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Merge pull request #14222 from lovesegfault/curl-based-s3-fix-race

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fix(libstore): fix race condition in AWS credential provider caching
This commit is contained in:
John Ericson
2025-10-12 22:07:10 +00:00
committed by GitHub
parent 4f585dedbe f0e1f65260
commit f77094715f
1 changed files with 47 additions and 38 deletions
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43
src/libstore/aws-creds.cc
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@@ -118,11 +118,14 @@ AwsCredentials getAwsCredentials(const std::string & profile)
// Get or create credential provider with caching
std::shared_ptr<Aws::Crt::Auth::ICredentialsProvider> provider;
// Try to find existing provider
credentialProviderCache.visit(profile, [&](const auto & pair) { provider = pair.second; });
if (!provider) {
// Create new provider if not found
// Use try_emplace_and_cvisit for atomic get-or-create
// This prevents race conditions where multiple threads create providers
credentialProviderCache.try_emplace_and_cvisit(
profile,
nullptr, // Placeholder - will be replaced in f1 before any thread can see it
[&](auto & kv) {
// f1: Called atomically during insertion with non-const reference
// Other threads are blocked until we finish, so nullptr is never visible
debug(
"[pid=%d] creating new AWS credential provider for profile '%s'",
getpid(),
@@ -134,32 +137,38 @@ AwsCredentials getAwsCredentials(const std::string & profile)
if (profile.empty()) {
Aws::Crt::Auth::CredentialsProviderChainDefaultConfig config;
config.Bootstrap = Aws::Crt::ApiHandle::GetOrCreateStaticDefaultClientBootstrap();
provider = Aws::Crt::Auth::CredentialsProvider::CreateCredentialsProviderChainDefault(config);
kv.second = Aws::Crt::Auth::CredentialsProvider::CreateCredentialsProviderChainDefault(config);
} else {
Aws::Crt::Auth::CredentialsProviderProfileConfig config;
config.Bootstrap = Aws::Crt::ApiHandle::GetOrCreateStaticDefaultClientBootstrap();
// This is safe because the underlying C library will copy this string
// c.f. https://github.com/awslabs/aws-c-auth/blob/main/source/credentials_provider_profile.c#L220
config.ProfileNameOverride = Aws::Crt::ByteCursorFromCString(profile.c_str());
provider = Aws::Crt::Auth::CredentialsProvider::CreateCredentialsProviderProfile(config);
}
} catch (Error & e) {
e.addTrace(
{},
"while creating AWS credentials provider for %s",
profile.empty() ? "default profile" : fmt("profile '%s'", profile));
throw;
kv.second = Aws::Crt::Auth::CredentialsProvider::CreateCredentialsProviderProfile(config);
}
if (!provider) {
if (!kv.second) {
throw AwsAuthError(
"Failed to create AWS credentials provider for %s",
profile.empty() ? "default profile" : fmt("profile '%s'", profile));
}
// Insert into cache (try_emplace is thread-safe and won't overwrite if another thread added it)
credentialProviderCache.try_emplace(profile, provider);
provider = kv.second;
} catch (Error & e) {
// Exception during creation - remove the entry to allow retry
credentialProviderCache.erase(profile);
e.addTrace({}, "for AWS profile: %s", profile.empty() ? "(default)" : profile);
throw;
} catch (...) {
// Non-Error exception - still need to clean up
credentialProviderCache.erase(profile);
throw;
}
},
[&](const auto & kv) {
// f2: Called if key already exists (const reference)
provider = kv.second;
});
return getCredentialsFromProvider(provider);
}