PemMemoryClientCertPresent now checks that the server saw the client's
certificate, as ClientCertPresent does. Before, it also passed when the
server built from PemMemory did not ask for a certificate at all.
The ClientCertPresent and ClientCertMissing helpers no longer pass
CLIENT_CA_CERT_DIR, which is "." and makes Mbed TLS parse every file in
the test directory, test binaries included, on each server they build.
The CA file is all they need. That makes TrustDirOptional, which built
the same server and client, a duplicate, so it goes. The tests that
still pass the directory keep the constructor taking one covered.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
Make ClientCertStillRequired take the setup to apply, so the
update_certs_pem test runs the same pair as the verify callback tests:
a client without a certificate is rejected and one with a certificate
is still accepted. Rejection alone would also pass if the update broke
the server for every client.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
Split the rejection scenario out of ClientCertMissing so it can run
against any server, then use it to check that a server built from
PemMemory with a client CA, and a server whose certificates were
replaced with update_certs_pem, both reject a client without a
certificate.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
On BoringSSL, SSL_get1_session() after a TLS 1.3 handshake gives a
session that cannot be resumed; the tickets come only through the
new-session callback, which its documentation recommends. Store the
session from that callback, so the resumption tests resume there too.
ThrowingVerifyCallbackRejectsTheCertificate and
ErrorAndExceptionHandlersReplaceProvider throw from a callback, which
does not compile with CPPHTTPLIB_NO_EXCEPTIONS and -fno-exceptions.
windows.h defines max() as a macro, which broke the Windows builds at
the two time_point::max() calls the handshake deadline added. Wrap them
in parentheses, as the other max() calls are.
Both sides of the merge tested the same behavior. Keep one test of
each: ClientCertStillRequired* for a server keeping client certificates
required, which covers a cleared callback too, VerifierStaysWithItsClient
for per-client verifiers across threads, and the Keep* redirect tests,
which share one helper. KeepSessionVerifier now also checks the error,
as the dropped SessionVerifier did.
Both sides keep TLS verify callbacks per context. Keep this side's
storage, which lets a handshake keep the callback it is running and
takes an exception from it as a rejection, and take the other side's
apply_verify_mode(), which works out the verify mode in one place on
every backend, with Mbed TLS and wolfSSL client contexts verifying by
default. Mbed TLS installs its verify callback on every session, and
each session runs its own copy of the user's callback. The redirect
client setup that both sides added is kept once.
name and filename are read as RFC 9110 quoted-strings, while browsers
send a backslash as it is, so from a browser a value with "\\" in it
arrives with a single backslash, and one ending in "\" is misread.
Through a plain-HTTP proxy the request line carries the absolute form,
while the Digest uri stays in origin form, as curl sends it. The comment
cited RFC 7616 3.4, which asks for the effective request URI.
A resumed handshake does not show the client certificate again, so since
OpenSSL mTLS servers resume sessions, a verify callback, such as one
checking a deny list, was skipped for as long as the ticket was good
(7200 s by default). Turn off session tickets, TLS 1.3 ones included,
and the session cache on a context with a callback, as on wolfSSL.
A server sending "102 Processing" without end kept the client reading
them unless max_timeout was set. Skip at most
CPPHTTPLIB_INTERIM_RESPONSE_MAX_COUNT (100) and fail with Error::Read
past it.
Client took any string with "//" in it that it could not use as a URL
for a bad URL, so a Unix socket path such as /run/app//api.sock gave an
invalid client. Only a string that starts with a scheme and "://", or
with "//", is taken for a URL now.
set_content_provider() and file content added their Content-Type next to
the one an earlier set_content() had set, so the response went out with
two, and clients took the first. Each content setter now replaces it. A
Content-Type set after set_file_content() is used for the file.
A content provider without a length or chunked coding sends a body that
only the end of the connection delimits (RFC 9112 6.3), yet the response
offered keep-alive, so a keep-alive client waited for the server's idle
timeout. Send Connection: close and close after it, as Go's net/http
does. A Content-Length set by the handler is still dropped; the
overload that takes a length frames such a body.
An exception from a verify callback unwound through the TLS library,
which is C: OpenSSL leaked the objects of the handshake, and a server
worker thread ended the process. It also left the handshake count that
update_certs_pem() waits on raised, so with a task queue that caught the
exception, every later update waited forever. Take the exception as a
rejection, and lower the count on every way out of the handshake.
Replacing a verify callback, as set_server_certificate_verifier() does,
deleted the one that a handshake on another thread could be running, on
OpenSSL and wolfSSL. Handshakes now share the callback and take their
reference under a lock, and SSLClient replaces it under the lock that
guards creating a session from its context.
tls::set_verify_callback() set the verify mode anew, so on a server that
required client certificates it made them optional: OpenSSL and wolfSSL
dropped SSL_VERIFY_FAIL_IF_NO_PEER_CERT, and Mbed TLS went from REQUIRED
to OPTIONAL. A client without a certificate got through. Keep what the
server requires.
update_server_client_ca() rotated the session ticket keys with 80 bytes,
which only OpenSSL takes. BoringSSL and LibreSSL take 48, refused them,
and the result was not checked, so a client went on resuming with a
ticket from before the client CA changed. Use the size each library
takes, and fail the update when the keys cannot be set.
Reset last_ssl_error_ and last_backend_error_ at the start of each
attempt in send_() rather than once in send(), so a request that
succeeds on the SSLPeerCouldBeClosed_ retry does not report the TLS
error of the attempt before it.
Now that every request writes those members, hold request_mutex_ until
the Result has read them, so another thread's request on the same
client cannot reset or replace them in between.
Also pick the TLS error up in a lambda in SSLClient::process_socket()
instead of through an out-parameter on process_client_socket_ssl(),
which has no other caller.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
A request that fails after the TLS handshake reports Error::Read or
Error::Write, and SSLSocketStream dropped the TLS error behind it. On
TLS 1.3, where a server rejects a client without a certificate only
after the handshake, ssl_error() and ssl_backend_error() were 0 instead
of showing, for example, OpenSSL's "tlsv13 alert certificate required".
SSLSocketStream now keeps the error from its last failed TLS read or
write, and SSLClient copies it into the values Result reports. Error
itself stays Read or Write.
Those values are also reset at the start of each request, so a later
successful request no longer reports the TLS error of an earlier one. A
client whose TLS context failed to set up keeps reporting that error.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
wolfSSL shares its session cache between contexts, so a session resumed
on a server that checks client certificates could carry a certificate
checked against another server's CA, or against a client CA replaced
since. Such a server no longer resumes sessions.
Without a session id context, OpenSSL answers a client resuming its
session with a fatal alert once client certificates are verified, which
curl and browsers run into on their second connection. Set one on every
server context. A changed client CA still stops resumption, as fcf7568
flushes the cache and rotates the ticket keys.
With set_ca_cert_store() after load_ca_cert_store(), the redirect client
trusted the earlier PEM too, though the store had replaced it, and of
several load_ca_cert_store() calls it kept only the last. Take the CAs
from the context when a store was set, and from every PEM loaded
otherwise.
Hostname verification on these backends fell back to the subject CN
even when the certificate had a DNS SAN, unlike X509_check_host and
RFC 6125 6.4.4. It does so only without one now. Mbed TLS also reads
the CN by its OID instead of searching the formatted DN for "CN=", and
no longer stops at an empty SAN.
The Digest uri and A2 took the raw path, while the request line carried
it encoded, with the params and without the fragment, so a server
comparing the two rejected the credentials. Build the target in one
place for both.
set_keep_alive_max_count(0) tripped an assert, a negative WebSocket ping
interval sent pings in a tight loop, and the form length, multipart file
count and range count macros rejected every request at 0. Make 0 mean
no limit for those, and a ping interval of 0 or less turn pings off. The
URI, header and line bounds cannot be lifted, so a static_assert keeps
them positive.
An event stream has no end, but the client's payload_max_length, 100MB
by default, cut it and made the client reconnect. SSEClient lifts that
limit for its stream; each event stays bounded by
CPPHTTPLIB_SSE_MAX_EVENT_LENGTH.
Files have been read with pread() since 44658e6, so the mapping went
unused. Keep only the descriptor, open it close-on-exec and without
waiting on a FIFO, and accept only a regular file, so that a device is
no longer served as an empty body.
A quoted boundary kept its quoted-pairs, as only the quotes were taken
off, and the multipart writer sent a backslash as it was, so a name
ending in one escaped the closing quote for this library's own parser.
Unescape \" and \\ in media type parameters as in Content-Disposition,
and write a backslash as \\.
append_query_params() added the parameters after a '#', where the
fragment, which is not sent, took them along, and write_request() read a
query that came after one. Insert them before the fragment, and leave
the fragment out of the query.
A response framed by Transfer-Encoding next to a Content-Length, or an
HTTP/1.0 response with Transfer-Encoding, left the connection open for
the next request, though RFC 9112 6.1 has such framing treated as faulty
and the connection closed after it. Close it, with the check the server
makes for requests now shared.
On TLS 1.3 the server rejects a client without a certificate only after
the client has finished its side of the handshake, so the client notices
either when it writes the request or when it reads the response. CI saw
the write fail on Windows (OpenSSL) and once on macOS (Mbed TLS), which
ClientCertMissing did not accept.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
get_ca_certs() handed out heap copies of the context's CA certificates,
but free_cert() frees nothing on Mbed TLS, so every copy leaked. Hand
out the context's own certificates instead, as get_peer_certs() does
the session's, and say on the declaration that they last only as long
as the context's CA certificates stay as they are.
This showed up on every redirect from a client given a store with
set_ca_cert_store(), which passes the store on through these
certificates.
The ClientCertStillRequired tests call tls::set_verify_callback(), whose
declaration lives below the split border, so test_split failed to compile.
Declare it next to create_ca_store(), which the split build needs for the
same reason.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
A content provider that wrote past the length it was given put the
extra bytes after the framed body, where a keep-alive peer read them as
the next message. Write only what fits and fail the write, on both the
server and the client.
Content-Length and Transfer-Encoding a handler set were sent next to
the ones the library worked out, for ranges and compression, and a
post-routing handler could change the body after Content-Length was
set. Work both out in one place, from the body about to be written,
again after the post-routing handler; a HEAD response keeps the length
its handler gave it. A 1xx, 204 or 304 response sends no body and,
following RFC 9110 8.6, no Content-Length.
The client still sends a Content-Length or Transfer-Encoding its caller
passes, as curl and urllib3 do, and the README says these have to match
the body.
The read timeout applied to each read of the request line and headers,
so a client that sent them a byte now and then held a worker for as
long as it liked, and enough such clients left no worker for anyone
else. Bound the whole head by the read timeout, as the TLS handshake
already is, through a new Stream::set_max_timeout() that the socket
streams implement with their existing max timeout.
A request body is still bounded per read, and a WebSocket holds its
worker for its whole life. The README says so, and points to a
reverse proxy and the pre-request handler for untrusted clients.
Use ASSERT_FALSE and FAIL() instead of their hand-written forms, drop an
unused using-directive and a comment that restated the code, and fix the
section comment that still referred to get_peer_cert().
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
ClientCertPresent() and ClientCertMissing() now take a setup step for the
server, bind to any port instead of the legacy PORT, and the two new tests
are just calls to them.
ClientCertMissing also no longer checks the server certificate: with it
checked, the request failed because cert.pem is not trusted, whether or not
the server asked for a client certificate, so the test never exercised the
client certificate requirement. A rejected client is reported as
SSLConnection, or as Read on TLS 1.3, where the client only notices on its
first read.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
set_verify_client() and set_verify_callback() each set the verify mode on
their own, and set_verify_callback() ignored whether the peer's certificate
was required. A server that required client certificates therefore stopped
requiring them as soon as a verify callback was set on its context (OpenSSL,
Mbed TLS, wolfSSL) or set and then cleared again (OpenSSL, Mbed TLS).
Compute the mode from "peer certificate required" and "callback set" in one
helper per backend and call it from set_verify_client(),
set_verify_callback() and the context constructors. The context now records
that a client verifies the server by default, so clearing a callback on a
client context restores that default.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
A retry or redirect after an early answer to Expect: 100-continue now
opens a new connection, interim responses are also skipped while
waiting for 100 Continue, and a URL Client cannot use, such as one with
userinfo, gives an invalid client. Only a 407 is passed on from a
refused CONNECT, WebSocket::close() sends only a valid payload, and the
SSE client stops on an oversized event rather than reconnect to it.
Media type parameter names and user extension mappings are matched
without case, file content is read in larger chunks from a buffer of
its own, the streaming decompression limit reports
ExceedMaxPayloadSize, and the tests use the existing single-response
server helpers. Comments and the README are brought in line.
The server fuzzer's stream exposed no buffered data, so the fast path of
stream_line_reader::getline was never fuzzed. Hand out what a read
pulled in beyond the bytes asked for, as SocketStream does.
Over TLS a file is copied out of its mapping in this process, so one
truncated while it was being served raised SIGBUS and took the whole
server down. Read it with pread, which comes up short instead.
Credentials and the client certificate stay behind; other headers,
default ones included, go along as RFC 9110 15.4 has it, and so do the
limits and the TLS settings.
A wss client could set its CAs but had no way to pin a certificate. Add
set_server_certificate_verifier() and set_session_verifier(), as
SSLClient has.
INDEX.HTML got the default type, a REMOTE_ADDR spelled in lower case got
past the guard on prohibited header names, and Multipart/Form-Data was
not taken for multipart, though RFC 9110 makes field names and media
types case-insensitive and web servers match extensions so.
OpenSSL allowed client-initiated renegotiation, which runs a handshake
update_certs_pem() does not wait for, and kept sessions and ticket keys
across a change of client CAs, so a client verified under the old ones
could resume. wolfSSL added new client CAs to the old instead of
replacing them, and a bad certificate or key left Mbed TLS and wolfSSL
half updated.
Turn renegotiation off, forget the sessions and ticket keys on a client
CA change, replace wolfSSL's CAs, and check new material before swapping
it in. Note that the update must not be called from a TLS callback.
The Mbed TLS and wolfSSL backends matched *.com, a bare *, vic*.test and
names with empty labels, which OpenSSL rejects. Require two labels after
a wildcard, none in an IDNA label and no empty label, and ignore a
trailing dot on the host, so every backend accepts the same names.
On Mbed TLS and wolfSSL the verification mode is a setting of the
context, and it was changed outside the lock that guards creating a
session from that context.
Any Close payload was echoed back, a 1-byte one, a code that may not be
sent and a reason that is not UTF-8 included. Echo a valid one and
answer the others with 1002, from one place for both read loops.
A non-200 answer to CONNECT was returned as the response, so a proxy, or
anyone on the plain leg to it, could answer an HTTPS request as if the
origin had. Fail the request with Error::ProxyConnection for anything
but a 4xx or 5xx refusal.
Only 100 Continue was skipped, and only without header fields, so a 103
Early Hints was taken for the final response and a 100 with fields threw
the parsing off. Skip every 1xx but 101, along with its header fields.
When the final response came before 100 Continue, the body was never
sent but the connection was kept, so the server could read the next
request as that body. Close it after the response.
parse_url took http://user@evil.com/ for the host "user@evil.com", where
parsers that honour userinfo, or read a backslash as '/', see evil.com.
userinfo is not supported, so reject both.
When the real path of a file under a mount point could not be resolved,
the check that it stays inside the mount point was skipped and the file
was served. Do not serve it from there, and refuse a mount point whose
directory cannot be resolved.
decode_path_component dropped a %u escape of a surrogate, joining what
was on either side of it, so /ad%uD800min became /admin after a filter
had seen something else. Keep such an escape as it is.
Any run of spaces or tabs separated the parts of the request line, a
fragment in the target was stripped, and an HTTP/1.1 request without
Host was served, so a server or a cache in front that follows RFC 9112
could see another request. Require a single SP between the parts, and
answer a target with '#' and an HTTP/1.1 request without Host with 400.
The client no longer sends the fragment of a URL.
RFC 9112 6.1 has a server close the connection after answering a
request with both Transfer-Encoding and Content-Length, or with
Transfer-Encoding in HTTP/1.0. Close it, and send Connection: close
whenever the connection closes after a response.
split_unquoted ended a quoted-string at an escaped quote, so
name="a\"; filename=evil.php" came apart into a name and a filename that
a parser in front following RFC 9110 would not see. Skip quoted-pairs
when splitting, and unescape \" and \\ in Content-Disposition values,
leaving other backslashes, such as those of a Windows path, as they are.
A part header arriving a few bytes at a time was searched for its CRLF
from the start on every read, which made parsing it quadratic. Remember
how far the search got.
The SSE client buffered a line, or the data of an event, with no limit
of its own, and with payload_max_length(0) with none at all. Add
CPPHTTPLIB_SSE_MAX_EVENT_LENGTH (16MB) and end the connection with
ExceedMaxPayloadSize past it.
Every continuation frame could be as long as the whole message limit,
and the total was checked only after appending it, so a fragmented
message could take about twice the limit. Read each fragment against
what is left, with room for a control frame between them.
The client reserved what Content-Length claimed, up to
payload_max_length, before any of the body arrived, and without a limit
nothing bounded it. Reserve at most 1 MiB up front and let a longer body
grow as it is read.
An unsupported scheme without exceptions, or a port out of range, left
Client with no implementation, so the first request after it went
through a null pointer. Put a client in its place that reports itself
invalid and fails every request with Error::Connection.
CPPHTTPLIB_WEBSOCKET_MAX_PAYLOAD_LENGTH = 0 rejected every frame with a
payload, while 0 means no limit for payload_max_length. Make it mean the
same here, and refuse a length that size_t cannot hold.
set_payload_max_length(0) means no limit, but StreamHandle compared the
decompressed size against 0, so every compressed response read through
the streaming API failed.
case_ignore::hash recursed once per character of the key, and trailer
field names from the wire reach it, so a long one could overflow the
stack of a build that keeps the recursion (-O0). Hash in a loop instead,
which gives the same values.
Remove the now-unused forward declaration and the null checks that can no
longer fire, since create_session() always sets the session and its
context before installing the callback, and shorten the comments.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
find_content_type(), can_compress_content_type() and
is_prohibited_header_name() switched on a 26-bit hash of the name and
never compared the name itself, so any name that hashed alike was taken
for a known one. An uploaded file with an unknown extension could be
served as text/html, for one.
Compare the names themselves, and drop the hash and its literal
operator, which nothing else uses.
Every session now gets mbedtls_verify_callback(), which reads the user's
callback from the owning context when the handshake runs. The
has_verify_callback flag and the separate hostname-masking callback are no
longer needed, and a callback set after a session was created is still
honoured.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
* Carry the server certificate verifier over to the redirect client
create_redirect_client() now copies the CA store and the session verifier
to the SSLClient it builds for a cross-host https redirect (#2632), but a
verifier given to set_server_certificate_verifier() was still dropped: the
redirect client's ctx never had the verify callback wired in, so a
pinning verifier never ran on the host the server redirects to.
SSLClient now keeps its own copy of the verifier, since ctx_ cannot report
it back and the backends hold it in a slot shared by every client, and
installs it on the redirect client. The copy also replaces the
Windows-only server_certificate_verifier_set_ flag.
SSLClientRedirectTest.ServerCertificateVerifier fails before this change
and passes after (OpenSSL 3, Mbed TLS 2.28, wolfSSL 5.6).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
* Clarify the server_certificate_verifier_ comment
The backends keep the verify callback in a per-thread slot, not one
shared by every client.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WGAYpQgXt95LdDQcJYgjB8
---------
Co-authored-by: Claude <noreply@anthropic.com>
tls::set_verify_callback() kept the callback in a thread_local slot, so two
SSLClients configured on one thread overwrote each other's verifier, and a
client used from another thread ran none. Keep it with the context instead
(OpenSSL SSL_CTX ex_data, MbedTlsContext/WolfSSLContext member) and have each
backend trampoline look it up from the session's context.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013wxevjmRqzpy8qDAD3vdwr
update_certs_pem() replaced the certificate, key and client CAs inside
the TLS context while handshakes on other threads were still reading
them, and only the creation of a session was serialized with it. A
server rotating its certificates under load could crash.
Count the handshakes in progress, make an update wait until there are
none, and hold off new handshakes while an update is pending so that a
steady stream of them cannot keep it waiting. The wait is bounded by
the handshake timeout.
The handshake loops gave every wait for the socket the full timeout
again, so a peer that sent a byte now and then kept a handshake going,
and the worker serving it, for as long as it liked. Work out the
deadline once and wait only for what is left of it, on both sides and in
every backend.
A cross-host redirect is followed by a new client, which did not get the
payload limit, the max timeout, the connection timeout's microseconds or
the hostname address map. Over HTTPS it also lost the session verifier,
the server certificate verifier and a store given to set_ca_cert_store(),
and fell back to the default CAs. Copy them over. The store belongs to
the original TLS context, so pass on the CA certificates it holds as PEM.
After the redirect, the original client also answered a 401 or 407 from
the new host with its own digest credentials and sent that to its own
host, with the new host's path. Return the redirected response as it is,
since the client that followed it has already answered what it could.
read_websocket_frame() resized the payload to the length a frame header
declared before reading any of it, so a 14-byte header made the peer
allocate and zero-fill up to CPPHTTPLIB_WEBSOCKET_MAX_PAYLOAD_LENGTH and
hold it until the read timed out. 70 such headers took a server to over
1 GB, and a client reading from a hostile server was exposed the same way.
Read the payload in CPPHTTPLIB_RECV_BUFSIZ chunks and grow it by each one,
so memory follows the bytes that actually came in.
std::regex_match recursed once per character of a status line's reason
phrase, so a server that sent one as long as a whole line overflowed the
client's stack. file_extension() and append_query_params() ran the same
kind of regex over a request path and a caller's path.
Parse all three by hand, with the same results, except that a path that
starts with '?' now gets its parameters joined with '&'. Serving a static
file no longer defers the content type lookup to keep a regex off the 304
path, so it looks the type up once.
FileContentProviderStaysWithinFile, added in e374966, calls
detail::set_file_content_provider, which split.py moves into httplib.cc,
so test_split did not compile. Declare it in the test, as the other tests
that call into detail:: already do.
When a content receiver returned false, or threw, partway through a body,
the drain after the response read a whole Content-Length again from where
it stopped. It swallowed the start of the next request, so the rest was
parsed as a request of its own once the handler answered below 400. A
handler that called the content reader a second time read into the next
request the same way.
Mark the body once reading starts, and if it does not finish, answer with
Connection: close and never drain it from the middle. Let each request's
body be read only once.
The wolfSSL verify callback set VerifyContext::session to the raw WOLFSSL
pointer, while every other tls:: function takes the WolfSSLSession that
wraps it, so passing ctx.session on from a verifier read the wrong type.
Point each WOLFSSL back to its WolfSSLSession and hand that out instead,
as the OpenSSL and Mbed TLS backends already do with their own handles.
tls::set_verify_callback(), which set_server_certificate_verifier() uses,
stored the callback in a single thread_local slot shared by every context.
A verifier was skipped when the handshake ran on another thread, ran for
other clients on the thread that set it, and could run after its client
was destroyed.
Store it with the context instead: in SSL_CTX ex_data for OpenSSL, and in
MbedTlsContext and WolfSSLContext for Mbed TLS and wolfSSL.
set_content() did not drop a content provider installed earlier, and
apply_ranges() then took the body's size as the Content-Length while the
provider was still the one written. The provider was asked for more bytes
than it had: a file under a mount point went out under the error status a
file request handler set to hide it, its mapping was read past the end,
and a user provider read past its own data.
Make every content setter clear the other sources so the last one wins,
let a body assigned directly after a provider or a file win as well, and
never read past the mapping in the file content provider.
2026-10-16 03:58:42 -04:00
10 changed files with 4103 additions and 1149 deletions
An event, or a line still waiting for its end, longer than `CPPHTTPLIB_SSE_MAX_EVENT_LENGTH` (16MB by default, `0` for no limit) ends the connection with `Error::ExceedMaxPayloadSize`, and the client stops rather than reconnect to the same event. The client's `set_payload_max_length()` does not apply to the stream as a whole, which has no end.
The server accepts a handshake from any `Origin`. A browser sends its cookies with a handshake another site starts, so if cookies authenticate the connection, also check `req.get_header_value("Origin")` against your own origins in one of these handlers (cross-site WebSocket hijacking).
| `CPPHTTPLIB_WEBSOCKET_SERVER_READ_TIMEOUT_SECOND` | `300` | Server read timeout (seconds) |
| `CPPHTTPLIB_WEBSOCKET_CLOSE_TIMEOUT_SECOND` | `5` | Timeout for waiting peer's Close response (seconds) |
@@ -478,7 +484,7 @@ With the default ping interval of 30 seconds, `max_missed_pongs = 2` detects a d
## Threading Model
WebSocket connections share the same thread pool as HTTP requests. Each WebSocket connection occupies one thread for its entire lifetime.
WebSocket connections share the same thread pool as HTTP requests. Each WebSocket connection occupies one thread for its entire lifetime, so a client opening many of them can leave none for HTTP requests. Reject the upgrades you do not want in `set_pre_request_handler()`, before the connection takes a thread for good.
The default thread pool uses dynamic scaling: it maintains a base thread count of `CPPHTTPLIB_THREAD_POOL_COUNT` (8 or `std::thread::hardware_concurrency() - 1`, whichever is greater) and can scale up to 4x that count under load (`CPPHTTPLIB_THREAD_POOL_MAX_COUNT`). When all base threads are busy, temporary threads are spawned automatically up to the maximum. These dynamic threads exit after an idle timeout (`CPPHTTPLIB_THREAD_POOL_IDLE_TIMEOUT`, default 3 seconds).
@@ -72,6 +72,8 @@ cpp-httplib supports multiple TLS backends through an abstraction layer:
> [!NOTE]
> **wolfSSL limitation:** `get_ca_certs()` and `get_ca_names()` only reflect CA certificates loaded via `load_ca_cert_store()`. Certificates loaded through `set_ca_cert_path()` or system certificates (`load_system_certs`) are not enumerable.
>
> A wolfSSL server that verifies client certificates does not resume TLS sessions: wolfSSL shares its session cache between contexts, so a resumed session could carry a certificate checked against another server's client CA.
> [!NOTE]
> **BoringSSL (best-effort):** BoringSSL builds under `CPPHTTPLIB_OPENSSL_SUPPORT` and is exercised by CI against current upstream. Because BoringSSL does not guarantee API stability, support is best-effort — breakage may occasionally land. Two known behavioral differences vs OpenSSL: (1) BoringSSL's public headers require C++14 or later, so consumers must compile accordingly; (2) hostname verification is SAN-only per RFC 6125 §6.4.4 (no CN fallback).
> The CA certificates are loaded when the client makes its first connection. Changing `set_ca_cert_path()` or `enable_system_ca()` after that has no effect, so make the settings before the first request, or use a new client. `set_ca_cert_store()` and `load_ca_cert_store()` take effect at once. `WebSocketClient` works the same way.
### SSL Error Handling
When SSL operations fail, cpp-httplib provides detailed error information through `ssl_error()` and `ssl_backend_error()`:
* `Allow` and the WebDAV `DAV:` header are not generated automatically. Register an `Options` handler if clients need them.
The request line itself is read strictly, as RFC 9112 asks: a single space between its three parts, no fragment (`#...`) in the target, and a `Host` header in every HTTP/1.1 request. Anything else gets `400 Bad Request`.
### Bind a socket to multiple interfaces and any available port
It is not called for `HEAD` requests or `304 Not Modified` responses, so do not use it for access control; use `set_pre_routing_handler()`.
### Logging
cpp-httplib provides separate logging capabilities for access logs and error logs, similar to web servers like Nginx and Apache.
@@ -717,6 +726,9 @@ auto safe = httplib::sanitize_filename(file.filename);
This function strips path separators (`/`, `\`), null bytes, leading/trailing whitespace, and rejects `.` and `..`. Returns an empty string if the filename is unsafe.
> [!NOTE]
> `name` and `filename` are read as quoted-strings (RFC 9110 §5.6.4), where `\"` and `\\` stand for `"` and `\`. Browsers send a backslash as it is, so from a browser, a value with `\\` in it arrives with a single `\`, and one that ends in `\` is not read correctly.
> When the request body content type is 'www-form-urlencoded', the actual payload length shouldn't exceed `CPPHTTPLIB_FORM_URL_ENCODED_PAYLOAD_MAX_LENGTH`.
> When the request body content type is 'www-form-urlencoded', the actual payload length shouldn't exceed `CPPHTTPLIB_FORM_URL_ENCODED_PAYLOAD_MAX_LENGTH` (`0` for no limit).
### Server-Sent Events
@@ -910,6 +927,8 @@ Please see [Server example](https://github.com/yhirose/cpp-httplib/blob/master/e
When all threads are busy and a new task arrives, a temporary thread is spawned (up to the maximum). A dynamic thread exits automatically once it has waited for the idle timeout without receiving a task. The idle timeout defaults to 3 seconds, configurable via `CPPHTTPLIB_THREAD_POOL_IDLE_TIMEOUT`.
A connection holds its thread while it is served: between requests up to the keep-alive timeout, through a request body sent slowly but within the read timeout, and for the whole life of a WebSocket. Enough of them leave no thread for anyone else, so in front of untrusted clients, put a reverse proxy that limits connections per client, and reject unwanted WebSocket upgrades in the pre-request handler.
If you want to set the thread counts at runtime:
```cpp
@@ -1116,6 +1135,8 @@ cli.set_default_headers({
auto res = cli.Get("/hi");
```
A `Content-Length` or `Transfer-Encoding` among these headers is sent in place of the one the library would send, so it has to describe the body as written. Leave both out when passing on the headers of another message, as a proxy does.
> A TLS backend (OpenSSL, Mbed TLS, or wolfSSL) is required for Digest Authentication.
When the proxy refuses the `CONNECT` of an HTTPS request, the request fails with `Error::ProxyConnection`. Only a `407 Proxy Authentication Required` comes back as the response, since any other answer from the proxy could be taken for the origin's.
#### Bypass the proxy for specific hosts (`NO_PROXY`)
```cpp
@@ -1388,6 +1411,10 @@ res = cli.Get("/");
res->status; // 200
```
A URL with userinfo (`http://user:pass@host/`) is not supported, neither for a `Client` nor in a `Location`; use `set_basic_auth()` for the credentials.
On a redirect to another host, `Authorization`, `Cookie` and `Proxy-Authorization` are dropped along with the credentials set with `set_basic_auth()`, `set_bearer_token_auth()` and `set_digest_auth()`, and the client certificate is not presented. Other headers, the default ones included, go along (RFC 9110 §15.4), and so do the timeouts, the payload limit and the TLS verification settings.
> svr.Get(R"(/api/v\d+/.*)", handler); // Regex route, limited to short paths
> ```
>
> The limit is no guarantee on a thread with a small stack, such as one of musl's 128KB threads, where a pattern like `(\w|-)+` can already overflow on a shorter path; lower the limit there. Nor does it bound the time a pattern with nested repetition, such as `((\w+-?)+)`, can take to fail on a few dozen characters. Keep regex routes simple.
@@ -60,7 +60,7 @@ Before a certificate expires, you may want to swap it out without restarting the
svr.update_certs_pem(new_cert_pem,new_key_pem);
```
Existing connections keep using the old cert; new connections use the new one.
Existing connections keep using the old cert; new connections use the new one. It waits for handshakes in progress to finish, at most the read timeout, and new connections wait until it returns. So don't call it from a TLS callback that runs during a handshake: it would wait for that handshake.
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