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Protect base64 encoding buffers #2447

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Protect base64 encoding buffers #2447

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c402339
tests: characterize extacl base64 stack buffer overflow
kinkie Jun 15, 2026
2125dc5
icap: fix extacl credential buffer overflow in makeRequestHeaders
kinkie Jun 17, 2026
3d1055f
http: fix extacl credential buffer overflows in httpFixupAuthentication
kinkie Jun 17, 2026
1c410dc
Merge remote-tracking branch 'upstream/master' into fix-base64encode
kinkie Jun 19, 2026
f6c053e
Apply aaa
kinkie Jun 20, 2026
ef95154
Remove test harness
kinkie Jun 20, 2026
d7fa149
Use TextException
kinkie Jun 20, 2026
5044dd7
Update src/adaptation/icap/ModXact.cc
kinkie Jul 5, 2026
9c81411
Merge branch 'master' into fix-base64encode
kinkie Jul 7, 2026
c037cd4
define -> constexpr auto
kinkie Jul 7, 2026
8503055
Add field size checks
kinkie Jul 7, 2026
8dff603
Fix Assure() position and include header
kinkie Jul 11, 2026
da6bc4a
Revert broken changes to ModXact.cc
kinkie Jul 11, 2026
987250e
add missing include
kinkie Jul 11, 2026
eb5e533
Accept review suggestion
kinkie Jul 11, 2026
8305b74
add size guard to SSP_MakeChallenge
kinkie Jul 11, 2026
bc1955f
revert BUF_SZ change
kinkie Jul 11, 2026
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14 changes: 11 additions & 3 deletions src/adaptation/icap/ModXact.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1399,12 +1399,20 @@ void Adaptation::Icap::ModXact::makeRequestHeaders(MemBuf &buf)
String vh=virgin.header->header.getById(Http::HdrType::PROXY_AUTHORIZATION);
buf.appendf("Proxy-Authorization: " SQUIDSTRINGPH "\r\n", SQUIDSTRINGPRINT(vh));
} else if (request->extacl_user.size() > 0 && request->extacl_passwd.size() > 0) {
const auto userLen = request->extacl_user.size();
const auto passwdLen = request->extacl_passwd.size();
// +1 for the ':' separator between user and passwd
const auto plainLen = userLen + 1 + passwdLen;
if (plainLen > MAX_LOGIN_SZ)
throw TextException("extacl credentials too long for Proxy-Authorization", Here());
// plainLen <= MAX_LOGIN_SZ, so base64_encode_len(plainLen) fits
// within the base64_encode_len(MAX_LOGIN_SZ) stack buffer.
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Outdated
char base64buf[base64_encode_len(MAX_LOGIN_SZ)];
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struct base64_encode_ctx ctx;
base64_encode_init(&ctx);
char base64buf[base64_encode_len(MAX_LOGIN_SZ)];
size_t resultLen = base64_encode_update(&ctx, base64buf, request->extacl_user.size(), reinterpret_cast<const uint8_t*>(request->extacl_user.rawBuf()));
auto resultLen = base64_encode_update(&ctx, base64buf, userLen, reinterpret_cast<const uint8_t*>(request->extacl_user.rawBuf()));
resultLen += base64_encode_update(&ctx, base64buf+resultLen, 1, reinterpret_cast<const uint8_t*>(":"));
resultLen += base64_encode_update(&ctx, base64buf+resultLen, request->extacl_passwd.size(), reinterpret_cast<const uint8_t*>(request->extacl_passwd.rawBuf()));
resultLen += base64_encode_update(&ctx, base64buf+resultLen, passwdLen, reinterpret_cast<const uint8_t*>(request->extacl_passwd.rawBuf()));
resultLen += base64_encode_final(&ctx, base64buf+resultLen);
buf.appendf("Proxy-Authorization: Basic %.*s\r\n", (int)resultLen, base64buf);
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}
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22 changes: 17 additions & 5 deletions src/http.cc
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Expand Up @@ -1850,8 +1850,12 @@ httpFixupAuthentication(HttpRequest * request, const HttpHeader * hdr_in, HttpHe
username = request->auth_user_request->username();
#endif

blen = base64_encode_update(&ctx, loginbuf, strlen(username), reinterpret_cast<const uint8_t*>(username));
blen += base64_encode_update(&ctx, loginbuf+blen, strlen(request->peer_login +1), reinterpret_cast<const uint8_t*>(request->peer_login +1));
const auto usernameLen = strlen(username);
const auto suffixLen = strlen(request->peer_login + 1);
if (usernameLen + suffixLen > MAX_LOGIN_SZ)
throw TextException("peer login credentials too long", Here());
blen = base64_encode_update(&ctx, loginbuf, usernameLen, reinterpret_cast<const uint8_t*>(username));
blen += base64_encode_update(&ctx, loginbuf+blen, suffixLen, reinterpret_cast<const uint8_t*>(request->peer_login +1));
blen += base64_encode_final(&ctx, loginbuf+blen);
httpHeaderPutStrf(hdr_out, header, "Basic %.*s", (int)blen, loginbuf);
return;
Expand All @@ -1862,9 +1866,14 @@ httpFixupAuthentication(HttpRequest * request, const HttpHeader * hdr_in, HttpHe
(strcmp(request->peer_login, "PASS") == 0 ||
strcmp(request->peer_login, "PROXYPASS") == 0)) {

blen = base64_encode_update(&ctx, loginbuf, request->extacl_user.size(), reinterpret_cast<const uint8_t*>(request->extacl_user.rawBuf()));
const auto userLen = request->extacl_user.size();
const auto passwdLen = request->extacl_passwd.size();
// +1 for the ':' separator between user and passwd
if (userLen + 1 + passwdLen > MAX_LOGIN_SZ)
throw TextException("extacl credentials too long for peer login", Here());
blen = base64_encode_update(&ctx, loginbuf, userLen, reinterpret_cast<const uint8_t*>(request->extacl_user.rawBuf()));
blen += base64_encode_update(&ctx, loginbuf+blen, 1, reinterpret_cast<const uint8_t*>(":"));
blen += base64_encode_update(&ctx, loginbuf+blen, request->extacl_passwd.size(), reinterpret_cast<const uint8_t*>(request->extacl_passwd.rawBuf()));
blen += base64_encode_update(&ctx, loginbuf+blen, passwdLen, reinterpret_cast<const uint8_t*>(request->extacl_passwd.rawBuf()));
blen += base64_encode_final(&ctx, loginbuf+blen);
httpHeaderPutStrf(hdr_out, header, "Basic %.*s", (int)blen, loginbuf);
return;
Expand Down Expand Up @@ -1894,7 +1903,10 @@ httpFixupAuthentication(HttpRequest * request, const HttpHeader * hdr_in, HttpHe
}
#endif /* HAVE_KRB5 && HAVE_GSSAPI */

blen = base64_encode_update(&ctx, loginbuf, strlen(request->peer_login), reinterpret_cast<const uint8_t*>(request->peer_login));
const auto loginLen = strlen(request->peer_login);
if (loginLen > MAX_LOGIN_SZ)
throw TextException("peer_login too long", Here());
blen = base64_encode_update(&ctx, loginbuf, loginLen, reinterpret_cast<const uint8_t*>(request->peer_login));
blen += base64_encode_final(&ctx, loginbuf+blen);
httpHeaderPutStrf(hdr_out, header, "Basic %.*s", (int)blen, loginbuf);
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return;
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