UNLOZE/sm-ext-accelerator-2023
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Read auxv from proc rather than the stack

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This commit is contained in:
Asher Baker 2019-01-12 01:33:10 +00:00
parent 3582376f35
commit 2d4ffc703b
2 changed files with 62 additions and 44 deletions
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53
extension/extension.cpp
View File

@ -490,29 +490,38 @@ class UploadThread: public IThread
std::string vdsoOutputPath = "";
if (debugFile == "linux-gate.so") {
char vdsoOutputPathBuffer[512];
g_pSM->BuildPath(Path_SM, vdsoOutputPathBuffer, sizeof(vdsoOutputPathBuffer), "data/dumps/linux-gate.so");
vdsoOutputPath = vdsoOutputPathBuffer;
int auxvStart = 0;
while (environ[auxvStart++] != nullptr);
struct {
int id;
void *value;
} *auxvEntry = (decltype(auxvEntry))&environ[auxvStart];
for (int auxvIndex = 0; true; ++auxvIndex) {
if (auxvEntry[auxvIndex].id == 0) break;
if (auxvEntry[auxvIndex].id != 33) continue; // AT_SYSINFO_EHDR
Elf32_Ehdr *vdsoHdr = (Elf32_Ehdr *)auxvEntry[auxvIndex].value;
auto vdsoSize = vdsoHdr->e_shoff + (vdsoHdr->e_shentsize * vdsoHdr->e_shnum);
void *vdsoBuffer = malloc(vdsoSize);
memcpy(vdsoBuffer, vdsoHdr, vdsoSize);
FILE *vdsoFile = fopen(vdsoOutputPath.c_str(), "wb");
if (vdsoFile) {
fwrite(vdsoBuffer, 1, vdsoSize, vdsoFile);
fclose(vdsoFile);
debugFile = vdsoOutputPath;
FILE *auxvFile = fopen("/proc/self/auxv", "rb");
if (auxvFile) {
char vdsoOutputPathBuffer[512];
g_pSM->BuildPath(Path_SM, vdsoOutputPathBuffer, sizeof(vdsoOutputPathBuffer), "data/dumps/linux-gate.so");
vdsoOutputPath = vdsoOutputPathBuffer;
while (!feof(auxvFile)) {
int auxvEntryId = 0;
fread(&auxvEntryId, sizeof(auxvEntryId), 1, auxvFile);
long auxvEntryValue = 0;
fread(&auxvEntryValue, sizeof(auxvEntryValue), 1, auxvFile);
if (auxvEntryId == 0) break;
if (auxvEntryId != 33) continue; // AT_SYSINFO_EHDR
Elf32_Ehdr *vdsoHdr = (Elf32_Ehdr *)auxvEntryValue;
auto vdsoSize = vdsoHdr->e_shoff + (vdsoHdr->e_shentsize * vdsoHdr->e_shnum);
void *vdsoBuffer = malloc(vdsoSize);
memcpy(vdsoBuffer, vdsoHdr, vdsoSize);
FILE *vdsoFile = fopen(vdsoOutputPath.c_str(), "wb");
if (vdsoFile) {
fwrite(vdsoBuffer, 1, vdsoSize, vdsoFile);
fclose(vdsoFile);
debugFile = vdsoOutputPath;
}
free(vdsoBuffer);
break;
}
free(vdsoBuffer);
fclose(auxvFile);
}
}

53
test/test.cpp
View File

@ -240,30 +240,39 @@ int main(int argc, char *argv[])
std::string vdsoOutputPath = "";
if (debugFile == "linux-gate.so") {
auto workingDir = getcwd(nullptr, 0);
vdsoOutputPath = workingDir + std::string("/linux-gate.so");
int auxvStart = 0;
while (environ[auxvStart++] != nullptr);
struct {
int id;
void *value;
} *auxvEntry = (decltype(auxvEntry))&environ[auxvStart];
for (int auxvIndex = 0; true; ++auxvIndex) {
if (auxvEntry[auxvIndex].id == 0) break;
if (auxvEntry[auxvIndex].id != 33) continue; // AT_SYSINFO_EHDR
Elf32_Ehdr *vdsoHdr = (Elf32_Ehdr *)auxvEntry[auxvIndex].value;
auto vdsoSize = vdsoHdr->e_shoff + (vdsoHdr->e_shentsize * vdsoHdr->e_shnum);
void *vdsoBuffer = malloc(vdsoSize);
memcpy(vdsoBuffer, vdsoHdr, vdsoSize);
FILE *vdsoFile = fopen(vdsoOutputPath.c_str(), "wb");
if (vdsoFile) {
fwrite(vdsoBuffer, 1, vdsoSize, vdsoFile);
fclose(vdsoFile);
debugFile = vdsoOutputPath;
FILE *auxvFile = fopen("/proc/self/auxv", "rb");
if (auxvFile) {
auto workingDir = getcwd(nullptr, 0);
vdsoOutputPath = workingDir + std::string("/linux-gate.so");
free(workingDir);
while (!feof(auxvFile)) {
int auxvEntryId = 0;
fread(&auxvEntryId, sizeof(auxvEntryId), 1, auxvFile);
long auxvEntryValue = 0;
fread(&auxvEntryValue, sizeof(auxvEntryValue), 1, auxvFile);
if (auxvEntryId == 0) break;
if (auxvEntryId != 33) continue; // AT_SYSINFO_EHDR
Elf32_Ehdr *vdsoHdr = (Elf32_Ehdr *)auxvEntryValue;
auto vdsoSize = vdsoHdr->e_shoff + (vdsoHdr->e_shentsize * vdsoHdr->e_shnum);
void *vdsoBuffer = malloc(vdsoSize);
memcpy(vdsoBuffer, vdsoHdr, vdsoSize);
FILE *vdsoFile = fopen(vdsoOutputPath.c_str(), "wb");
if (vdsoFile) {
fwrite(vdsoBuffer, 1, vdsoSize, vdsoFile);
fclose(vdsoFile);
debugFile = vdsoOutputPath;
}
free(vdsoBuffer);
break;
}
free(vdsoBuffer);
fclose(auxvFile);
}
free(workingDir);
}
if (debugFile[0] != '/') {