From 2b5d5cca33546bf83f12ef67e8cc63409a117bc6 Mon Sep 17 00:00:00 2001 From: Jason Molenda Date: Wed, 3 Sep 2025 16:31:42 -0700 Subject: [PATCH] [lldb][debugserver] Max response size for qSpeedTest (#156099) The qSpeedTest packet is used for experiments to determine the optimal packet size for a given communication medium, e.g. to transfer 10MB of memory, is it faster to send a hundred 100KB packets or ten 1MB packets. It creates a packet of the requested size in a stack allocation, but is not checking that its buffer is large enough for the requested size. Change this allocation to be on heap, and impose a maximum size that can be tested (4MB, for now). rdar://158630250 (cherry picked from commit ac8e7be5fbd11f731ffc81bf3bbae50a5a4d83de) --- lldb/tools/debugserver/source/RNBRemote.cpp | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/lldb/tools/debugserver/source/RNBRemote.cpp b/lldb/tools/debugserver/source/RNBRemote.cpp index 3247e96424ed5..673328a6bd393 100644 --- a/lldb/tools/debugserver/source/RNBRemote.cpp +++ b/lldb/tools/debugserver/source/RNBRemote.cpp @@ -4519,12 +4519,12 @@ rnb_err_t RNBRemote::HandlePacket_qSpeedTest(const char *p) { return HandlePacket_ILLFORMED( __FILE__, __LINE__, p, "Didn't find response_size value at right offset"); - else if (*end == ';') { - static char g_data[4 * 1024 * 1024 + 16]; - strcpy(g_data, "data:"); - memset(g_data + 5, 'a', response_size); - g_data[response_size + 5] = '\0'; - return SendPacket(g_data); + else if (*end == ';' && response_size < (4 * 1024 * 1024)) { + std::vector buf(response_size + 6, 'a'); + memcpy(buf.data(), "data:", 5); + buf[buf.size() - 1] = '\0'; + rnb_err_t return_value = SendPacket(buf.data()); + return return_value; } else { return SendErrorPacket("E79"); }