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Fix memory safety vulnerabilities (OOB Read & Integer Overflow) #86

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Fix memory safety vulnerabilities (OOB Read & Integer Overflow) #86

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19 changes: 10 additions & 9 deletions robots.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,7 @@ class RobotsMatchStrategy {
absl::string_view path, absl::string_view pattern) {
const size_t pathlen = path.length();
absl::FixedArray<size_t> pos(pathlen + 1);
int numpos;
size_t numpos;

// The pos[] array holds a sorted list of indexes of 'path', with length
// 'numpos'. At the start and end of each iteration of the main loop below,
Expand All @@ -94,17 +94,17 @@ class RobotsMatchStrategy {

for (auto pat = pattern.begin(); pat != pattern.end(); ++pat) {
if (*pat == '$' && pat + 1 == pattern.end()) {
return (pos[numpos - 1] == pathlen);
return (numpos > 0 && pos[numpos - 1] == pathlen);
}
if (*pat == '*') {
numpos = pathlen - pos[0] + 1;
for (int i = 1; i < numpos; i++) {
for (size_t i = 1; i < numpos; i++) {
pos[i] = pos[i-1] + 1;
}
} else {
// Includes '$' when not at end of pattern.
int newnumpos = 0;
for (int i = 0; i < numpos; i++) {
size_t newnumpos = 0;
for (size_t i = 0; i < numpos; i++) {
if (pos[i] < pathlen && path[pos[i]] == *pat) {
pos[newnumpos++] = pos[i] + 1;
}
Expand Down Expand Up @@ -602,11 +602,12 @@ void RobotsMatcher::HandleRobotsStart() {
/*static*/ absl::string_view RobotsMatcher::ExtractUserAgent(
absl::string_view user_agent) {
// Allowed characters in user-agent are [a-zA-Z_-].
const char* end = user_agent.data();
while (absl::ascii_isalpha(*end) || *end == '-' || *end == '_') {
++end;
const char* p = user_agent.data();
const char* end = p + user_agent.length();
while (p < end && (absl::ascii_isalpha(*p) || *p == '-' || *p == '_')) {
++p;
}
return user_agent.substr(0, end - user_agent.data());
return user_agent.substr(0, p - user_agent.data());
}

/*static*/ bool RobotsMatcher::IsValidUserAgentToObey(
Expand Down