--- Begin Message ---
- To: Debian Bug Tracking System <submit@bugs.debian.org>
- Subject: pu: package tremulous/1.1.0-8~squeeze1 (contrib)
- From: Simon McVittie <smcv@debian.org>
- Date: Thu, 29 Mar 2012 21:42:42 +0100
- Message-id: <20120329204242.GA4944@reptile.pseudorandom.co.uk>
Package: release.debian.org
Severity: normal
User: release.debian.org@packages.debian.org
Usertags: pu
This update reduces attackers' ability to perform a reflected DoS attack by
sending spoofed UDP packets to multiple Tremulous servers, by rate-limiting
large responses to those packets. It's the same thing as DSA-2442-1 in
OpenArena, but also incorporates a fix for a regression in that update
(I've just uploaded the corresponding fix for OpenArena to security-master).
As with -7~squeeze1, the security team have instructed me to go directly
to stable since Tremulous is contrib, and the source I propose to upload is
identical to what's in unstable (apart from the changelog).
The reporter of the corresponding OpenArena bug (#665665) is testing
pre-release versions of the Tremulous and OA updates on a public server
running squeeze, and hasn't reported any problems so far.
Changelog below; debdiff attached; separated patch also attached, for better
legibility.
Regards,
S
tremulous (1.1.0-8~squeeze1) stable; urgency=low
* Stable update, incorporating a security fix from unstable
-- Simon McVittie <smcv@debian.org> Thu, 29 Mar 2012 20:40:49 +0100
tremulous (1.1.0-8) unstable; urgency=medium
* Backport ioquake3 r1762, r1763, r1898 to rate-limit getstatus and
rcon connectionless packets, to avoid their use for traffic amplification.
CVE-2010-5077 (Closes: #665842)
* Fix an incorrect bug number in revision -6
-- Simon McVittie <smcv@debian.org> Tue, 27 Mar 2012 20:33:10 +0100
diffstat for tremulous-1.1.0 tremulous-1.1.0
changelog | 15
patches/0020-Rate-limit-getstatus-and-rcon-connectionless-request.patch | 263 ++++++++++
patches/series | 1
3 files changed, 279 insertions(+)
diff -Nru tremulous-1.1.0/debian/changelog tremulous-1.1.0/debian/changelog
--- tremulous-1.1.0/debian/changelog 2012-03-25 13:57:34.000000000 +0100
+++ tremulous-1.1.0/debian/changelog 2012-03-29 20:40:50.000000000 +0100
@@ -1,3 +1,18 @@
+tremulous (1.1.0-8~squeeze1) stable; urgency=low
+
+ * Stable update, incorporating a security fix from unstable
+
+ -- Simon McVittie <smcv@debian.org> Thu, 29 Mar 2012 20:40:49 +0100
+
+tremulous (1.1.0-8) unstable; urgency=medium
+
+ * Backport ioquake3 r1762, r1763, r1898 to rate-limit getstatus and
+ rcon connectionless packets, to avoid their use for traffic amplification.
+ CVE-2010-5077 (Closes: #665842)
+ * Fix an incorrect bug number in revision -6
+
+ -- Simon McVittie <smcv@debian.org> Tue, 27 Mar 2012 20:33:10 +0100
+
tremulous (1.1.0-7~squeeze1) stable; urgency=low
* Stable update (#663104), incorporating security fixes from unstable
diff -Nru tremulous-1.1.0/debian/patches/0020-Rate-limit-getstatus-and-rcon-connectionless-request.patch tremulous-1.1.0/debian/patches/0020-Rate-limit-getstatus-and-rcon-connectionless-request.patch
--- tremulous-1.1.0/debian/patches/0020-Rate-limit-getstatus-and-rcon-connectionless-request.patch 1970-01-01 01:00:00.000000000 +0100
+++ tremulous-1.1.0/debian/patches/0020-Rate-limit-getstatus-and-rcon-connectionless-request.patch 2012-03-27 22:05:46.000000000 +0100
@@ -0,0 +1,263 @@
+From: Simon McVittie <smcv@debian.org>
+Date: Sun, 3 Jan 2010 22:12:20 +0000
+Subject: Rate limit getstatus and rcon connectionless requests
+
+Backport of ioquake3 r1762, r1763, r1898, all by Tim Angus <tma>. This
+also incorporates a fix for a regression in r1762 in which the server would
+stop responding to getstatus after 2**32 ms (about 50 days).
+
+Changes to adapt to Tremulous:
+
+* Remove IPv6 support, Tremulous 1.1.0 does not do IPv6
+* Do not assume that NA_BAD == 0 (in this older version it's 1),
+ look for literal 0 as the indication that a hash bucket has only been
+ zero-filled and not properly initialized
+* Remove cosmetic (whitespace/comment) changes
+
+Origin: backport
+Bug-Debian: http://bugs.debian.org/665842
+CVE: CVE-2010-5077
+---
+ src/server/sv_main.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++---
+ 1 files changed, 200 insertions(+), 10 deletions(-)
+
+diff --git a/src/server/sv_main.c b/src/server/sv_main.c
+index f6d5a7c..9dfa6dc 100644
+--- a/src/server/sv_main.c
++++ b/src/server/sv_main.c
+@@ -332,6 +332,175 @@ CONNECTIONLESS COMMANDS
+ ==============================================================================
+ */
+
++typedef struct leakyBucket_s leakyBucket_t;
++struct leakyBucket_s {
++ netadrtype_t type;
++
++ union {
++ byte _4[4];
++ byte _6[16];
++ } ipv;
++
++ int lastTime;
++ signed char burst;
++
++ long hash;
++
++ leakyBucket_t *prev, *next;
++};
++
++// This is deliberately quite large to make it more of an effort to DoS
++#define MAX_BUCKETS 16384
++#define MAX_HASHES 1024
++
++static leakyBucket_t buckets[ MAX_BUCKETS ];
++static leakyBucket_t *bucketHashes[ MAX_HASHES ];
++
++/*
++================
++SVC_HashForAddress
++================
++*/
++static long SVC_HashForAddress( netadr_t address ) {
++ byte *ip = NULL;
++ size_t size = 0;
++ int i;
++ long hash = 0;
++
++ switch ( address.type ) {
++ case NA_IP: ip = address.ip; size = 4; break;
++ default: return 0;
++ }
++
++ for ( i = 0; i < size; i++ ) {
++ hash += (long)( ip[ i ] ) * ( i + 119 );
++ }
++
++ hash = ( hash ^ ( hash >> 10 ) ^ ( hash >> 20 ) );
++ hash &= ( MAX_HASHES - 1 );
++
++ return hash;
++}
++
++/*
++================
++SVC_BucketForAddress
++
++Find or allocate a bucket for an address
++================
++*/
++static leakyBucket_t *SVC_BucketForAddress( netadr_t address, int burst, int period ) {
++ leakyBucket_t *bucket = NULL;
++ int i;
++ long hash = SVC_HashForAddress( address );
++ int now = Sys_Milliseconds();
++
++ for ( bucket = bucketHashes[ hash ]; bucket; bucket = bucket->next ) {
++ switch ( bucket->type ) {
++ case NA_IP:
++ if ( memcmp( bucket->ipv._4, address.ip, 4 ) == 0 ) {
++ return bucket;
++ }
++ break;
++
++ default:
++ break;
++ }
++ }
++
++ for ( i = 0; i < MAX_BUCKETS; i++ ) {
++ int interval;
++
++ bucket = &buckets[ i ];
++ interval = now - bucket->lastTime;
++
++ // Reclaim expired buckets
++ if ( bucket->lastTime > 0 && ( interval > ( burst * period ) ||
++ interval < 0 ) ) {
++ if ( bucket->prev != NULL ) {
++ bucket->prev->next = bucket->next;
++ } else {
++ bucketHashes[ bucket->hash ] = bucket->next;
++ }
++
++ if ( bucket->next != NULL ) {
++ bucket->next->prev = bucket->prev;
++ }
++
++ Com_Memset( bucket, 0, sizeof( leakyBucket_t ) );
++ }
++
++ if ( bucket->type == 0 ) {
++ bucket->type = address.type;
++ switch ( address.type ) {
++ case NA_IP: Com_Memcpy( bucket->ipv._4, address.ip, 4 ); break;
++ default: break;
++ }
++
++ bucket->lastTime = now;
++ bucket->burst = 0;
++ bucket->hash = hash;
++
++ // Add to the head of the relevant hash chain
++ bucket->next = bucketHashes[ hash ];
++ if ( bucketHashes[ hash ] != NULL ) {
++ bucketHashes[ hash ]->prev = bucket;
++ }
++
++ bucket->prev = NULL;
++ bucketHashes[ hash ] = bucket;
++
++ return bucket;
++ }
++ }
++
++ // Couldn't allocate a bucket for this address
++ return NULL;
++}
++
++/*
++================
++SVC_RateLimit
++================
++*/
++static qboolean SVC_RateLimit( leakyBucket_t *bucket, int burst, int period ) {
++ if ( bucket != NULL ) {
++ int now = Sys_Milliseconds();
++ int interval = now - bucket->lastTime;
++ int expired = interval / period;
++ int expiredRemainder = interval % period;
++
++ if ( expired > bucket->burst ) {
++ bucket->burst = 0;
++ bucket->lastTime = now;
++ } else {
++ bucket->burst -= expired;
++ bucket->lastTime = now - expiredRemainder;
++ }
++
++ if ( bucket->burst < burst ) {
++ bucket->burst++;
++
++ return qfalse;
++ }
++ }
++
++ return qtrue;
++}
++
++/*
++================
++SVC_RateLimitAddress
++
++Rate limit for a particular address
++================
++*/
++static qboolean SVC_RateLimitAddress( netadr_t from, int burst, int period ) {
++ leakyBucket_t *bucket = SVC_BucketForAddress( from, burst, period );
++
++ return SVC_RateLimit( bucket, burst, period );
++}
++
+ /*
+ ================
+ SVC_Status
+@@ -350,6 +519,21 @@ void SVC_Status( netadr_t from ) {
+ int statusLength;
+ int playerLength;
+ char infostring[MAX_INFO_STRING];
++ static leakyBucket_t bucket;
++
++ // Prevent using getstatus as an amplifier
++ if ( SVC_RateLimitAddress( from, 10, 1000 ) ) {
++ Com_DPrintf( "SVC_Status: rate limit from %s exceeded, dropping request\n",
++ NET_AdrToString( from ) );
++ return;
++ }
++
++ // Allow getstatus to be DoSed relatively easily, but prevent
++ // excess outbound bandwidth usage when being flooded inbound
++ if ( SVC_RateLimit( &bucket, 10, 100 ) ) {
++ Com_DPrintf( "SVC_Status: rate limit exceeded, dropping request\n" );
++ return;
++ }
+
+ strcpy( infostring, Cvar_InfoString( CVAR_SERVERINFO ) );
+
+@@ -466,24 +650,30 @@ Redirect all printfs
+ */
+ void SVC_RemoteCommand( netadr_t from, msg_t *msg ) {
+ qboolean valid;
+- unsigned int time;
+ char remaining[1024];
+ // TTimo - scaled down to accumulate, but not overflow anything network wise, print wise etc.
+ // (OOB messages are the bottleneck here)
+ #define SV_OUTPUTBUF_LENGTH (1024 - 16)
+ char sv_outputbuf[SV_OUTPUTBUF_LENGTH];
+- static unsigned int lasttime = 0;
+ char *cmd_aux;
+
+- // TTimo - https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=534
+- time = Com_Milliseconds();
+- if (time<(lasttime+500)) {
++ // Prevent using rcon as an amplifier and make dictionary attacks impractical
++ if ( SVC_RateLimitAddress( from, 10, 1000 ) ) {
++ Com_DPrintf( "SVC_Status: rate limit from %s exceeded, dropping request\n",
++ NET_AdrToString( from ) );
+ return;
+ }
+- lasttime = time;
+
+ if ( !strlen( sv_rconPassword->string ) ||
+ strcmp (Cmd_Argv(1), sv_rconPassword->string) ) {
++ static leakyBucket_t bucket;
++
++ // Make DoS via rcon impractical
++ if ( SVC_RateLimit( &bucket, 10, 1000 ) ) {
++ Com_DPrintf( "SVC_Status: rate limit exceeded, dropping request\n" );
++ return;
++ }
++
+ valid = qfalse;
+ Com_Printf ("Bad rcon from %s:\n%s\n", NET_AdrToString (from), Cmd_Argv(2) );
+ } else {
+
diff -Nru tremulous-1.1.0/debian/patches/series tremulous-1.1.0/debian/patches/series
--- tremulous-1.1.0/debian/patches/series 2012-02-22 09:09:26.000000000 +0000
+++ tremulous-1.1.0/debian/patches/series 2012-03-27 22:05:46.000000000 +0100
@@ -17,3 +17,4 @@
0017-Sys_Error-do-not-overflow-if-an-error-message-exceed.patch
0018-Avoid-non-literal-format-strings.patch
0019-Annotate-printf-and-scanf-like-functions-with-gcc-at.patch
+0020-Rate-limit-getstatus-and-rcon-connectionless-request.patch
From: Simon McVittie <smcv@debian.org>
Date: Sun, 3 Jan 2010 22:12:20 +0000
Subject: Rate limit getstatus and rcon connectionless requests
Backport of ioquake3 r1762, r1763, r1898, all by Tim Angus <tma>. This
also incorporates a fix for a regression in r1762 in which the server would
stop responding to getstatus after 2**32 ms (about 50 days).
Changes to adapt to Tremulous:
* Remove IPv6 support, Tremulous 1.1.0 does not do IPv6
* Do not assume that NA_BAD == 0 (in this older version it's 1),
look for literal 0 as the indication that a hash bucket has only been
zero-filled and not properly initialized
* Remove cosmetic (whitespace/comment) changes
Origin: backport
Bug-Debian: http://bugs.debian.org/665842
CVE: CVE-2010-5077
---
src/server/sv_main.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 200 insertions(+), 10 deletions(-)
diff --git a/src/server/sv_main.c b/src/server/sv_main.c
index f6d5a7c..9dfa6dc 100644
--- a/src/server/sv_main.c
+++ b/src/server/sv_main.c
@@ -332,6 +332,175 @@ CONNECTIONLESS COMMANDS
==============================================================================
*/
+typedef struct leakyBucket_s leakyBucket_t;
+struct leakyBucket_s {
+ netadrtype_t type;
+
+ union {
+ byte _4[4];
+ byte _6[16];
+ } ipv;
+
+ int lastTime;
+ signed char burst;
+
+ long hash;
+
+ leakyBucket_t *prev, *next;
+};
+
+// This is deliberately quite large to make it more of an effort to DoS
+#define MAX_BUCKETS 16384
+#define MAX_HASHES 1024
+
+static leakyBucket_t buckets[ MAX_BUCKETS ];
+static leakyBucket_t *bucketHashes[ MAX_HASHES ];
+
+/*
+================
+SVC_HashForAddress
+================
+*/
+static long SVC_HashForAddress( netadr_t address ) {
+ byte *ip = NULL;
+ size_t size = 0;
+ int i;
+ long hash = 0;
+
+ switch ( address.type ) {
+ case NA_IP: ip = address.ip; size = 4; break;
+ default: return 0;
+ }
+
+ for ( i = 0; i < size; i++ ) {
+ hash += (long)( ip[ i ] ) * ( i + 119 );
+ }
+
+ hash = ( hash ^ ( hash >> 10 ) ^ ( hash >> 20 ) );
+ hash &= ( MAX_HASHES - 1 );
+
+ return hash;
+}
+
+/*
+================
+SVC_BucketForAddress
+
+Find or allocate a bucket for an address
+================
+*/
+static leakyBucket_t *SVC_BucketForAddress( netadr_t address, int burst, int period ) {
+ leakyBucket_t *bucket = NULL;
+ int i;
+ long hash = SVC_HashForAddress( address );
+ int now = Sys_Milliseconds();
+
+ for ( bucket = bucketHashes[ hash ]; bucket; bucket = bucket->next ) {
+ switch ( bucket->type ) {
+ case NA_IP:
+ if ( memcmp( bucket->ipv._4, address.ip, 4 ) == 0 ) {
+ return bucket;
+ }
+ break;
+
+ default:
+ break;
+ }
+ }
+
+ for ( i = 0; i < MAX_BUCKETS; i++ ) {
+ int interval;
+
+ bucket = &buckets[ i ];
+ interval = now - bucket->lastTime;
+
+ // Reclaim expired buckets
+ if ( bucket->lastTime > 0 && ( interval > ( burst * period ) ||
+ interval < 0 ) ) {
+ if ( bucket->prev != NULL ) {
+ bucket->prev->next = bucket->next;
+ } else {
+ bucketHashes[ bucket->hash ] = bucket->next;
+ }
+
+ if ( bucket->next != NULL ) {
+ bucket->next->prev = bucket->prev;
+ }
+
+ Com_Memset( bucket, 0, sizeof( leakyBucket_t ) );
+ }
+
+ if ( bucket->type == 0 ) {
+ bucket->type = address.type;
+ switch ( address.type ) {
+ case NA_IP: Com_Memcpy( bucket->ipv._4, address.ip, 4 ); break;
+ default: break;
+ }
+
+ bucket->lastTime = now;
+ bucket->burst = 0;
+ bucket->hash = hash;
+
+ // Add to the head of the relevant hash chain
+ bucket->next = bucketHashes[ hash ];
+ if ( bucketHashes[ hash ] != NULL ) {
+ bucketHashes[ hash ]->prev = bucket;
+ }
+
+ bucket->prev = NULL;
+ bucketHashes[ hash ] = bucket;
+
+ return bucket;
+ }
+ }
+
+ // Couldn't allocate a bucket for this address
+ return NULL;
+}
+
+/*
+================
+SVC_RateLimit
+================
+*/
+static qboolean SVC_RateLimit( leakyBucket_t *bucket, int burst, int period ) {
+ if ( bucket != NULL ) {
+ int now = Sys_Milliseconds();
+ int interval = now - bucket->lastTime;
+ int expired = interval / period;
+ int expiredRemainder = interval % period;
+
+ if ( expired > bucket->burst ) {
+ bucket->burst = 0;
+ bucket->lastTime = now;
+ } else {
+ bucket->burst -= expired;
+ bucket->lastTime = now - expiredRemainder;
+ }
+
+ if ( bucket->burst < burst ) {
+ bucket->burst++;
+
+ return qfalse;
+ }
+ }
+
+ return qtrue;
+}
+
+/*
+================
+SVC_RateLimitAddress
+
+Rate limit for a particular address
+================
+*/
+static qboolean SVC_RateLimitAddress( netadr_t from, int burst, int period ) {
+ leakyBucket_t *bucket = SVC_BucketForAddress( from, burst, period );
+
+ return SVC_RateLimit( bucket, burst, period );
+}
+
/*
================
SVC_Status
@@ -350,6 +519,21 @@ void SVC_Status( netadr_t from ) {
int statusLength;
int playerLength;
char infostring[MAX_INFO_STRING];
+ static leakyBucket_t bucket;
+
+ // Prevent using getstatus as an amplifier
+ if ( SVC_RateLimitAddress( from, 10, 1000 ) ) {
+ Com_DPrintf( "SVC_Status: rate limit from %s exceeded, dropping request\n",
+ NET_AdrToString( from ) );
+ return;
+ }
+
+ // Allow getstatus to be DoSed relatively easily, but prevent
+ // excess outbound bandwidth usage when being flooded inbound
+ if ( SVC_RateLimit( &bucket, 10, 100 ) ) {
+ Com_DPrintf( "SVC_Status: rate limit exceeded, dropping request\n" );
+ return;
+ }
strcpy( infostring, Cvar_InfoString( CVAR_SERVERINFO ) );
@@ -466,24 +650,30 @@ Redirect all printfs
*/
void SVC_RemoteCommand( netadr_t from, msg_t *msg ) {
qboolean valid;
- unsigned int time;
char remaining[1024];
// TTimo - scaled down to accumulate, but not overflow anything network wise, print wise etc.
// (OOB messages are the bottleneck here)
#define SV_OUTPUTBUF_LENGTH (1024 - 16)
char sv_outputbuf[SV_OUTPUTBUF_LENGTH];
- static unsigned int lasttime = 0;
char *cmd_aux;
- // TTimo - https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=534
- time = Com_Milliseconds();
- if (time<(lasttime+500)) {
+ // Prevent using rcon as an amplifier and make dictionary attacks impractical
+ if ( SVC_RateLimitAddress( from, 10, 1000 ) ) {
+ Com_DPrintf( "SVC_Status: rate limit from %s exceeded, dropping request\n",
+ NET_AdrToString( from ) );
return;
}
- lasttime = time;
if ( !strlen( sv_rconPassword->string ) ||
strcmp (Cmd_Argv(1), sv_rconPassword->string) ) {
+ static leakyBucket_t bucket;
+
+ // Make DoS via rcon impractical
+ if ( SVC_RateLimit( &bucket, 10, 1000 ) ) {
+ Com_DPrintf( "SVC_Status: rate limit exceeded, dropping request\n" );
+ return;
+ }
+
valid = qfalse;
Com_Printf ("Bad rcon from %s:\n%s\n", NET_AdrToString (from), Cmd_Argv(2) );
} else {
--- End Message ---