215 lines
9.2 KiB
Plaintext
215 lines
9.2 KiB
Plaintext
|
|
|
|
K N O W N B U G S I N S E N D M A I L
|
|
|
|
|
|
The following are bugs or deficiencies in sendmail that I am aware of
|
|
but which have not been fixed in the current release. You probably
|
|
want to get the most up to date version of this from ftp.sendmail.org
|
|
in /pub/sendmail/KNOWNBUGS. For descriptions of bugs that have been
|
|
fixed, see the file RELEASE_NOTES (in the root directory of the sendmail
|
|
distribution).
|
|
|
|
This list is not guaranteed to be complete.
|
|
|
|
* Delivery to programs that generate too much output may cause problems
|
|
(8.10, 8.11)
|
|
|
|
If e-mail is delivered to a program which generates too much
|
|
output, then sendmail may issue an error:
|
|
|
|
timeout waiting for input from local during Draining Input
|
|
|
|
Make sure that the program does not generate output beyond a
|
|
status message (corresponding to the exit status). This may
|
|
require a wrapper around the actual program to redirect output
|
|
to /dev/null.
|
|
|
|
Such a problem has been reported for bulk_mailer.
|
|
|
|
* Null bytes are not handled properly in headers.
|
|
|
|
Sendmail should handle full binary data. As it stands, it handles
|
|
all values in the body, but only 0x01-0x80 and 0xA0-0xFF in
|
|
the header. Notably missing is 0x00, which would require a major
|
|
restructuring of the code -- for example, almost no C library support
|
|
could be used to handle strings.
|
|
|
|
* Duplicate error messages.
|
|
|
|
Sometimes identical, duplicate error messages can be generated. As
|
|
near as I can tell, this is rare and relatively innocuous.
|
|
|
|
* $c (hop count) macro improperly set.
|
|
|
|
The $c macro is supposed to contain the current hop count, for use
|
|
when calling a mailer. This macro is initialized too early, and
|
|
is always zero (or the value of the -c command line flag, if any).
|
|
This macro will probably be removed entirely in a future release;
|
|
I don't believe there are any mailers left that require it.
|
|
|
|
* \231 considered harmful.
|
|
|
|
Header addresses that have the \231 character (and possibly others
|
|
in the range \201 - \237) behave in odd and usually unexpected ways.
|
|
|
|
* accept() problem on SVR4.
|
|
|
|
Apparently, the sendmail daemon loop (doing accept()s on the network)
|
|
can get into a weird state on SVR4; it starts logging ``SYSERR:
|
|
getrequests: accept: Protocol Error''. The workaround is to kill
|
|
and restart the sendmail daemon. We don't have an SVR4 system at
|
|
Berkeley that carries more than token mail load, so I can't validate
|
|
this. It is likely to be a glitch in the sockets emulation, since
|
|
"Protocol Error" is not possible error code with Berkeley TCP/IP.
|
|
|
|
I've also had someone report the message ``sendmail: accept:
|
|
SIOCGPGRP failed errno 22'' on an SVR4 system. This message is
|
|
not in the sendmail source code, so I assume it is also a bug
|
|
in the sockets emulation. (Errno 22 is EINVAL "Invalid Argument"
|
|
on all the systems I have available, including Solaris 2.x.)
|
|
Apparently, this problem is due to linking -lc before -lsocket;
|
|
if you are having this problem, check your Makefile.
|
|
|
|
* accept() problem on Linux.
|
|
|
|
The accept() in sendmail daemon loop can return ETIMEDOUT. An
|
|
error is reported to syslog:
|
|
|
|
Jun 9 17:14:12 hostname sendmail[207]: NOQUEUE: SYSERR(root):
|
|
getrequests: accept: Connection timed out
|
|
|
|
"Connection timed out" is not documented as a valid return from
|
|
accept(2) and this was believed to be a bug in the Linux kernel.
|
|
Later information from the Linux kernel group states that Linux
|
|
2.0 kernels follow RFC1122 while sendmail follows the original BSD
|
|
(now POSIX 1003.1g draft) specification. The 2.1.X and later kernels
|
|
will follow the POSIX draft.
|
|
|
|
* Excessive mailing list nesting can run out of file descriptors.
|
|
|
|
If you have a mailing list that includes lots of other mailing
|
|
lists, each of which has a separate owner, you can run out of
|
|
file descriptors. Each mailing list with a separate owner uses
|
|
one open file descriptor (prior to 8.6.6 it was three open
|
|
file descriptors per list). This is particularly egregious if
|
|
you have your connection cache set to be large.
|
|
|
|
* Connection caching breaks if you pass the port number as an argument.
|
|
|
|
If you have a definition such as:
|
|
|
|
Mport, P=[IPC], F=kmDFMuX, S=11/31, R=21,
|
|
M=2100000, T=DNS/RFC822/SMTP,
|
|
A=IPC [127.0.0.1] $h
|
|
|
|
(i.e., where $h is the port number instead of the host name) the
|
|
connection caching code will break because it won't notice that
|
|
two messages addressed to different ports should use different
|
|
connections.
|
|
|
|
* ESMTP SIZE underestimates the size of a message
|
|
|
|
Sendmail makes no allowance for headers that it adds, nor does it
|
|
account for the SMTP on-the-wire \r\n expansion. It probably doesn't
|
|
allow for 8->7 bit MIME conversions either.
|
|
|
|
* Paths to programs being executed and the mode of program files are
|
|
not checked. Essentially, the RunProgramInUnsafeDirPath and
|
|
RunWritableProgram bits in the DontBlameSendmail option are always
|
|
set. This is not a problem if your system is well managed (that is,
|
|
if binaries and system directories are mode 755 instead of something
|
|
foolish like 777).
|
|
|
|
* 8-bit data in GECOS field
|
|
|
|
If the GECOS (personal name) information in the passwd file contains
|
|
8-bit characters, those characters can be included in the message
|
|
header, which can cause problems when sending SMTP to hosts that
|
|
only accept 7-bit characters.
|
|
|
|
* 8->7 bit MIME conversion
|
|
|
|
When sendmail is doing 8->7 bit MIME conversions, and the message
|
|
contains certain MIME body types that cannot be converted to 7-bit,
|
|
sendmail will strip the message to 7-bit.
|
|
|
|
* 7->8 bit MIME conversion
|
|
|
|
If a message that is encoded as 7-bit MIME is converted to 8-bit and
|
|
that message when decoded is illegal (e.g., because of long lines or
|
|
illegal characters), sendmail can produce an illegal message.
|
|
|
|
* MIME encoded full name phrases in the From: header
|
|
|
|
If a full name phrase includes characters from MustQuoteChars, sendmail
|
|
will quote the entire full name phrase. If MustQuoteChars includes
|
|
characters which are not special characters according to STD 11 (RFC
|
|
822), this quotation can interfere with MIME encoded full name phrases.
|
|
By default, sendmail includes the single quote character (') in
|
|
MustQuoteChars even though it is not listed as a special character in
|
|
STD 11.
|
|
|
|
* bestmx map with -z flag truncates the list of MX hosts
|
|
|
|
A bestmx map configured with the -z flag will truncate the list
|
|
of MX hosts. This prevents creation of strings which are too
|
|
long for ruleset parsing. This can have an adverse effect on the
|
|
relay_based_on_MX feature.
|
|
|
|
* Saving to ~sender/dead.letter fails if su'ed to root
|
|
|
|
If ErrorMode is set to print and an error in sending mail occurs,
|
|
the normal action is to print a message to the screen and append
|
|
the message to a dead.letter file in the sender's home directory.
|
|
In the case where the sender is using su to act as root, the file
|
|
safety checks prevent sendmail from saving the dead.letter file
|
|
because the sender's uid and the current real uid do not match.
|
|
|
|
* Berkeley DB 2.X race condition with fcntl() locking
|
|
|
|
There is a race condition for Berkeley DB 2.X databases on
|
|
operating systems which use fcntl() style locking, such as
|
|
Solaris. Sendmail locks the map before calling db_open() to
|
|
prevent others from modifying the map while it is being opened.
|
|
Unfortunately, Berkeley DB opens the map, closes it, and then
|
|
reopens it. fcntl() locking drops the lock when any file
|
|
descriptor pointing to the file is closed, even if it is a
|
|
different file descriptor than the one used to initially lock
|
|
the file. As a result there is a possibility that entries in a
|
|
map might not be found during a map rebuild. As a workaround,
|
|
you can use makemap to build a map with a new name and then
|
|
"mv" the new db file to replace the old one.
|
|
|
|
Sleepycat Software has added code to avoid this race condition to
|
|
Berkeley DB versions after 2.7.5.
|
|
|
|
* File open timeouts not available on hard mounted NFS file systems
|
|
|
|
Since SIGALRM does not interrupt an RPC call for hard mounted
|
|
NFS file systems, it is impossible to implement a timeout on a file
|
|
open operation. Therefore, while the NFS server is not responding,
|
|
attempts to open a file on that server will hang. Systems with
|
|
local mail delivery and NFS hard mounted home directories should be
|
|
avoided, as attempts to open the forward files could hang.
|
|
|
|
* Race condition for delivery to setuid files
|
|
|
|
Sendmail will deliver to a fail if the file is owned by the DefaultUser
|
|
or has the setuid bit set. Unfortunately, some systems clear that bit
|
|
when a file is modified. Sendmail compensates by resetting the file mode
|
|
back to it's original settings. Unfortunately, there's still a
|
|
permission failure race as sendmail checks the permissions before locking
|
|
the file. This is unavoidable as sendmail must verify the file is safe
|
|
to open before opening it. A file can not be locked until it is open.
|
|
|
|
* Potential denial of service attack with AutoRebuildAliases
|
|
|
|
There is a potential for a denial of service attack if the
|
|
AutoRebuildAliases option is set as a user can kill the sendmail process
|
|
while it is rebuilding the aliases file leaving it in an inconsistent
|
|
state. This option and it's use is deprecated and will be removed from a
|
|
future version of sendmail.
|
|
|
|
$Revision: 8.43.16.1 $, Last updated $Date: 2000/09/28 00:45:37 $
|