git: f575573ca577 - main - Remove PT_GET_SC_ARGS_ALL
Konstantin Belousov
kib at FreeBSD.org
Thu Sep 16 17:26:53 UTC 2021
The branch main has been updated by kib:
URL: https://cgit.FreeBSD.org/src/commit/?id=f575573ca57716395ad88b962388a55d755cf6a7
commit f575573ca57716395ad88b962388a55d755cf6a7
Author: Konstantin Belousov <kib at FreeBSD.org>
AuthorDate: 2021-09-15 13:24:09 +0000
Commit: Konstantin Belousov <kib at FreeBSD.org>
CommitDate: 2021-09-16 17:11:27 +0000
Remove PT_GET_SC_ARGS_ALL
Reimplement bdf0f24bb16d556a5b by checking for the caller' ABI in
the implementation of PT_GET_SC_ARGS, and copying out everything if
it is Linuxolator.
Also fix a minor information leak: if PT_GET_SC_ARGS_ALL is done on the
thread reused after other process, it allows to read some number of that
thread last syscall arguments. Clear td_sa.args in thread_alloc().
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D31968
---
lib/libsysdecode/mktables | 2 +-
sys/amd64/linux/linux_ptrace.c | 18 ++++++++++--------
sys/compat/freebsd32/freebsd32_misc.c | 3 ---
sys/kern/kern_thread.c | 1 +
sys/kern/sys_process.c | 23 ++++-------------------
sys/sys/ptrace.h | 4 ----
6 files changed, 16 insertions(+), 35 deletions(-)
diff --git a/lib/libsysdecode/mktables b/lib/libsysdecode/mktables
index 1c263fd3b0b2..3d152a3a2646 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" "PT_GET_SC_ARGS_ALL"
+gen_table "ptraceop" "PT_[[:alnum:]_]+[[:space:]]+[0-9]+" "sys/ptrace.h"
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 70e52c528c72..eb39e3c9ada6 100644
--- a/sys/amd64/linux/linux_ptrace.c
+++ b/sys/amd64/linux/linux_ptrace.c
@@ -544,17 +544,19 @@ linux_ptrace_get_syscall_info(struct thread *td, pid_t pid,
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.
+ * The use of PT_GET_SC_ARGS there is special,
+ * implementation of PT_GET_SC_ARGS for Linux-ABI
+ * callers emulates 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,
+ error = kern_ptrace(td, PT_GET_SC_ARGS, pid,
&si.entry.args, sizeof(si.entry.args));
if (error != 0) {
- linux_msg(td, "PT_GET_SC_ARGS_ALL failed with error %d",
+ linux_msg(td, "PT_GET_SC_ARGS failed with error %d",
error);
return (error);
}
diff --git a/sys/compat/freebsd32/freebsd32_misc.c b/sys/compat/freebsd32/freebsd32_misc.c
index 01d772b35ee8..c417a64d286a 100644
--- a/sys/compat/freebsd32/freebsd32_misc.c
+++ b/sys/compat/freebsd32/freebsd32_misc.c
@@ -1032,9 +1032,6 @@ 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/kern_thread.c b/sys/kern/kern_thread.c
index cb35d565974d..65c5cc65c87e 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -762,6 +762,7 @@ thread_alloc(int pages)
return (NULL);
}
td->td_tid = tid;
+ bzero(&td->td_sa.args, sizeof(td->td_sa.args));
kmsan_thread_alloc(td);
cpu_thread_alloc(td);
EVENTHANDLER_DIRECT_INVOKE(thread_ctor, td);
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index e2d8042744d0..2c212edd0ae7 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -527,9 +527,6 @@ 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;
@@ -711,7 +708,6 @@ 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;
@@ -1011,21 +1007,10 @@ kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
break;
}
bzero(addr, sizeof(td2->td_sa.args));
- bcopy(td2->td_sa.args, addr, td2->td_sa.callp->sy_narg *
- 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));
+ /* See the explanation in linux_ptrace_get_syscall_info(). */
+ bcopy(td2->td_sa.args, addr, SV_PROC_ABI(td->td_proc) ==
+ SV_ABI_LINUX ? sizeof(td2->td_sa.args) :
+ td2->td_sa.callp->sy_narg * sizeof(register_t));
break;
case PT_GET_SC_RET:
diff --git a/sys/sys/ptrace.h b/sys/sys/ptrace.h
index 066a54f721c8..1e7c1c71056b 100644
--- a/sys/sys/ptrace.h
+++ b/sys/sys/ptrace.h
@@ -86,10 +86,6 @@
#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 */
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