git: 8371bf67d632 - stable/13 - linux: implement PTRACE_GET_SYSCALL_INFO
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Date: Mon, 21 Feb 2022 13:48:51 UTC
The branch stable/13 has been updated by trasz:
URL: https://cgit.FreeBSD.org/src/commit/?id=8371bf67d632ddc1117bbaa5956af260e62f26ac
commit 8371bf67d632ddc1117bbaa5956af260e62f26ac
Author: Edward Tomasz Napierala <trasz@FreeBSD.org>
AuthorDate: 2021-09-12 11:31:10 +0000
Commit: Edward Tomasz Napierala <trasz@FreeBSD.org>
CommitDate: 2022-02-21 13:23:50 +0000
linux: implement PTRACE_GET_SYSCALL_INFO
This is one of the pieces required to make modern (ie Focal)
strace(1) work.
Reviewed By: jhb (earlier version)
Sponsored by: EPSRC
Differential Revision: https://reviews.freebsd.org/D28212
(cherry picked from commit bdf0f24bb16d556a5b1e01cdfc087d08e91ac572)
---
lib/libsysdecode/mktables | 2 +-
sys/amd64/linux/linux_ptrace.c | 98 +++++++++++++++++++++++++++++++++--
sys/compat/freebsd32/freebsd32_misc.c | 3 ++
sys/kern/sys_process.c | 17 ++++++
sys/sys/ptrace.h | 4 ++
5 files changed, 120 insertions(+), 4 deletions(-)
diff --git a/lib/libsysdecode/mktables b/lib/libsysdecode/mktables
index 77cfa15bd1f5..f044784717c0 100644
--- a/lib/libsysdecode/mktables
+++ b/lib/libsysdecode/mktables
@@ -116,7 +116,7 @@ gen_table "nfssvcflags" "NFSSVC_[A-Z0-9]+[[:space:]]+0x[0-9]+" "nfs/
gen_table "pathconfname" "_PC_[A-Z4_]+[[:space:]]+[0-9]+" "sys/unistd.h"
gen_table "prio" "PRIO_[A-Z]+[[:space:]]+[0-9]" "sys/resource.h"
gen_table "procctlcmd" "PROC_[A-Z_]+[[:space:]]+[0-9]" "sys/procctl.h" "PROC_TRACE_CTL_"
-gen_table "ptraceop" "PT_[[:alnum:]_]+[[:space:]]+[0-9]+" "sys/ptrace.h"
+gen_table "ptraceop" "PT_[[:alnum:]_]+[[:space:]]+[0-9]+" "sys/ptrace.h" "PT_GET_SC_ARGS_ALL"
gen_table "quotactlcmds" "Q_[A-Z]+[[:space:]]+0x[0-9]+" "ufs/ufs/quota.h"
gen_table "rebootopt" "RB_[A-Z]+[[:space:]]+0x[0-9]+" "sys/reboot.h"
gen_table "rforkflags" "RF[A-Z]+[[:space:]]+\([0-9]+<<[0-9]+\)" "sys/unistd.h"
diff --git a/sys/amd64/linux/linux_ptrace.c b/sys/amd64/linux/linux_ptrace.c
index 6516453dd5e4..fa400e0d3529 100644
--- a/sys/amd64/linux/linux_ptrace.c
+++ b/sys/amd64/linux/linux_ptrace.c
@@ -94,6 +94,12 @@ __FBSDID("$FreeBSD$");
LINUX_PTRACE_O_TRACESECCOMP | LINUX_PTRACE_O_EXITKILL | \
LINUX_PTRACE_O_SUSPEND_SECCOMP)
+#define LINUX_PTRACE_SYSCALL_INFO_NONE 0
+#define LINUX_PTRACE_SYSCALL_INFO_ENTRY 1
+#define LINUX_PTRACE_SYSCALL_INFO_EXIT 2
+
+#define LINUX_ARCH_AMD64 0xc000003e
+
static int
map_signum(int lsig, int *bsigp)
{
@@ -173,6 +179,28 @@ struct linux_pt_reg {
l_ulong ss;
};
+struct syscall_info {
+ uint8_t op;
+ uint32_t arch;
+ uint64_t instruction_pointer;
+ uint64_t stack_pointer;
+ union {
+ struct {
+ uint64_t nr;
+ uint64_t args[6];
+ } entry;
+ struct {
+ int64_t rval;
+ uint8_t is_error;
+ } exit;
+ struct {
+ uint64_t nr;
+ uint64_t args[6];
+ uint32_t ret_data;
+ } seccomp;
+ };
+};
+
/*
* Translate amd64 ptrace registers between Linux and FreeBSD formats.
* The translation is pretty straighforward, for all registers but
@@ -529,11 +557,75 @@ linux_ptrace_seize(struct thread *td, pid_t pid, l_ulong addr, l_ulong data)
}
static int
-linux_ptrace_get_syscall_info(struct thread *td, pid_t pid, l_ulong addr, l_ulong data)
+linux_ptrace_get_syscall_info(struct thread *td, pid_t pid,
+ l_ulong addr, l_ulong data)
{
+ struct ptrace_lwpinfo lwpinfo;
+ struct ptrace_sc_ret sr;
+ struct reg b_reg;
+ struct syscall_info si;
+ int error;
- linux_msg(td, "PTRACE_GET_SYSCALL_INFO not implemented; returning EINVAL");
- return (EINVAL);
+ error = kern_ptrace(td, PT_LWPINFO, pid, &lwpinfo, sizeof(lwpinfo));
+ if (error != 0) {
+ linux_msg(td, "PT_LWPINFO failed with error %d", error);
+ return (error);
+ }
+
+ memset(&si, 0, sizeof(si));
+
+ if (lwpinfo.pl_flags & PL_FLAG_SCE) {
+ si.op = LINUX_PTRACE_SYSCALL_INFO_ENTRY;
+ si.entry.nr = lwpinfo.pl_syscall_code;
+ /*
+ * The reason for using PT_GET_SC_ARGS_ALL instead
+ * of PT_GET_SC_ARGS is to emulate Linux bug which strace(1)
+ * depends on: at initialization it tests whether ptrace works
+ * by calling close(2), or some other single-argument syscall,
+ * _with six arguments_, and then verifies whether it can
+ * fetch them all using this API; otherwise it bails out.
+ */
+ error = kern_ptrace(td, PT_GET_SC_ARGS_ALL, pid,
+ &si.entry.args, sizeof(si.entry.args));
+ if (error != 0) {
+ linux_msg(td, "PT_GET_SC_ARGS_ALL failed with error %d",
+ error);
+ return (error);
+ }
+ } else if (lwpinfo.pl_flags & PL_FLAG_SCX) {
+ si.op = LINUX_PTRACE_SYSCALL_INFO_EXIT;
+ error = kern_ptrace(td, PT_GET_SC_RET, pid, &sr, sizeof(sr));
+
+ if (error != 0) {
+ linux_msg(td, "PT_GET_SC_RET failed with error %d",
+ error);
+ return (error);
+ }
+
+ if (sr.sr_error == 0) {
+ si.exit.rval = sr.sr_retval[0];
+ si.exit.is_error = 0;
+ } else {
+ si.exit.rval = bsd_to_linux_errno(sr.sr_error);
+ si.exit.is_error = 1;
+ }
+ } else {
+ si.op = LINUX_PTRACE_SYSCALL_INFO_NONE;
+ }
+
+ error = kern_ptrace(td, PT_GETREGS, pid, &b_reg, 0);
+ if (error != 0)
+ return (error);
+
+ si.arch = LINUX_ARCH_AMD64;
+ si.instruction_pointer = b_reg.r_rip;
+ si.stack_pointer = b_reg.r_rsp;
+
+ error = copyout(&si, (void *)data, sizeof(si));
+ if (error == 0)
+ td->td_retval[0] = sizeof(si);
+
+ return (error);
}
int
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
index e56ab423f538..b7128debd97f 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -1025,6 +1025,9 @@ freebsd32_ptrace(struct thread *td, struct freebsd32_ptrace_args *uap)
r.pc.pc_limit = PAIR32TO64(off_t, r32.pc.pc_limit);
data = sizeof(r.pc);
break;
+ case PT_GET_SC_ARGS_ALL:
+ error = EINVAL;
+ break;
default:
addr = uap->addr;
break;
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index eb628c040cd9..75d950a57057 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -532,6 +532,9 @@ sys_ptrace(struct thread *td, struct ptrace_args *uap)
else
error = copyin(uap->addr, &r.pc, uap->data);
break;
+ case PT_GET_SC_ARGS_ALL:
+ error = EINVAL;
+ break;
default:
addr = uap->addr;
break;
@@ -713,6 +716,7 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
case PT_SET_EVENT_MASK:
case PT_DETACH:
case PT_GET_SC_ARGS:
+ case PT_GET_SC_ARGS_ALL:
sx_xlock(&proctree_lock);
proctree_locked = true;
break;
@@ -1016,6 +1020,19 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
sizeof(register_t));
break;
+ case PT_GET_SC_ARGS_ALL:
+ CTR1(KTR_PTRACE, "PT_GET_SC_ARGS_ALL: pid %d", p->p_pid);
+ if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
+#ifdef COMPAT_FREEBSD32
+ || (wrap32 && !safe)
+#endif
+ ) {
+ error = EINVAL;
+ break;
+ }
+ bcopy(td2->td_sa.args, addr, sizeof(td2->td_sa.args));
+ break;
+
case PT_GET_SC_RET:
if ((td2->td_dbgflags & (TDB_SCX)) == 0
#ifdef COMPAT_FREEBSD32
diff --git a/sys/sys/ptrace.h b/sys/sys/ptrace.h
index 4cd7a3fceaec..de7a49576c30 100644
--- a/sys/sys/ptrace.h
+++ b/sys/sys/ptrace.h
@@ -86,6 +86,10 @@
#define PT_VM_TIMESTAMP 40 /* Get VM version (timestamp) */
#define PT_VM_ENTRY 41 /* Get VM map (entry) */
+#ifdef _KERNEL
+#define PT_GET_SC_ARGS_ALL 42 /* Used by linux(4) */
+#endif
+
#define PT_FIRSTMACH 64 /* for machine-specific requests */
#include <machine/ptrace.h> /* machine-specific requests, if any */