaced. Also gated by CAP_SYS_TIME.
swapon	Deny start/stop swapping to file/device. Also gated by CAP_SYS_ADMIN.
swapoff	Deny start/stop swapping to file/device. Also gated by CAP_SYS_ADMIN.
sysfs	Obsolete syscall.
_sysctl	Obsolete, replaced by /proc/sys.
umount	Should be a privileged operation. Also gated by CAP_SYS_ADMIN.
umount2	Should be a privileged operation. Also gated by CAP_SYS_ADMIN.
unshare	Deny cloning new namespaces for processes. Also gated by CAP_SYS_ADMIN, with the exception of unshare –user.
uselib	Older syscall related to shared libraries, unused for a long time.
userfaultfd	Userspace page fault handling, largely needed for process migration.
ustat	Obsolete syscall.
vm86	In kernel x86 real mode virtual machine. Also gated by CAP_SYS_ADMIN.
vm86old	In kernel x86 real mode virtual machine. Also gated by CAP_SYS_ADMIN.