commit b064131bdf099d3647b4501e5d15391e1e9623e6
Author: Mark Wielaard <mark@klomp.org>
Date: Thu May 30 00:29:58 2019 +0200
linux x86 and amd64 memory protection key syscalls.
This implements minimal support for the pkey_alloc, pkey_free and
pkey_mprotect syscalls. pkey_alloc will simply indicate that pkeys
are not supported. pkey_free always fails. pkey_mprotect works just
like mprotect if the special pkey -1 is provided.
https://bugs.kde.org/show_bug.cgi?id=408091
diff --git a/coregrind/m_syswrap/priv_syswrap-generic.h b/coregrind/m_syswrap/priv_syswrap-generic.h
index 88530f0..3e1c8b6 100644
--- a/coregrind/m_syswrap/priv_syswrap-generic.h
+++ b/coregrind/m_syswrap/priv_syswrap-generic.h
@@ -106,6 +106,10 @@ extern Bool
ML_(handle_auxv_open)(SyscallStatus *status, const HChar *filename,
int flags);
+/* Helper function for generic mprotect and linux pkey_mprotect. */
+extern void handle_sys_mprotect (ThreadId tid, SyscallStatus *status,
+ Addr *addr, SizeT *len, Int *prot);
+
DECL_TEMPLATE(generic, sys_ni_syscall); // * P -- unimplemented
DECL_TEMPLATE(generic, sys_exit);
DECL_TEMPLATE(generic, sys_fork);
diff --git a/coregrind/m_syswrap/priv_syswrap-linux.h b/coregrind/m_syswrap/priv_syswrap-linux.h
index 5cf5407..2471524 100644
--- a/coregrind/m_syswrap/priv_syswrap-linux.h
+++ b/coregrind/m_syswrap/priv_syswrap-linux.h
@@ -299,6 +299,11 @@ DECL_TEMPLATE(linux, sys_bpf);
// Linux-specific (new in Linux 4.11)
DECL_TEMPLATE(linux, sys_statx);
+// Linux-specific memory protection key syscalls (since Linux 4.9)
+DECL_TEMPLATE(linux, sys_pkey_alloc);
+DECL_TEMPLATE(linux, sys_pkey_free);
+DECL_TEMPLATE(linux, sys_pkey_mprotect);
+
/* ---------------------------------------------------------------------
Wrappers for sockets and ipc-ery. These are split into standalone
procedures because x86-linux hides them inside multiplexors
diff --git a/coregrind/m_syswrap/syswrap-amd64-linux.c b/coregrind/m_syswrap/syswrap-amd64-linux.c
index d4fe413..2d6b95f 100644
--- a/coregrind/m_syswrap/syswrap-amd64-linux.c
+++ b/coregrind/m_syswrap/syswrap-amd64-linux.c
@@ -863,6 +863,10 @@ static SyscallTableEntry syscall_table[] = {
LINX_(__NR_membarrier, sys_membarrier), // 324
LINX_(__NR_copy_file_range, sys_copy_file_range), // 326
+
+ LINXY(__NR_pkey_mprotect, sys_pkey_mprotect), // 329
+ LINX_(__NR_pkey_alloc, sys_pkey_alloc), // 330
+ LINX_(__NR_pkey_free, sys_pkey_free), // 331
};
SyscallTableEntry* ML_(get_linux_syscall_entry) ( UInt sysno )
diff --git a/coregrind/m_syswrap/syswrap-generic.c b/coregrind/m_syswrap/syswrap-generic.c
index 0b64919..01191f6 100644
--- a/coregrind/m_syswrap/syswrap-generic.c
+++ b/coregrind/m_syswrap/syswrap-generic.c
@@ -3842,12 +3842,28 @@ PRE(sys_mprotect)
PRE_REG_READ3(long, "mprotect",
unsigned long, addr, vki_size_t, len, unsigned long, prot);
- if (!ML_(valid_client_addr)(ARG1, ARG2, tid, "mprotect")) {
+ Addr addr = ARG1;
+ SizeT len = ARG2;
+ Int prot = ARG3;
+
+ handle_sys_mprotect (tid, status, &addr, &len, &prot);
+
+ ARG1 = addr;
+ ARG2 = len;
+ ARG3 = prot;
+}
+/* This will be called from the generic mprotect, or the linux specific
+ pkey_mprotect. Pass pointers to ARG1, ARG2 and ARG3 as addr, len and prot,
+ they might be adjusted and have to assigned back to ARG1, ARG2 and ARG3. */
+void handle_sys_mprotect(ThreadId tid, SyscallStatus* status,
+ Addr *addr, SizeT *len, Int *prot)
+{
+ if (!ML_(valid_client_addr)(*addr, *len, tid, "mprotect")) {
SET_STATUS_Failure( VKI_ENOMEM );
}
#if defined(VKI_PROT_GROWSDOWN)
else
- if (ARG3 & (VKI_PROT_GROWSDOWN|VKI_PROT_GROWSUP)) {
+ if (*prot & (VKI_PROT_GROWSDOWN|VKI_PROT_GROWSUP)) {
/* Deal with mprotects on growable stack areas.
The critical files to understand all this are mm/mprotect.c
@@ -3862,8 +3878,8 @@ PRE(sys_mprotect)
The sanity check provided by the kernel is that the vma must
have the VM_GROWSDOWN/VM_GROWSUP flag set as appropriate. */
- UInt grows = ARG3 & (VKI_PROT_GROWSDOWN|VKI_PROT_GROWSUP);
- NSegment const *aseg = VG_(am_find_nsegment)(ARG1);
+ UInt grows = *prot & (VKI_PROT_GROWSDOWN|VKI_PROT_GROWSUP);
+ NSegment const *aseg = VG_(am_find_nsegment)(*addr);
NSegment const *rseg;
vg_assert(aseg);
@@ -3874,10 +3890,10 @@ PRE(sys_mprotect)
&& rseg->kind == SkResvn
&& rseg->smode == SmUpper
&& rseg->end+1 == aseg->start) {
- Addr end = ARG1 + ARG2;
- ARG1 = aseg->start;
- ARG2 = end - aseg->start;
- ARG3 &= ~VKI_PROT_GROWSDOWN;
+ Addr end = *addr + *len;
+ *addr = aseg->start;
+ *len = end - aseg->start;
+ *prot &= ~VKI_PROT_GROWSDOWN;
} else {
SET_STATUS_Failure( VKI_EINVAL );
}
@@ -3887,8 +3903,8 @@ PRE(sys_mprotect)
&& rseg->kind == SkResvn
&& rseg->smode == SmLower
&& aseg->end+1 == rseg->start) {
- ARG2 = aseg->end - ARG1 + 1;
- ARG3 &= ~VKI_PROT_GROWSUP;
+ *len = aseg->end - *addr + 1;
+ *prot &= ~VKI_PROT_GROWSUP;
} else {
SET_STATUS_Failure( VKI_EINVAL );
}
diff --git a/coregrind/m_syswrap/syswrap-linux.c b/coregrind/m_syswrap/syswrap-linux.c
index 810ca24..5452b8d 100644
--- a/coregrind/m_syswrap/syswrap-linux.c
+++ b/coregrind/m_syswrap/syswrap-linux.c
@@ -12120,6 +12120,76 @@ PRE(sys_copy_file_range)
}
}
+PRE(sys_pkey_alloc)
+{
+ PRINT("pkey_alloc (%lu, %lu)", ARG1, ARG2);
+
+ PRE_REG_READ2(long, "pkey_alloc",
+ unsigned long, "flags",
+ unsigned long, "access_rights");
+
+ /* The kernel says: pkey_alloc() is always safe to call regardless of
+ whether or not the operating system supports protection keys. It can be
+ used in lieu of any other mechanism for detecting pkey support and will
+ simply fail with the error ENOSPC if the operating system has no pkey
+ support.
+
+ So we simply always return ENOSPC to signal memory protection keys are
+ not supported under valgrind, unless there are unknown flags, then we
+ return EINVAL. */
+ unsigned long pkey_flags = ARG1;
+ if (pkey_flags != 0)
+ SET_STATUS_Failure( VKI_EINVAL );
+ else
+ SET_STATUS_Failure( VKI_ENOSPC );
+}
+
+PRE(sys_pkey_free)
+{
+ PRINT("pkey_free (%" FMT_REGWORD "u )", ARG1);
+
+ PRE_REG_READ1(long, "pkey_free",
+ unsigned long, "pkey");
+
+ /* Since pkey_alloc () can never succeed, see above, freeing any pkey is
+ always an error. */
+ SET_STATUS_Failure( VKI_EINVAL );
+}
+
+PRE(sys_pkey_mprotect)
+{
+ PRINT("sys_pkey_mprotect ( %#" FMT_REGWORD "x, %" FMT_REGWORD "u, %"
+ FMT_REGWORD "u %" FMT_REGWORD "u )", ARG1, ARG2, ARG3, ARG4);
+ PRE_REG_READ4(long, "pkey_mprotect",
+ unsigned long, addr, vki_size_t, len, unsigned long, prot,
+ unsigned long, pkey);
+
+ Addr addr = ARG1;
+ SizeT len = ARG2;
+ Int prot = ARG3;
+ Int pkey = ARG4;
+
+ /* Since pkey_alloc () can never succeed, see above, any pkey is
+ invalid. Except for -1, then pkey_mprotect acts just like mprotect. */
+ if (pkey != -1)
+ SET_STATUS_Failure( VKI_EINVAL );
+ else
+ handle_sys_mprotect (tid, status, &addr, &len, &prot);
+
+ ARG1 = addr;
+ ARG2 = len;
+ ARG3 = prot;
+}
+
+POST(sys_pkey_mprotect)
+{
+ Addr addr = ARG1;
+ SizeT len = ARG2;
+ Int prot = ARG3;
+
+ ML_(notify_core_and_tool_of_mprotect)(addr, len, prot);
+}
+
#undef PRE
#undef POST
diff --git a/coregrind/m_syswrap/syswrap-x86-linux.c b/coregrind/m_syswrap/syswrap-x86-linux.c
index ad54cf6..3829fa4 100644
--- a/coregrind/m_syswrap/syswrap-x86-linux.c
+++ b/coregrind/m_syswrap/syswrap-x86-linux.c
@@ -1608,6 +1608,9 @@ static SyscallTableEntry syscall_table[] = {
LINX_(__NR_copy_file_range, sys_copy_file_range), // 377
+ LINXY(__NR_pkey_mprotect, sys_pkey_mprotect), // 380
+ LINX_(__NR_pkey_alloc, sys_pkey_alloc), // 381
+ LINX_(__NR_pkey_free, sys_pkey_free), // 382
LINXY(__NR_statx, sys_statx), // 383
/* Explicitly not supported on i386 yet. */