[compiler-rt] [sanitizer] Add TryMemCpy (PR #112668)
Vitaly Buka via llvm-commits
llvm-commits at lists.llvm.org
Thu Oct 17 16:59:11 PDT 2024
https://github.com/vitalybuka updated https://github.com/llvm/llvm-project/pull/112668
>From 23159ed20fa10bef1b63efb08d86861abf9362b2 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Wed, 16 Oct 2024 23:43:25 -0700
Subject: [PATCH 1/7] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20ch?=
=?UTF-8?q?anges=20to=20main=20this=20commit=20is=20based=20on?=
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Created using spr 1.3.4
[skip ci]
---
.../sanitizer_posix_libcdep.cpp | 51 ++++++++++++-------
.../tests/sanitizer_posix_test.cpp | 11 ++++
2 files changed, 44 insertions(+), 18 deletions(-)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
index 9ffb36f812c45d..f87af4bb3a5a6a 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
@@ -288,26 +288,41 @@ bool SignalContext::IsStackOverflow() const {
#endif // SANITIZER_GO
+static void SetNonBlock(int fd) {
+ int res = fcntl(fd, F_GETFL, 0);
+ CHECK(!internal_iserror(res, nullptr));
+
+ res |= O_NONBLOCK;
+ res = fcntl(fd, F_SETFL, res);
+ CHECK(!internal_iserror(res, nullptr));
+}
+
bool IsAccessibleMemoryRange(uptr beg, uptr size) {
- uptr page_size = GetPageSizeCached();
- // Checking too large memory ranges is slow.
- CHECK_LT(size, page_size * 10);
- int sock_pair[2];
- if (pipe(sock_pair))
- return false;
- uptr bytes_written =
- internal_write(sock_pair[1], reinterpret_cast<void *>(beg), size);
- int write_errno;
- bool result;
- if (internal_iserror(bytes_written, &write_errno)) {
- CHECK_EQ(EFAULT, write_errno);
- result = false;
- } else {
- result = (bytes_written == size);
+ while (size) {
+ // `read` from `sock_pair[0]` into a dummy buffer to free up the pipe buffer
+ // for more `write` is slower than just recreating a pipe.
+ int sock_pair[2];
+ if (pipe(sock_pair))
+ return false;
+
+ auto cleanup = at_scope_exit([&]() {
+ internal_close(sock_pair[0]);
+ internal_close(sock_pair[1]);
+ });
+
+ SetNonBlock(sock_pair[1]);
+
+ int write_errno;
+ uptr w = internal_write(sock_pair[1], reinterpret_cast<char *>(beg), size);
+ if (internal_iserror(w, &write_errno)) {
+ CHECK_EQ(EFAULT, write_errno);
+ return false;
+ }
+ size -= w;
+ beg += w;
}
- internal_close(sock_pair[0]);
- internal_close(sock_pair[1]);
- return result;
+
+ return true;
}
void PlatformPrepareForSandboxing(void *args) {
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
index bed19d15a8ec77..9feb22221f005e 100644
--- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
@@ -82,6 +82,17 @@ TEST(SanitizerCommon, IsAccessibleMemoryRange) {
munmap((void *)mem, 3 * page_size);
}
+TEST(SanitizerCommon, IsAccessibleMemoryRangeLarge) {
+ const int size = GetPageSize() * 10000;
+
+ uptr mem = (uptr)mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON,
+ -1, 0);
+
+ EXPECT_TRUE(IsAccessibleMemoryRange(mem, size));
+
+ munmap((void *)mem, size);
+}
+
} // namespace __sanitizer
#endif // SANITIZER_POSIX
>From 9571c266d478f2cb49a8005b0d19f40b3de72052 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Thu, 17 Oct 2024 15:47:37 -0700
Subject: [PATCH 2/7] rebase
Created using spr 1.3.4
---
compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp | 2 ++
compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp | 1 +
2 files changed, 3 insertions(+)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
index 6459c64985faab..e1117c1bec33fa 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
@@ -327,6 +327,8 @@ bool IsAccessibleMemoryRange(uptr beg, uptr size) {
}
bool TryMemCpy(void *dest, const void *src, uptr n) {
+ if (!n)
+ return true;
int fds[2];
CHECK_EQ(0, pipe(fds));
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
index 9e463796b2c678..03a841a6f438cb 100644
--- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
@@ -16,6 +16,7 @@
# include <pthread.h>
# include <sys/mman.h>
+# include <algorithm>
# include <numeric>
# include "gtest/gtest.h"
>From 2f85748304589ba78560fa8bedae42863c14c343 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Thu, 17 Oct 2024 15:51:24 -0700
Subject: [PATCH 3/7] move test into a different pr
Created using spr 1.3.4
---
.../tests/sanitizer_posix_test.cpp | 15 ---------------
1 file changed, 15 deletions(-)
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
index 03a841a6f438cb..658ca60175b3bd 100644
--- a/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_posix_test.cpp
@@ -127,21 +127,6 @@ TEST(SanitizerCommon, TryMemCpyNull) {
EXPECT_FALSE(TryMemCpy(dst.data(), nullptr, dst.size()));
}
-TEST(SanitizerCommon, TryMemCpyProtected) {
- const int page_size = GetPageSize();
- InternalMmapVector<char> src(3 * page_size);
- std::iota(src.begin(), src.end(), 123);
- std::vector<char> dst;
- // Protect the middle page.
- mprotect(src.data() + page_size, page_size, PROT_NONE);
-
- dst.assign(src.size(), 0);
- EXPECT_FALSE(TryMemCpy(dst.data(), src.data(), dst.size()));
-
- mprotect(src.data() + page_size, page_size, PROT_READ | PROT_WRITE);
- EXPECT_TRUE(std::equal(dst.begin(), dst.end(), src.begin()));
-}
-
} // namespace __sanitizer
#endif // SANITIZER_POSIX
>From 5337fadaa02592ed1e1fcdd9205ff0496c07a044 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Thu, 17 Oct 2024 16:20:05 -0700
Subject: [PATCH 4/7] EINTR
Created using spr 1.3.4
---
compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
index e1117c1bec33fa..f113b8ec58a15d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
@@ -357,7 +357,10 @@ bool TryMemCpy(void *dest, const void *src, uptr n) {
while (w) {
uptr r = internal_read(fds[0], d, w);
- CHECK(!internal_iserror(r, &e));
+ if(internal_iserror(r, &e)) {
+ CHECK_EQ(EINTR, e);
+ continue;
+ }
d += r;
w -= r;
>From 4e67e629322695226c4d7d0d2ee5d92effd99e53 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Thu, 17 Oct 2024 16:22:04 -0700
Subject: [PATCH 5/7] format
Created using spr 1.3.4
---
compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
index f113b8ec58a15d..7ee2319456d23e 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp
@@ -357,7 +357,7 @@ bool TryMemCpy(void *dest, const void *src, uptr n) {
while (w) {
uptr r = internal_read(fds[0], d, w);
- if(internal_iserror(r, &e)) {
+ if (internal_iserror(r, &e)) {
CHECK_EQ(EINTR, e);
continue;
}
>From 44a74388ff1fbdc301e7101927b191429976e3d0 Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Thu, 17 Oct 2024 16:55:14 -0700
Subject: [PATCH 6/7] Update comment
---
compiler-rt/lib/sanitizer_common/sanitizer_common.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.h b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
index 9b1e58f5e7a61d..785c2034cd884d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -270,8 +270,9 @@ extern uptr stoptheworld_tracer_ppid;
// Returns true if we can read a memory range.
bool IsAccessibleMemoryRange(uptr beg, uptr size);
-// Returns true if we can read a memory range starting at `src`, and copies
-// content into `dest`.
+// Attempts to copy `n` bytes from memory range starting at `src` to `dest`.
+// Returns true if the entire range can be read and copied, false otherwise.
+// If the copy fails, the contents of `dest` are undefined.
bool TryMemCpy(void *dest, const void *src, uptr n);
// Error report formatting.
>From cb4cb67045ab848fd54046141ab47e8650f7571f Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at google.com>
Date: Thu, 17 Oct 2024 16:59:01 -0700
Subject: [PATCH 7/7] Update comment
---
compiler-rt/lib/sanitizer_common/sanitizer_common.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.h b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
index 785c2034cd884d..3a28420ed02d78 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -268,11 +268,12 @@ class ScopedErrorReportLock {
extern uptr stoptheworld_tracer_pid;
extern uptr stoptheworld_tracer_ppid;
-// Returns true if we can read a memory range.
+// Returns true if the entire range can be read.
bool IsAccessibleMemoryRange(uptr beg, uptr size);
// Attempts to copy `n` bytes from memory range starting at `src` to `dest`.
-// Returns true if the entire range can be read and copied, false otherwise.
-// If the copy fails, the contents of `dest` are undefined.
+// Returns true if the entire range can be read. Returns `false` if any part of
+// the source range cannot be read, in which case the contents of `dest` are
+// undefined.
bool TryMemCpy(void *dest, const void *src, uptr n);
// Error report formatting.
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