105 lines
3.5 KiB
Diff
105 lines
3.5 KiB
Diff
From 73bb33a94ec67a53e7d805b12ad9264fa25f4f8d Mon Sep 17 00:00:00 2001
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From: Shawn O. Pearce <spearce@spearce.org>
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Date: Thu, 4 Jun 2009 18:33:32 -0700
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Subject: [PATCH] daemon: Strictly parse the "extra arg" part of the command
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Since 1.4.4.5 (49ba83fb67 "Add virtualization support to git-daemon")
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git daemon enters an infinite loop and never terminates if a client
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hides any extra arguments in the initial request line which is not
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exactly "\0host=blah\0".
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Since that change, a client must never insert additional extra
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arguments, or attempt to use any argument other than "host=", as
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any daemon will get stuck parsing the request line and will never
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complete the request.
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Since the client can't tell if the daemon is patched or not, it
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is not possible to know if additional extra args might actually be
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able to be safely requested.
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If we ever need to extend the git daemon protocol to support a new
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feature, we may have to do something like this to the exchange:
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# If both support git:// v2
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#
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C: 000cgit://v2
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S: 0010ok host user
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C: 0018host git.kernel.org
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C: 0027git-upload-pack /pub/linux-2.6.git
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S: ...git-upload-pack header...
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# If client supports git:// v2, server does not:
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#
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C: 000cgit://v2
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S: <EOF>
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C: 003bgit-upload-pack /pub/linux-2.6.git\0host=git.kernel.org\0
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S: ...git-upload-pack header...
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This requires the client to create two TCP connections to talk to
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an older git daemon, however all daemons since the introduction of
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daemon.c will safely reject the unknown "git://v2" command request,
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so the client can quite easily determine the server supports an
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older protocol.
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Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
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Signed-off-by: Junio C Hamano <gitster@pobox.com>
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diff --git a/connect.c b/connect.c
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index f6b8ba6..958c831 100644
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--- a/connect.c
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+++ b/connect.c
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@@ -579,7 +579,10 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
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git_tcp_connect(fd, host, flags);
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/*
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* Separate original protocol components prog and path
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- * from extended components with a NUL byte.
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+ * from extended host header with a NUL byte.
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+ *
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+ * Note: Do not add any other headers here! Doing so
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+ * will cause older git-daemon servers to crash.
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*/
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packet_write(fd[1],
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"%s %s%chost=%s%c",
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diff --git a/daemon.c b/daemon.c
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index daa4c8e..b2babcc 100644
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--- a/daemon.c
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+++ b/daemon.c
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@@ -406,15 +406,15 @@ static char *xstrdup_tolower(const char *str)
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}
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/*
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- * Separate the "extra args" information as supplied by the client connection.
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+ * Read the host as supplied by the client connection.
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*/
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-static void parse_extra_args(char *extra_args, int buflen)
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+static void parse_host_arg(char *extra_args, int buflen)
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{
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char *val;
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int vallen;
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char *end = extra_args + buflen;
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- while (extra_args < end && *extra_args) {
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+ if (extra_args < end && *extra_args) {
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saw_extended_args = 1;
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if (strncasecmp("host=", extra_args, 5) == 0) {
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val = extra_args + 5;
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@@ -436,6 +436,8 @@ static void parse_extra_args(char *extra_args, int buflen)
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/* On to the next one */
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extra_args = val + vallen;
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}
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+ if (extra_args < end && *extra_args)
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+ die("Invalid request");
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}
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/*
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@@ -545,7 +547,7 @@ static int execute(struct sockaddr *addr)
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hostname = canon_hostname = ip_address = tcp_port = NULL;
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if (len != pktlen)
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- parse_extra_args(line + len + 1, pktlen - len - 1);
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+ parse_host_arg(line + len + 1, pktlen - len - 1);
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for (i = 0; i < ARRAY_SIZE(daemon_service); i++) {
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struct daemon_service *s = &(daemon_service[i]);
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