[Lldb-commits] [lldb] 555cd03 - [lldb] Correct format of qMemTags type field
David Spickett via lldb-commits
lldb-commits at lists.llvm.org
Fri Jul 30 03:07:04 PDT 2021
Author: David Spickett
Date: 2021-07-30T11:06:57+01:00
New Revision: 555cd03193c9c098d787bec93eadfe43b179db9c
URL: https://github.com/llvm/llvm-project/commit/555cd03193c9c098d787bec93eadfe43b179db9c
DIFF: https://github.com/llvm/llvm-project/commit/555cd03193c9c098d787bec93eadfe43b179db9c.diff
LOG: [lldb] Correct format of qMemTags type field
The type field is a signed integer.
(https://sourceware.org/gdb/current/onlinedocs/gdb/General-Query-Packets.html)
However it's not packed in the packet in the way
you might think. For example the type -1 should be:
qMemTags:<addr>,<len>:ffffffff
Instead of:
qMemTags:<addr>,<len>:-1
This change makes lldb-server's parsing more strict
and adds more tests to check that we handle negative types
correctly in lldb and lldb-server.
We only support one tag type value at this point,
for AArch64 MTE, which is positive. So this doesn't change
any of those interactions. It just brings us in line with GDB.
Also check that the test target has MTE. Previously
we just checked that we were AArch64 with a toolchain
that supports MTE.
Finally, update the tag type check for QMemTags to use
the same conversion steps that qMemTags now does.
Using static_cast can invoke UB and though we do do a limit
check to avoid this, I think it's clearer with the new method.
Reviewed By: omjavaid
Differential Revision: https://reviews.llvm.org/D104914
Added:
Modified:
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py
lldb/unittests/Process/gdb-remote/GDBRemoteCommunicationClientTest.cpp
Removed:
################################################################################
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index 5e69b5793f9f0..8e1f6bc29a6f8 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
@@ -3474,15 +3474,31 @@ GDBRemoteCommunicationServerLLGS::Handle_qMemTags(
if (packet.GetBytesLeft() < 1 || packet.GetChar() != ':')
return SendIllFormedResponse(packet, invalid_type_err);
- int32_t type =
- packet.GetS32(std::numeric_limits<int32_t>::max(), /*base=*/16);
- if (type == std::numeric_limits<int32_t>::max() ||
+ // Type is a signed integer but packed into the packet as its raw bytes.
+ // However, our GetU64 uses strtoull which allows +/-. We do not want this.
+ const char *first_type_char = packet.Peek();
+ if (first_type_char && (*first_type_char == '+' || *first_type_char == '-'))
+ return SendIllFormedResponse(packet, invalid_type_err);
+
+ // Extract type as unsigned then cast to signed.
+ // Using a uint64_t here so that we have some value outside of the 32 bit
+ // range to use as the invalid return value.
+ uint64_t raw_type =
+ packet.GetU64(std::numeric_limits<uint64_t>::max(), /*base=*/16);
+
+ if ( // Make sure the cast below would be valid
+ raw_type > std::numeric_limits<uint32_t>::max() ||
// To catch inputs like "123aardvark" that will parse but clearly aren't
// valid in this case.
packet.GetBytesLeft()) {
return SendIllFormedResponse(packet, invalid_type_err);
}
+ // First narrow to 32 bits otherwise the copy into type would take
+ // the wrong 4 bytes on big endian.
+ uint32_t raw_type_32 = raw_type;
+ int32_t type = reinterpret_cast<int32_t &>(raw_type_32);
+
StreamGDBRemote response;
std::vector<uint8_t> tags;
Status error = m_current_process->ReadMemoryTags(type, addr, length, tags);
@@ -3552,7 +3568,11 @@ GDBRemoteCommunicationServerLLGS::Handle_QMemTags(
packet.GetU64(std::numeric_limits<uint64_t>::max(), /*base=*/16);
if (raw_type > std::numeric_limits<uint32_t>::max())
return SendIllFormedResponse(packet, invalid_type_err);
- int32_t type = static_cast<int32_t>(raw_type);
+
+ // First narrow to 32 bits. Otherwise the copy below would get the wrong
+ // 4 bytes on big endian.
+ uint32_t raw_type_32 = raw_type;
+ int32_t type = reinterpret_cast<int32_t &>(raw_type_32);
// Tag data
if (packet.GetBytesLeft() < 1 || packet.GetChar() != ':')
diff --git a/lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py b/lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py
index d292f20993c66..983e1aa54b327 100644
--- a/lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py
+++ b/lldb/test/API/tools/lldb-server/memory-tagging/TestGdbRemoteMemoryTagging.py
@@ -105,13 +105,20 @@ def test_qMemTags_packets(self):
self.check_tag_read("{:x},10:".format(buf_address), "E03")
# Types we don't support
self.check_tag_read("{:x},10:FF".format(buf_address), "E01")
+ # Types can also be negative, -1 in this case.
+ # So this is E01 for not supported, instead of E03 for invalid formatting.
+ self.check_tag_read("{:x},10:FFFFFFFF".format(buf_address), "E01")
# (even if the length of the read is zero)
self.check_tag_read("{:x},0:FF".format(buf_address), "E01")
- self.check_tag_read("{:x},10:-1".format(buf_address), "E01")
- self.check_tag_read("{:x},10:+20".format(buf_address), "E01")
# Invalid type format
self.check_tag_read("{:x},10:cat".format(buf_address), "E03")
self.check_tag_read("{:x},10:?11".format(buf_address), "E03")
+ # Type is signed but in packet as raw bytes, no +/-.
+ self.check_tag_read("{:x},10:-1".format(buf_address), "E03")
+ self.check_tag_read("{:x},10:+20".format(buf_address), "E03")
+ # We do use a uint64_t for unpacking but that's just an implementation
+ # detail. Any value > 32 bit is invalid.
+ self.check_tag_read("{:x},10:123412341".format(buf_address), "E03")
# Valid packets
diff --git a/lldb/unittests/Process/gdb-remote/GDBRemoteCommunicationClientTest.cpp b/lldb/unittests/Process/gdb-remote/GDBRemoteCommunicationClientTest.cpp
index 37ed0f7ded288..d15b85204b555 100644
--- a/lldb/unittests/Process/gdb-remote/GDBRemoteCommunicationClientTest.cpp
+++ b/lldb/unittests/Process/gdb-remote/GDBRemoteCommunicationClientTest.cpp
@@ -470,19 +470,18 @@ TEST_F(GDBRemoteCommunicationClientTest, GetQOffsets) {
static void
check_qmemtags(TestClient &client, MockServer &server, size_t read_len,
- const char *packet, llvm::StringRef response,
+ int32_t type, const char *packet, llvm::StringRef response,
llvm::Optional<std::vector<uint8_t>> expected_tag_data) {
- const auto &ReadMemoryTags = [&](size_t len, const char *packet,
- llvm::StringRef response) {
+ const auto &ReadMemoryTags = [&]() {
std::future<DataBufferSP> result = std::async(std::launch::async, [&] {
- return client.ReadMemoryTags(0xDEF0, read_len, 1);
+ return client.ReadMemoryTags(0xDEF0, read_len, type);
});
HandlePacket(server, packet, response);
return result.get();
};
- auto result = ReadMemoryTags(0, packet, response);
+ auto result = ReadMemoryTags();
if (expected_tag_data) {
ASSERT_TRUE(result);
llvm::ArrayRef<uint8_t> expected(*expected_tag_data);
@@ -495,41 +494,53 @@ check_qmemtags(TestClient &client, MockServer &server, size_t read_len,
TEST_F(GDBRemoteCommunicationClientTest, ReadMemoryTags) {
// Zero length reads are valid
- check_qmemtags(client, server, 0, "qMemTags:def0,0:1", "m",
+ check_qmemtags(client, server, 0, 1, "qMemTags:def0,0:1", "m",
std::vector<uint8_t>{});
+ // Type can be negative. Put into the packet as the raw bytes
+ // (as opposed to a literal -1)
+ check_qmemtags(client, server, 0, -1, "qMemTags:def0,0:ffffffff", "m",
+ std::vector<uint8_t>{});
+ check_qmemtags(client, server, 0, std::numeric_limits<int32_t>::min(),
+ "qMemTags:def0,0:80000000", "m", std::vector<uint8_t>{});
+ check_qmemtags(client, server, 0, std::numeric_limits<int32_t>::max(),
+ "qMemTags:def0,0:7fffffff", "m", std::vector<uint8_t>{});
+
// The client layer does not check the length of the received data.
// All we need is the "m" and for the decode to use all of the chars
- check_qmemtags(client, server, 32, "qMemTags:def0,20:1", "m09",
+ check_qmemtags(client, server, 32, 2, "qMemTags:def0,20:2", "m09",
std::vector<uint8_t>{0x9});
// Zero length response is fine as long as the "m" is present
- check_qmemtags(client, server, 0, "qMemTags:def0,0:1", "m",
+ check_qmemtags(client, server, 0, 0x34, "qMemTags:def0,0:34", "m",
std::vector<uint8_t>{});
// Normal responses
- check_qmemtags(client, server, 16, "qMemTags:def0,10:1", "m66",
+ check_qmemtags(client, server, 16, 1, "qMemTags:def0,10:1", "m66",
std::vector<uint8_t>{0x66});
- check_qmemtags(client, server, 32, "qMemTags:def0,20:1", "m0102",
+ check_qmemtags(client, server, 32, 1, "qMemTags:def0,20:1", "m0102",
std::vector<uint8_t>{0x1, 0x2});
// Empty response is an error
- check_qmemtags(client, server, 17, "qMemTags:def0,11:1", "", llvm::None);
+ check_qmemtags(client, server, 17, 1, "qMemTags:def0,11:1", "", llvm::None);
// Usual error response
- check_qmemtags(client, server, 17, "qMemTags:def0,11:1", "E01", llvm::None);
+ check_qmemtags(client, server, 17, 1, "qMemTags:def0,11:1", "E01",
+ llvm::None);
// Leading m missing
- check_qmemtags(client, server, 17, "qMemTags:def0,11:1", "01", llvm::None);
+ check_qmemtags(client, server, 17, 1, "qMemTags:def0,11:1", "01", llvm::None);
// Anything other than m is an error
- check_qmemtags(client, server, 17, "qMemTags:def0,11:1", "z01", llvm::None);
+ check_qmemtags(client, server, 17, 1, "qMemTags:def0,11:1", "z01",
+ llvm::None);
// Decoding tag data doesn't use all the chars in the packet
- check_qmemtags(client, server, 32, "qMemTags:def0,20:1", "m09zz", llvm::None);
+ check_qmemtags(client, server, 32, 1, "qMemTags:def0,20:1", "m09zz",
+ llvm::None);
// Data that is not hex bytes
- check_qmemtags(client, server, 32, "qMemTags:def0,20:1", "mhello",
+ check_qmemtags(client, server, 32, 1, "qMemTags:def0,20:1", "mhello",
llvm::None);
// Data is not a complete hex char
- check_qmemtags(client, server, 32, "qMemTags:def0,20:1", "m9", llvm::None);
+ check_qmemtags(client, server, 32, 1, "qMemTags:def0,20:1", "m9", llvm::None);
// Data has a trailing hex char
- check_qmemtags(client, server, 32, "qMemTags:def0,20:1", "m01020",
+ check_qmemtags(client, server, 32, 1, "qMemTags:def0,20:1", "m01020",
llvm::None);
}
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