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Merge "Add checks to ensure only the ART memfd file is whitelisted."

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This commit is contained in:
Nicolas Geoffray
2019-10-30 08:24:37 +00:00
committed by Gerrit Code Review
parent d7f38d742b abbd4a7aa0
commit 555ffd1c0c
1 changed files with 18 additions and 6 deletions
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24
core/jni/fd_utils.cpp
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@@ -59,8 +59,8 @@ FileDescriptorWhitelist* FileDescriptorWhitelist::Get() {
return instance_; return instance_;
} }
static bool IsMemfd(const std::string& path) { static bool IsArtMemfd(const std::string& path) {
return android::base::StartsWith(path, "/memfd:"); return android::base::StartsWith(path, "/memfd:/boot-image-methods.art");
} }
bool FileDescriptorWhitelist::IsAllowed(const std::string& path) const { bool FileDescriptorWhitelist::IsAllowed(const std::string& path) const {
@@ -91,8 +91,8 @@ bool FileDescriptorWhitelist::IsAllowed(const std::string& path) const {
return true; return true;
} }
// In-memory files created through memfd_create are allowed. // the in-memory file created by ART through memfd_create is allowed.
if (IsMemfd(path)) { if (IsArtMemfd(path)) {
return true; return true;
} }
@@ -321,8 +321,8 @@ void FileDescriptorInfo::ReopenOrDetach(fail_fn_t fail_fn) const {
return DetachSocket(fail_fn); return DetachSocket(fail_fn);
} }
// Children can directly use in-memory files created through memfd_create. // Children can directly use the in-memory file created by ART through memfd_create.
if (IsMemfd(file_path)) { if (IsArtMemfd(file_path)) {
return; return;
} }
@@ -545,6 +545,10 @@ FileDescriptorTable::FileDescriptorTable(
} }
void FileDescriptorTable::RestatInternal(std::set<int>& open_fds, fail_fn_t fail_fn) { void FileDescriptorTable::RestatInternal(std::set<int>& open_fds, fail_fn_t fail_fn) {
// ART creates a file through memfd for optimization purposes. We make sure
// there is at most one being created.
bool art_memfd_seen = false;
// Iterate through the list of file descriptors we've already recorded // Iterate through the list of file descriptors we've already recorded
// and check whether : // and check whether :
// //
@@ -577,6 +581,14 @@ void FileDescriptorTable::RestatInternal(std::set<int>& open_fds, fail_fn_t fail
// FD. // FD.
} }
if (IsArtMemfd(it->second->file_path)) {
if (art_memfd_seen) {
fail_fn("ART fd already seen: " + it->second->file_path);
} else {
art_memfd_seen = true;
}
}
++it; ++it;
// Finally, remove the FD from the set of open_fds. We do this last because // Finally, remove the FD from the set of open_fds. We do this last because