KNOWNBUGS revision 80785
138032Speter 238032Speter 338032Speter K N O W N B U G S I N S E N D M A I L 438032Speter 538032Speter 638032SpeterThe following are bugs or deficiencies in sendmail that I am aware of 738032Speterbut which have not been fixed in the current release. You probably 864562Sgshapirowant to get the most up to date version of this from ftp.sendmail.org 938032Speterin /pub/sendmail/KNOWNBUGS. For descriptions of bugs that have been 1038032Speterfixed, see the file RELEASE_NOTES (in the root directory of the sendmail 1138032Speterdistribution). 1238032Speter 1338032SpeterThis list is not guaranteed to be complete. 1438032Speter 1566494Sgshapiro* Delivery to programs that generate too much output may cause problems 1666494Sgshapiro (8.10, 8.11) 1738032Speter 1866494Sgshapiro If e-mail is delivered to a program which generates too much 1966494Sgshapiro output, then sendmail may issue an error: 2066494Sgshapiro 2166494Sgshapiro timeout waiting for input from local during Draining Input 2266494Sgshapiro 2366494Sgshapiro Make sure that the program does not generate output beyond a 2466494Sgshapiro status message (corresponding to the exit status). This may 2566494Sgshapiro require a wrapper around the actual program to redirect output 2666494Sgshapiro to /dev/null. 2766494Sgshapiro 2866494Sgshapiro Such a problem has been reported for bulk_mailer. 2966494Sgshapiro 3038032Speter* Null bytes are not handled properly in headers. 3138032Speter 3238032Speter Sendmail should handle full binary data. As it stands, it handles 3338032Speter all values in the body, but only 0x01-0x80 and 0xA0-0xFF in 3438032Speter the header. Notably missing is 0x00, which would require a major 3538032Speter restructuring of the code -- for example, almost no C library support 3638032Speter could be used to handle strings. 3738032Speter 3880785Sgshapiro* Header checks are not called if header value is too long. 3980785Sgshapiro 4080785Sgshapiro If the value of a header is longer than 1250 (MAXNAME + MAXATOM - 6) 4180785Sgshapiro characters or it contains a single word longer than 256 (MAXNAME) 4280785Sgshapiro characters then no header check is done even if one is configured for 4380785Sgshapiro the header. 4480785Sgshapiro 4538032Speter* Duplicate error messages. 4638032Speter 4738032Speter Sometimes identical, duplicate error messages can be generated. As 4838032Speter near as I can tell, this is rare and relatively innocuous. 4938032Speter 5038032Speter* $c (hop count) macro improperly set. 5138032Speter 5238032Speter The $c macro is supposed to contain the current hop count, for use 5338032Speter when calling a mailer. This macro is initialized too early, and 5438032Speter is always zero (or the value of the -c command line flag, if any). 5538032Speter This macro will probably be removed entirely in a future release; 5638032Speter I don't believe there are any mailers left that require it. 5738032Speter 5838032Speter* \231 considered harmful. 5938032Speter 6038032Speter Header addresses that have the \231 character (and possibly others 6138032Speter in the range \201 - \237) behave in odd and usually unexpected ways. 6238032Speter 6338032Speter* accept() problem on SVR4. 6438032Speter 6538032Speter Apparently, the sendmail daemon loop (doing accept()s on the network) 6638032Speter can get into a weird state on SVR4; it starts logging ``SYSERR: 6738032Speter getrequests: accept: Protocol Error''. The workaround is to kill 6838032Speter and restart the sendmail daemon. We don't have an SVR4 system at 6938032Speter Berkeley that carries more than token mail load, so I can't validate 7038032Speter this. It is likely to be a glitch in the sockets emulation, since 7138032Speter "Protocol Error" is not possible error code with Berkeley TCP/IP. 7238032Speter 7338032Speter I've also had someone report the message ``sendmail: accept: 7438032Speter SIOCGPGRP failed errno 22'' on an SVR4 system. This message is 7538032Speter not in the sendmail source code, so I assume it is also a bug 7638032Speter in the sockets emulation. (Errno 22 is EINVAL "Invalid Argument" 7738032Speter on all the systems I have available, including Solaris 2.x.) 7838032Speter Apparently, this problem is due to linking -lc before -lsocket; 7938032Speter if you are having this problem, check your Makefile. 8038032Speter 8138032Speter* accept() problem on Linux. 8238032Speter 8342575Speter The accept() in sendmail daemon loop can return ETIMEDOUT. An 8442575Speter error is reported to syslog: 8538032Speter 8638032Speter Jun 9 17:14:12 hostname sendmail[207]: NOQUEUE: SYSERR(root): 8738032Speter getrequests: accept: Connection timed out 8838032Speter 8938032Speter "Connection timed out" is not documented as a valid return from 9038032Speter accept(2) and this was believed to be a bug in the Linux kernel. 9138032Speter Later information from the Linux kernel group states that Linux 9238032Speter 2.0 kernels follow RFC1122 while sendmail follows the original BSD 9338032Speter (now POSIX 1003.1g draft) specification. The 2.1.X and later kernels 9438032Speter will follow the POSIX draft. 9538032Speter 9638032Speter* Excessive mailing list nesting can run out of file descriptors. 9738032Speter 9838032Speter If you have a mailing list that includes lots of other mailing 9938032Speter lists, each of which has a separate owner, you can run out of 10038032Speter file descriptors. Each mailing list with a separate owner uses 10138032Speter one open file descriptor (prior to 8.6.6 it was three open 10238032Speter file descriptors per list). This is particularly egregious if 10338032Speter you have your connection cache set to be large. 10438032Speter 10538032Speter* Connection caching breaks if you pass the port number as an argument. 10638032Speter 10738032Speter If you have a definition such as: 10838032Speter 10938032Speter Mport, P=[IPC], F=kmDFMuX, S=11/31, R=21, 11038032Speter M=2100000, T=DNS/RFC822/SMTP, 11138032Speter A=IPC [127.0.0.1] $h 11238032Speter 11338032Speter (i.e., where $h is the port number instead of the host name) the 11438032Speter connection caching code will break because it won't notice that 11538032Speter two messages addressed to different ports should use different 11638032Speter connections. 11738032Speter 11838032Speter* ESMTP SIZE underestimates the size of a message 11938032Speter 12038032Speter Sendmail makes no allowance for headers that it adds, nor does it 12138032Speter account for the SMTP on-the-wire \r\n expansion. It probably doesn't 12238032Speter allow for 8->7 bit MIME conversions either. 12338032Speter 12438032Speter* Paths to programs being executed and the mode of program files are 12538032Speter not checked. Essentially, the RunProgramInUnsafeDirPath and 12638032Speter RunWritableProgram bits in the DontBlameSendmail option are always 12738032Speter set. This is not a problem if your system is well managed (that is, 12838032Speter if binaries and system directories are mode 755 instead of something 12938032Speter foolish like 777). 13038032Speter 13138032Speter* 8-bit data in GECOS field 13238032Speter 13338032Speter If the GECOS (personal name) information in the passwd file contains 13438032Speter 8-bit characters, those characters can be included in the message 13538032Speter header, which can cause problems when sending SMTP to hosts that 13638032Speter only accept 7-bit characters. 13738032Speter 13838032Speter* 8->7 bit MIME conversion 13938032Speter 14038032Speter When sendmail is doing 8->7 bit MIME conversions, and the message 14138032Speter contains certain MIME body types that cannot be converted to 7-bit, 14238032Speter sendmail will strip the message to 7-bit. 14338032Speter 14438032Speter* 7->8 bit MIME conversion 14538032Speter 14638032Speter If a message that is encoded as 7-bit MIME is converted to 8-bit and 14738032Speter that message when decoded is illegal (e.g., because of long lines or 14838032Speter illegal characters), sendmail can produce an illegal message. 14938032Speter 15038032Speter* MIME encoded full name phrases in the From: header 15138032Speter 15264562Sgshapiro If a full name phrase includes characters from MustQuoteChars, sendmail 15364562Sgshapiro will quote the entire full name phrase. If MustQuoteChars includes 15464562Sgshapiro characters which are not special characters according to STD 11 (RFC 15564562Sgshapiro 822), this quotation can interfere with MIME encoded full name phrases. 15638032Speter By default, sendmail includes the single quote character (') in 15738032Speter MustQuoteChars even though it is not listed as a special character in 15838032Speter STD 11. 15938032Speter 16042575Speter* bestmx map with -z flag truncates the list of MX hosts 16138032Speter 16242575Speter A bestmx map configured with the -z flag will truncate the list 16342575Speter of MX hosts. This prevents creation of strings which are too 16442575Speter long for ruleset parsing. This can have an adverse effect on the 16542575Speter relay_based_on_MX feature. 16642575Speter 16743730Speter* Saving to ~sender/dead.letter fails if su'ed to root 16842575Speter 16943730Speter If ErrorMode is set to print and an error in sending mail occurs, 17043730Speter the normal action is to print a message to the screen and append 17143730Speter the message to a dead.letter file in the sender's home directory. 17243730Speter In the case where the sender is using su to act as root, the file 17343730Speter safety checks prevent sendmail from saving the dead.letter file 17443730Speter because the sender's uid and the current real uid do not match. 17564562Sgshapiro 17643730Speter* Berkeley DB 2.X race condition with fcntl() locking 17743730Speter 17843730Speter There is a race condition for Berkeley DB 2.X databases on 17943730Speter operating systems which use fcntl() style locking, such as 18043730Speter Solaris. Sendmail locks the map before calling db_open() to 18143730Speter prevent others from modifying the map while it is being opened. 18243730Speter Unfortunately, Berkeley DB opens the map, closes it, and then 18343730Speter reopens it. fcntl() locking drops the lock when any file 18443730Speter descriptor pointing to the file is closed, even if it is a 18543730Speter different file descriptor than the one used to initially lock 18643730Speter the file. As a result there is a possibility that entries in a 18743730Speter map might not be found during a map rebuild. As a workaround, 18843730Speter you can use makemap to build a map with a new name and then 18943730Speter "mv" the new db file to replace the old one. 19043730Speter 19164562Sgshapiro Sleepycat Software has added code to avoid this race condition to 19264562Sgshapiro Berkeley DB versions after 2.7.5. 19364562Sgshapiro 19443730Speter* File open timeouts not available on hard mounted NFS file systems 19543730Speter 19643730Speter Since SIGALRM does not interrupt an RPC call for hard mounted 19743730Speter NFS file systems, it is impossible to implement a timeout on a file 19843730Speter open operation. Therefore, while the NFS server is not responding, 19943730Speter attempts to open a file on that server will hang. Systems with 20043730Speter local mail delivery and NFS hard mounted home directories should be 20143730Speter avoided, as attempts to open the forward files could hang. 20243730Speter 20380785Sgshapiro* Race condition for delivery to set-user-id files 20464562Sgshapiro 20564562Sgshapiro Sendmail will deliver to a fail if the file is owned by the DefaultUser 20680785Sgshapiro or has the set-user-id bit set. Unfortunately, some systems clear that bit 20764562Sgshapiro when a file is modified. Sendmail compensates by resetting the file mode 20864562Sgshapiro back to it's original settings. Unfortunately, there's still a 20964562Sgshapiro permission failure race as sendmail checks the permissions before locking 21064562Sgshapiro the file. This is unavoidable as sendmail must verify the file is safe 21164562Sgshapiro to open before opening it. A file can not be locked until it is open. 21264562Sgshapiro 21364562Sgshapiro* Potential denial of service attack with AutoRebuildAliases 21464562Sgshapiro 21564562Sgshapiro There is a potential for a denial of service attack if the 21664562Sgshapiro AutoRebuildAliases option is set as a user can kill the sendmail process 21764562Sgshapiro while it is rebuilding the aliases file leaving it in an inconsistent 21864562Sgshapiro state. This option and it's use is deprecated and will be removed from a 21964562Sgshapiro future version of sendmail. 22064562Sgshapiro 22180785Sgshapiro$Revision: 8.43.16.2 $, Last updated $Date: 2001/07/31 22:42:46 $ 222