support file-based credentials
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This commit is contained in:
Emil Lerch 2022-01-31 09:01:30 -08:00
parent 6229644bca
commit b53cbc3ea5
Signed by: lobo
GPG Key ID: A7B62D657EF764F8
2 changed files with 364 additions and 2 deletions

View File

@ -8,9 +8,27 @@ const std = @import("std");
const builtin = @import("builtin");
const auth = @import("aws_authentication.zig");
pub fn getCredentials(allocator: std.mem.Allocator) !auth.Credentials {
const log = std.log.scoped(.aws_credentials);
pub const Profile = struct {
/// Credential file. Defaults to AWS_SHARED_CREDENTIALS_FILE or ~/.aws/credentials
credential_file: ?[]const u8 = null,
/// Config file. Defaults to AWS_CONFIG_FILE or ~/.aws/config
config_file: ?[]const u8 = null,
/// Config file. Defaults to AWS_PROFILE or default
profile_name: ?[]const u8 = null,
};
pub const Options = struct {
profile: Profile = .{},
};
pub fn getCredentials(allocator: std.mem.Allocator, options: Options) !auth.Credentials {
if (try getEnvironmentCredentials(allocator)) |cred| return cred;
// TODO: 2-5
// Note that boto and Java disagree on where this fits in the order
if (try getWebIdentityToken(allocator)) |cred| return cred;
if (try getProfileCredentials(allocator, options.profile)) |cred| return cred;
return error.NotImplemented;
}
@ -34,3 +52,346 @@ fn getEnvironmentVariable(allocator: std.mem.Allocator, key: []const u8) !?[]con
else => return e,
};
}
fn getWebIdentityToken(allocator: std.mem.Allocator) !?auth.Credentials {
_ = allocator;
// This API does not require signing. We can just use zfetch to
// shoot a raw request over.
// https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html
// https://github.com/boto/boto3/blob/85b975af30c408f93b654a21930218edd58336ad/docs/source/guide/credentials.rst#assume-role-with-web-identity-provider
// https://github.com/aws/aws-sdk-java-v2/blob/master/core/auth/src/main/java/software/amazon/awssdk/auth/credentials/WebIdentityTokenFileCredentialsProvider.java
// TODO: implement
return null;
}
fn getProfileCredentials(allocator: std.mem.Allocator, options: Profile) !?auth.Credentials {
var default_path: ?[]const u8 = null;
defer if (default_path) |p| allocator.free(p);
const creds_file_path = try filePath(
allocator,
options.credential_file,
"AWS_SHARED_CREDENTIALS_FILE",
default_path,
"credentials",
);
defer allocator.free(creds_file_path.evaluated_path);
default_path = default_path orelse creds_file_path.home;
const config_file_path = try filePath(
allocator,
options.credential_file,
"AWS_SHARED_CREDENTIALS_FILE",
default_path,
"config",
);
defer allocator.free(config_file_path.evaluated_path);
default_path = default_path orelse config_file_path.home;
// Get active profile
const profile = (try getEnvironmentVariable(allocator, "AWS_PROFILE")) orelse
try allocator.dupe(u8, "default");
defer allocator.free(profile);
log.debug("Looking for file credentials using profile '{s}'", .{profile});
log.debug("Checking credentials file: {s}", .{creds_file_path.evaluated_path});
const credentials_file = std.fs.openFileAbsolute(creds_file_path.evaluated_path, .{}) catch null;
defer if (credentials_file) |f| f.close();
// It's much more likely that we'll find credentials in the credentials file
// so we'll try that first
const creds_file_creds = try credsForFile(allocator, credentials_file, profile);
var conf_file_creds = PartialCredentials{};
if (creds_file_creds.access_key == null or creds_file_creds.secret_key == null) {
log.debug("Checking config file: {s}", .{config_file_path.evaluated_path});
const config_file = std.fs.openFileAbsolute(creds_file_path.evaluated_path, .{}) catch null;
defer if (config_file) |f| f.close();
conf_file_creds = try credsForFile(allocator, config_file, profile);
}
const access_key = keyFrom(allocator, creds_file_creds.access_key, conf_file_creds.access_key);
const secret_key = keyFrom(allocator, creds_file_creds.secret_key, conf_file_creds.secret_key);
defer if (secret_key) |k| allocator.free(k);
if (access_key == null or secret_key == null) {
const partial = access_key != null or secret_key != null;
if (partial) {
log.warn("Could not find credentials in file (partial creds detected)", .{});
} else {
log.info("Could not find credentials in file", .{});
}
if (access_key) |k| allocator.free(k);
return null;
}
log.debug("Got full credentials from filesystem. Access key: {s}", .{access_key.?});
return auth.Credentials.init(
allocator,
access_key.?,
try allocator.dupe(u8, secret_key.?),
null,
);
}
fn keyFrom(allocator: std.mem.Allocator, priority_1: ?[]const u8, priority_2: ?[]const u8) ?[]const u8 {
if (priority_1) |p1| {
if (priority_2) |p2| allocator.free(p2);
return p1;
}
return priority_2;
}
// We could conceivably find different portions of the creds in different
// files, so let's be super-loose here
const PartialCredentials = struct {
access_key: ?[]const u8 = null,
secret_key: ?[]const u8 = null,
};
fn credsForFile(allocator: std.mem.Allocator, file: ?std.fs.File, profile: []const u8) !PartialCredentials {
if (file == null) return PartialCredentials{};
const text = try file.?.readToEndAlloc(allocator, std.math.maxInt(usize));
defer allocator.free(text);
const partial_creds = try credsForText(text, profile);
var ak: ?[]const u8 = null;
if (partial_creds.access_key) |k|
ak = try allocator.dupe(u8, k);
var sk: ?[]const u8 = null;
if (partial_creds.secret_key) |k|
sk = try allocator.dupe(u8, k);
return PartialCredentials{
.access_key = ak,
.secret_key = sk,
};
}
const LineIterator = struct {
text: []const u8,
inx: usize = 0,
const Self = @This();
pub fn init(text: []const u8) Self {
return .{
.text = text,
.inx = 0,
};
}
pub fn next(self: *Self) ?[]const u8 {
if (self.inx >= self.text.len) return null;
var current = self.inx;
var start = self.inx;
for (self.text[self.inx..]) |c, i| {
if (c == '\n') {
// log.debug("got \\n: {d}", .{i});
current += i + 1;
break;
}
}
// log.debug("{d}:{d}", .{ current, self.inx });
if (current != self.inx) {
self.inx = current;
} else { // no \n found
self.inx = self.text.len + 1; // add one to capture the last char in return
}
return self.text[start .. self.inx - 1];
}
};
fn credsForText(text: []const u8, profile: []const u8) !PartialCredentials {
var lines = LineIterator.init(text);
var is_in_profile = false;
var was_in_profile = false;
var done = false;
var creds: [2]?[]const u8 = [_]?[]const u8{ null, null };
while (lines.next()) |line| {
// log.debug("line: {s}", .{line});
var section_start: ?usize = 0;
for (line) |c, i| {
switch (c) {
'#' => break,
'[' => section_start = i + 1,
']' => {
if (section_start) |s| {
const current_section = line[s..i];
log.debug("got section: {s}", .{current_section});
is_in_profile = std.ascii.eqlIgnoreCase(current_section, profile);
if (was_in_profile and !is_in_profile) {
done = true;
break;
}
was_in_profile = is_in_profile;
break; // got what we need from this line
}
},
'=' => {
if (!is_in_profile) continue;
const key = std.mem.trim(u8, line[0..i], " \t"); // other whitespace we care about?
log.debug("got key: {s}", .{key});
for (&[_][]const u8{
"aws_access_key_id",
"aws_secret_access_key",
}) |needle, inx| {
if (std.ascii.eqlIgnoreCase(key, needle)) {
// TODO: Trim this out
creds[inx] = trim(line[i + 1 ..]);
}
}
},
else => {},
}
}
if (done) {
log.debug("no longer in target section: bailing", .{});
break;
}
}
log.debug("done parsing text", .{});
return PartialCredentials{
.access_key = creds[0],
.secret_key = creds[1],
};
}
fn trim(text: []const u8) []const u8 {
// " myval # yo";
var start: ?usize = null;
var end: ?usize = null;
for (text) |c, i| switch (c) {
' ', '\t' => {},
'#' => return trimmed(text, start, end),
else => {
if (start == null) start = i;
end = i + 1;
},
};
return trimmed(text, start, end);
}
fn trimmed(text: []const u8, start: ?usize, end: ?usize) []const u8 {
if (start == null) return "";
if (end == null) return text[start.?..];
return text[start.?..end.?];
}
fn filePath(
allocator: std.mem.Allocator,
specified_path: ?[]const u8,
env_var_name: []const u8,
config_dir: ?[]const u8,
config_file_name: []const u8,
) !EvaluatedPath {
if (specified_path) |p| return EvaluatedPath{ .evaluated_path = try allocator.dupe(u8, p) };
// Not specified. Check environment variable, otherwise, hard coded default
if (try getEnvironmentVariable(allocator, env_var_name)) |v| return EvaluatedPath{ .evaluated_path = v };
// Not in environment variable either. Go fish
return try getDefaultPath(allocator, config_dir, ".aws", config_file_name);
}
const EvaluatedPath = struct {
home: ?[]const u8 = null,
evaluated_path: []const u8,
};
fn getDefaultPath(allocator: std.mem.Allocator, home_dir: ?[]const u8, dir: []const u8, file: []const u8) !EvaluatedPath {
var home = home_dir orelse try getHomeDir(allocator);
log.debug("Home directory: {s}", .{home});
const rc = try std.fs.path.join(allocator, &[_][]const u8{ home, dir, file });
log.debug("Path evaluated as: {s}", .{rc});
return EvaluatedPath{ .home = home, .evaluated_path = rc };
}
fn getHomeDir(allocator: std.mem.Allocator) ![]const u8 {
switch (builtin.os.tag) {
.windows => {
var dir_path_ptr: [*:0]u16 = undefined;
// https://docs.microsoft.com/en-us/windows/win32/shell/knownfolderid
const FOLDERID_Profile = std.os.windows.GUID.parse("{5E6C858F-0E22-4760-9AFE-EA3317B67173}");
switch (std.os.windows.shell32.SHGetKnownFolderPath(
&FOLDERID_Profile,
std.os.windows.KF_FLAG_CREATE,
null,
&dir_path_ptr,
)) {
std.os.windows.S_OK => {
defer std.os.windows.ole32.CoTaskMemFree(@ptrCast(*anyopaque, dir_path_ptr));
const global_dir = std.unicode.utf16leToUtf8Alloc(allocator, std.mem.sliceTo(dir_path_ptr, 0)) catch |err| switch (err) {
error.UnexpectedSecondSurrogateHalf => return error.HomeDirUnavailable,
error.ExpectedSecondSurrogateHalf => return error.HomeDirUnavailable,
error.DanglingSurrogateHalf => return error.HomeDirUnavailable,
error.OutOfMemory => return error.OutOfMemory,
};
return global_dir;
// defer allocator.free(global_dir);
},
std.os.windows.E_OUTOFMEMORY => return error.OutOfMemory,
else => return error.HomeDirUnavailable,
}
},
.macos, .linux, .freebsd, .netbsd, .dragonfly, .openbsd, .solaris => {
const home_dir = std.os.getenv("HOME") orelse {
// TODO look in /etc/passwd
return error.HomeDirUnavailable;
};
return allocator.dupe(u8, home_dir);
},
// Code from https://github.com/ziglang/zig/blob/9f9f215305389c08a21730859982b68bf2681932/lib/std/fs/get_app_data_dir.zig
// be_user_settings magic number is probably different for home directory
// .haiku => {
// var dir_path_ptr: [*:0]u8 = undefined;
// // TODO look into directory_which
// const be_user_settings = 0xbbe;
// const rc = os.system.find_directory(be_user_settings, -1, true, dir_path_ptr, 1);
// const settings_dir = try allocator.dupeZ(u8, mem.sliceTo(dir_path_ptr, 0));
// defer allocator.free(settings_dir);
// switch (rc) {
// 0 => return fs.path.join(allocator, &[_][]const u8{ settings_dir, appname }),
// else => return error.AppDataDirUnavailable,
// }
// },
else => @compileError("Unsupported OS"),
}
}
test "filePath" {
const allocator = std.testing.allocator;
std.testing.log_level = .debug;
log.debug("\n", .{});
const path = try filePath(allocator, null, "NOTHING", null, "hello");
defer allocator.free(path.evaluated_path);
defer allocator.free(path.home.?);
try std.testing.expect(path.evaluated_path.len > 10);
try std.testing.expectEqualStrings("hello", path.evaluated_path[path.evaluated_path.len - 5 ..]);
try std.testing.expect(path.home != null);
}
test "ini to creds" {
std.testing.log_level = .debug;
log.debug("\n", .{});
const partial_creds = try credsForText(
\\
\\# Amazon Web Services Credentials File used by AWS CLI, SDKs, and tools
\\# This file was created by the AWS Toolkit for Visual Studio Code extension.
\\#
\\# Your AWS credentials are represented by access keys associated with IAM users.
\\# For information about how to create and manage AWS access keys for a user, see:
\\# https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html
\\#
\\# This credential file can store multiple access keys by placing each one in a
\\# named "profile". For information about how to change the access keys in a
\\# profile or to add a new profile with a different access key, see:
\\# https://docs.aws.amazon.com/cli/latest/userguide/cli-config-files.html
\\#
\\[other_section]
\\access_key_id = NOTYOURACCESSKEY
\\
\\ [default]
\\ # The access key and secret key pair identify your account and grant access to AWS.
\\aws_access_key_id = AKIDEXAMPLE # access key
\\
\\[another_section]
\\access_key_id = NOTYOURACCESSKEYEITHER
, "default");
try std.testing.expect(partial_creds.access_key != null);
try std.testing.expectEqualStrings("AKIDEXAMPLE", partial_creds.access_key.?);
try std.testing.expect(partial_creds.secret_key == null);
}

View File

@ -97,7 +97,8 @@ pub const AwsHttp = struct {
const endpoint = try regionSubDomain(self.allocator, service, options.region, options.dualstack);
defer endpoint.deinit();
log.debug("Calling endpoint {s}", .{endpoint.uri});
const creds = try credentials.getCredentials(self.allocator);
// TODO: Should we allow customization here?
const creds = try credentials.getCredentials(self.allocator, .{});
defer creds.deinit();
const signing_config: signing.Config = .{
.region = options.region,