[PATCH v4 0/3] Checkpoint Support for Syscall User Dispatch

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[PATCH v3 0/3] Checkpoint Support...

Gregory Price

21 Jan 2023 21 Jan '23

10:23 a.m.

v4: Whitespace s/CHECKPOINT_RESTART/CHECKPOINT_RESUME check test_syscall_work(SYSCALL_USER_DISPATCH) to determine if it's turned on or not in fs/proc/array and getter interface

v3: Kernel test robot static function fix Whitespace nitpicks

v2: Implements the getter/setter interface in ptrace rather than prctl

Syscall user dispatch makes it possible to cleanly intercept system calls from user-land. However, most transparent checkpoint software presently leverages some combination of ptrace and system call injection to place software in a ready-to-checkpoint state.

If Syscall User Dispatch is enabled at the time of being quiesced, injected system calls will subsequently be interposed upon and dispatched to the task's signal handler.

This patch set implements 3 features to enable software such as CRIU to cleanly interpose upon software leveraging syscall user dispatch.

- Implement PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH, akin to a similar feature for SECCOMP. This allows a ptracer to temporarily disable syscall user dispatch, making syscall injection possible.

- Implement an fs/proc extension that reports whether Syscall User Dispatch is being used in proc/status. A similar value is present for SECCOMP, and is used to determine whether special logic is needed during checkpoint/resume.

- Implement a getter interface for Syscall User Dispatch config info. To resume successfully, the checkpoint/resume software has to save and restore this information. Presently this configuration is write-only, with no way for C/R software to save it.

This was done in ptrace because syscall user dispatch is not part of uapi. The syscall_user_dispatch_config structure was added to the ptrace exports.

Gregory Price (3): ptrace,syscall_user_dispatch: Implement Syscall User Dispatch Suspension fs/proc/array: Add Syscall User Dispatch to proc status ptrace,syscall_user_dispatch: add a getter/setter for sud configuration

-- 2.39.0

Show replies by date

Gregory Price

21 Jan 21 Jan

10:23 a.m.

New subject: [PATCH v4 1/3] ptrace,syscall_user_dispatch: Implement Syscall User Dispatch Suspension

Adds PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH to ptrace options, and modify Syscall User Dispatch to suspend interception when enabled.

This is modeled after the SUSPEND_SECCOMP feature, which suspends SECCOMP interposition. Without doing this, software like CRIU will inject system calls into a process and be intercepted by Syscall User Dispatch, either causing a crash (due to blocked signals) or the delivery of those signals to a ptracer (not the intended behavior).

Since Syscall User Dispatch is not a privileged feature, a check for permissions is not required, however attempting to set this option when CONFIG_CHECKPOINT_RESTORE it not supported should be disallowed, as its intended use is checkpoint/resume.

Signed-off-by: Gregory Price gregory.price@memverge.com Acked-by: Peter Zijlstra (Intel) peterz@infradead.org --- include/linux/ptrace.h | 2 ++ include/uapi/linux/ptrace.h | 6 +++++- kernel/entry/syscall_user_dispatch.c | 5 +++++ kernel/ptrace.c | 4 ++++ 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index eaaef3ffec22..461ae5c99d57 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -45,6 +45,8 @@ extern int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,

#define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT) #define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT) +#define PT_SUSPEND_SYSCALL_USER_DISPATCH \ + (PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH << PT_OPT_FLAG_SHIFT)

extern long arch_ptrace(struct task_struct *child, long request, unsigned long addr, unsigned long data); diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h index 195ae64a8c87..ba9e3f19a22c 100644 --- a/include/uapi/linux/ptrace.h +++ b/include/uapi/linux/ptrace.h @@ -146,9 +146,13 @@ struct ptrace_rseq_configuration { /* eventless options */ #define PTRACE_O_EXITKILL (1 << 20) #define PTRACE_O_SUSPEND_SECCOMP (1 << 21) +#define PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH (1 << 22)

#include <asm/ptrace.h>

diff --git a/kernel/entry/syscall_user_dispatch.c b/kernel/entry/syscall_user_dispatch.c index 0b6379adff6b..b5ec75164805 100644 --- a/kernel/entry/syscall_user_dispatch.c +++ b/kernel/entry/syscall_user_dispatch.c @@ -8,6 +8,7 @@ #include <linux/uaccess.h> #include <linux/signal.h> #include <linux/elf.h> +#include <linux/ptrace.h>

#include <linux/sched/signal.h> #include <linux/sched/task_stack.h> @@ -36,6 +37,10 @@ bool syscall_user_dispatch(struct pt_regs *regs) struct syscall_user_dispatch *sd = &current->syscall_dispatch; char state;

+ if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) && + unlikely(current->ptrace & PT_SUSPEND_SYSCALL_USER_DISPATCH)) + return false; + if (likely(instruction_pointer(regs) - sd->offset < sd->len)) return false;

diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 54482193e1ed..a348b68d07a2 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -370,6 +370,10 @@ static int check_ptrace_options(unsigned long data) if (data & ~(unsigned long)PTRACE_O_MASK) return -EINVAL;

+ if (unlikely(data & PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH) && + (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE))) + return -EINVAL; + if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) || !IS_ENABLED(CONFIG_SECCOMP))

-- 2.39.0

Gregory Price

10:23 a.m.

New subject: [PATCH v4 2/3] fs/proc/array: Add Syscall User Dispatch to proc status

Report the value of test_syscall_work(SYSCALL_USER_DISPATCH)) in proc/status.

This provides an indicator to userland checkpoint/resume software that it must manage special signal conditions (similar to SECCOMP)

Signed-off-by: Gregory Price gregory.price@memverge.com --- fs/proc/array.c | 8 ++++++++ 1 file changed, 8 insertions(+)

diff --git a/fs/proc/array.c b/fs/proc/array.c index 49283b8103c7..2275ac153c4c 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -428,6 +428,13 @@ static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm) seq_printf(m, "THP_enabled:\t%d\n", thp_enabled); }

+static inline void task_syscall_user_dispatch(struct seq_file *m, + struct task_struct *p) +{ + seq_put_decimal_ull(m, "\nSyscall_user_dispatch:\t", + test_syscall_work(SYSCALL_USER_DISPATCH)); +} + int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { @@ -451,6 +458,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, task_cpus_allowed(m, task); cpuset_task_status_allowed(m, task); task_context_switch_counts(m, task); + task_syscall_user_dispatch(m, task); return 0; }

-- 2.39.0

kernel test robot

1:04 p.m.

New subject: [PATCH v4 2/3] fs/proc/array: Add Syscall User Dispatch to proc status

Hi Gregory,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master] [also build test ERROR on v6.2-rc4 next-20230120] [cannot apply to tip/core/entry] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Gregory-Price/ptrace-syscall_... patch link: https://lore.kernel.org/r/20230121102316.331935-3-gregory.price%40memverge.c... patch subject: [PATCH v4 2/3] fs/proc/array: Add Syscall User Dispatch to proc status config: arc-randconfig-r043-20230119 (https://download.01.org/0day-ci/archive/20230121/202301212030.oAj9QJnD-lkp@i...) compiler: arceb-elf-gcc (GCC) 12.1.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/a2cb8440d45e7d3030e7349c7c5989... git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Gregory-Price/ptrace-syscall_user_dispatch-Implement-Syscall-User-Dispatch-Suspension/20230121-182401 git checkout a2cb8440d45e7d3030e7349c7c598971a951e5f2 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arc olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot lkp@intel.com

All errors (new ones prefixed by >>):

In file included from include/asm-generic/current.h:5, from arch/arc/include/asm/current.h:20, from include/linux/sched.h:12, from include/linux/time_namespace.h:6, from fs/proc/array.c:59: fs/proc/array.c: In function 'task_syscall_user_dispatch':

...

...
include/linux/thread_info.h:168:52: error: 'TIF_SYSCALL_USER_DISPATCH' undeclared (first use in this function); did you mean 'PR_SET_SYSCALL_USER_DISPATCH'?

168 | test_ti_thread_flag(current_thread_info(), TIF_##fl) | ^~~~ fs/proc/array.c:435:29: note: in expansion of macro 'test_syscall_work' 435 | test_syscall_work(SYSCALL_USER_DISPATCH)); | ^~~~~~~~~~~~~~~~~ include/linux/thread_info.h:168:52: note: each undeclared identifier is reported only once for each function it appears in 168 | test_ti_thread_flag(current_thread_info(), TIF_##fl) | ^~~~ fs/proc/array.c:435:29: note: in expansion of macro 'test_syscall_work' 435 | test_syscall_work(SYSCALL_USER_DISPATCH)); | ^~~~~~~~~~~~~~~~~

vim +168 include/linux/thread_info.h

3136b93c3fb2b7 Gabriel Krisman Bertazi 2020-11-16 164 3136b93c3fb2b7 Gabriel Krisman Bertazi 2020-11-16 165 #define set_syscall_work(fl) \ 5903f61e035320 Gabriel Krisman Bertazi 2020-11-23 166 set_ti_thread_flag(current_thread_info(), TIF_##fl) 3136b93c3fb2b7 Gabriel Krisman Bertazi 2020-11-16 167 #define test_syscall_work(fl) \ 5903f61e035320 Gabriel Krisman Bertazi 2020-11-23 @168 test_ti_thread_flag(current_thread_info(), TIF_##fl) 3136b93c3fb2b7 Gabriel Krisman Bertazi 2020-11-16 169 #define clear_syscall_work(fl) \ 5903f61e035320 Gabriel Krisman Bertazi 2020-11-23 170 clear_ti_thread_flag(current_thread_info(), TIF_##fl) 3136b93c3fb2b7 Gabriel Krisman Bertazi 2020-11-16 171

-- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests

kernel test robot

1:04 p.m.

New subject: [PATCH v4 2/3] fs/proc/array: Add Syscall User Dispatch to proc status

Hi Gregory,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master] [cannot apply to tip/core/entry] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information]

url: https://github.com/intel-lab-lkp/linux/commits/Gregory-Price/ptrace-syscall_... patch link: https://lore.kernel.org/r/20230121102316.331935-3-gregory.price%40memverge.c... patch subject: [PATCH v4 2/3] fs/proc/array: Add Syscall User Dispatch to proc status config: hexagon-randconfig-r041-20230119 (https://download.01.org/0day-ci/archive/20230121/202301212023.KjbRqxRz-lkp@i...) compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 4196ca3278f78c6e19246e54ab0ecb364e37d66a) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/a2cb8440d45e7d3030e7349c7c5989... git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Gregory-Price/ptrace-syscall_user_dispatch-Implement-Syscall-User-Dispatch-Suspension/20230121-182401 git checkout a2cb8440d45e7d3030e7349c7c598971a951e5f2 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/

If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot lkp@intel.com

All errors (new ones prefixed by >>):

In file included from fs/proc/array.c:61: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __raw_readb(PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu' #define __le16_to_cpu(x) ((__force __u16)(__le16)(x)) ^ In file included from fs/proc/array.c:61: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr)); ~~~~~~~~~~ ^ include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu' #define __le32_to_cpu(x) ((__force __u32)(__le32)(x)) ^ In file included from fs/proc/array.c:61: In file included from include/linux/kernel_stat.h:9: In file included from include/linux/interrupt.h:11: In file included from include/linux/hardirq.h:11: In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1: In file included from include/asm-generic/hardirq.h:17: In file included from include/linux/irq.h:20: In file included from include/linux/io.h:13: In file included from arch/hexagon/include/asm/io.h:334: include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writeb(value, PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^ include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic] __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr); ~~~~~~~~~~ ^

...

...
fs/proc/array.c:435:8: error: use of undeclared identifier 'TIF_SYSCALL_USER_DISPATCH'

test_syscall_work(SYSCALL_USER_DISPATCH)); ^ include/linux/thread_info.h:168:45: note: expanded from macro 'test_syscall_work' test_ti_thread_flag(current_thread_info(), TIF_##fl) ^ <scratch space>:70:1: note: expanded from here TIF_SYSCALL_USER_DISPATCH ^ 6 warnings and 1 error generated.

vim +/TIF_SYSCALL_USER_DISPATCH +435 fs/proc/array.c

430 431 static inline void task_syscall_user_dispatch(struct seq_file *m, 432 struct task_struct *p) 433 { 434 seq_put_decimal_ull(m, "\nSyscall_user_dispatch:\t",

...

435 test_syscall_work(SYSCALL_USER_DISPATCH));

436 } 437

-- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests

kernel test robot

1:04 p.m.

New subject: [PATCH v4 2/3] fs/proc/array: Add Syscall User Dispatch to proc status

Hi Gregory,

Thank you for the patch! Yet something to improve:

url: https://github.com/intel-lab-lkp/linux/commits/Gregory-Price/ptrace-syscall_... patch link: https://lore.kernel.org/r/20230121102316.331935-3-gregory.price%40memverge.c... patch subject: [PATCH v4 2/3] fs/proc/array: Add Syscall User Dispatch to proc status config: hexagon-randconfig-r016-20230119 (https://download.01.org/0day-ci/archive/20230121/202301212030.OheLeUFY-lkp@i...) compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 4196ca3278f78c6e19246e54ab0ecb364e37d66a) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel-lab-lkp/linux/commit/a2cb8440d45e7d3030e7349c7c5989... git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Gregory-Price/ptrace-syscall_user_dispatch-Implement-Syscall-User-Dispatch-Suspension/20230121-182401 git checkout a2cb8440d45e7d3030e7349c7c598971a951e5f2 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/

If you fix the issue, kindly add following tag where applicable | Reported-by: kernel test robot lkp@intel.com

All errors (new ones prefixed by >>):

...

...
fs/proc/array.c:435:8: error: use of undeclared identifier 'TIF_SYSCALL_USER_DISPATCH'

test_syscall_work(SYSCALL_USER_DISPATCH)); ^ include/linux/thread_info.h:168:45: note: expanded from macro 'test_syscall_work' test_ti_thread_flag(current_thread_info(), TIF_##fl) ^ <scratch space>:37:1: note: expanded from here TIF_SYSCALL_USER_DISPATCH ^ 6 warnings and 1 error generated.

vim +/TIF_SYSCALL_USER_DISPATCH +435 fs/proc/array.c

430 431 static inline void task_syscall_user_dispatch(struct seq_file *m, 432 struct task_struct *p) 433 { 434 seq_put_decimal_ull(m, "\nSyscall_user_dispatch:\t",

...

435 test_syscall_work(SYSCALL_USER_DISPATCH));

436 } 437

-- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests

Gregory Price

10:23 a.m.

New subject: [PATCH v4 3/3] ptrace,syscall_user_dispatch: add a getter/setter for sud configuration

Implement ptrace getter/setter interface for syscall user dispatch.

Presently, these settings are write-only via prctl, making it impossible to implement transparent checkpoint (coordination with the software is required).

This is modeled after a similar interface for SECCOMP, which can have its configuration dumped by ptrace for software like CRIU.

Signed-off-by: Gregory Price gregory.price@memverge.com --- .../admin-guide/syscall-user-dispatch.rst | 5 +- include/linux/syscall_user_dispatch.h | 19 ++++++++ include/uapi/linux/ptrace.h | 10 ++++ kernel/entry/syscall_user_dispatch.c | 46 +++++++++++++++++++ kernel/ptrace.c | 9 ++++ 5 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/syscall-user-dispatch.rst b/Documentation/admin-guide/syscall-user-dispatch.rst index 60314953c728..a23ae21a1d5b 100644 --- a/Documentation/admin-guide/syscall-user-dispatch.rst +++ b/Documentation/admin-guide/syscall-user-dispatch.rst @@ -43,7 +43,10 @@ doesn't rely on any of the syscall ABI to make the filtering. It uses only the syscall dispatcher address and the userspace key.

As the ABI of these intercepted syscalls is unknown to Linux, these -syscalls are not instrumentable via ptrace or the syscall tracepoints. +syscalls are not instrumentable via ptrace or the syscall tracepoints, +however an interfaces to suspend, checkpoint, and restore syscall user +dispatch configuration has been added to ptrace to assist userland +checkpoint/restart software.

Interface --------- diff --git a/include/linux/syscall_user_dispatch.h b/include/linux/syscall_user_dispatch.h index a0ae443fb7df..9e1bd0d87c1e 100644 --- a/include/linux/syscall_user_dispatch.h +++ b/include/linux/syscall_user_dispatch.h @@ -22,6 +22,13 @@ int set_syscall_user_dispatch(unsigned long mode, unsigned long offset, #define clear_syscall_work_syscall_user_dispatch(tsk) \ clear_task_syscall_work(tsk, SYSCALL_USER_DISPATCH)

+int syscall_user_dispatch_get_config(struct task_struct *task, unsigned long size, + void __user *data); + +int syscall_user_dispatch_set_config(struct task_struct *task, unsigned long size, + void __user *data); + + #else struct syscall_user_dispatch {};

@@ -35,6 +42,18 @@ static inline void clear_syscall_work_syscall_user_dispatch(struct task_struct * { }

+static inline int syscall_user_dispatch_get_config(struct task_struct *task, unsigned long size, + void __user *data) +{ + return -EINVAL; +} + +static inline int syscall_user_dispatch_set_config(struct task_struct *task, unsigned long size, + void __user *data) +{ + return -EINVAL; +} + #endif /* CONFIG_GENERIC_ENTRY */

#endif /* _SYSCALL_USER_DISPATCH_H */ diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h index ba9e3f19a22c..8b93c78189b5 100644 --- a/include/uapi/linux/ptrace.h +++ b/include/uapi/linux/ptrace.h @@ -112,6 +112,16 @@ struct ptrace_rseq_configuration { __u32 pad; };

+#define PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG 0x4210 +#define PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG 0x4211 +struct syscall_user_dispatch_config { + __u64 mode; + __s8 *selector; + __u64 offset; + __u64 len; + __u8 on_dispatch; +}; + /* * These values are stored in task->ptrace_message * by ptrace_stop to describe the current syscall-stop. diff --git a/kernel/entry/syscall_user_dispatch.c b/kernel/entry/syscall_user_dispatch.c index b5ec75164805..a303c8de59af 100644 --- a/kernel/entry/syscall_user_dispatch.c +++ b/kernel/entry/syscall_user_dispatch.c @@ -111,3 +111,49 @@ int set_syscall_user_dispatch(unsigned long mode, unsigned long offset,

return 0; } + +int syscall_user_dispatch_get_config(struct task_struct *task, unsigned long size, + void __user *data) +{ + struct syscall_user_dispatch *sd = &task->syscall_dispatch; + struct syscall_user_dispatch_config config; + + if (size != sizeof(struct syscall_user_dispatch_config)) + return -EINVAL; + + if (test_syscall_work(SYSCALL_USER_DISPATCH)) + config.mode = PR_SYS_DISPATCH_ON; + else + config.mode = PR_SYS_DISPATCH_OFF; + + config.offset = sd->offset; + config.len = sd->len; + config.selector = sd->selector; + config.on_dispatch = sd->on_dispatch; + + if (copy_to_user(data, &config, sizeof(config))) + return -EFAULT; + + return 0; +} + +int syscall_user_dispatch_set_config(struct task_struct *task, unsigned long size, + void __user *data) +{ + struct syscall_user_dispatch_config config; + int ret; + + if (size != sizeof(struct syscall_user_dispatch_config)) + return -EINVAL; + + if (copy_from_user(&config, data, sizeof(config))) + return -EFAULT; + + ret = set_syscall_user_dispatch(config.mode, config.offset, config.len, + config.selector); + if (ret) + return ret; + + task->syscall_dispatch.on_dispatch = config.on_dispatch; + return 0; +} diff --git a/kernel/ptrace.c b/kernel/ptrace.c index a348b68d07a2..76de46e080e2 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -32,6 +32,7 @@ #include <linux/compat.h> #include <linux/sched/signal.h> #include <linux/minmax.h> +#include <linux/syscall_user_dispatch.h>

#include <asm/syscall.h> /* for syscall_get_* */

@@ -1263,6 +1264,14 @@ int ptrace_request(struct task_struct *child, long request, break; #endif

+ case PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG: + ret = syscall_user_dispatch_set_config(child, addr, datavp); + break; + + case PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG: + ret = syscall_user_dispatch_get_config(child, addr, datavp); + break; + default: break; }

-- 2.39.0

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Gregory Price
kernel test robot