On certain error conditions there is a code snippet that checks
whether the last component of the path has a trailing dot or space or
a leading space. Skip this check if the last component is empty,
i.e., if the path ends with a backslash. This avoids an assertion
failure if the trailing backslash is the only backslash in the path,
as is the case for a DOS drive 'X:\'.
Addresses: https://cygwin.com/ml/cygwin/2019-12/msg00016.html
- Pseudo console clears console screen buffer if ESC[?3h or ESC[?3l
is sent. However, xterm/vt100 does not clear screen. This cause
mismatch between real screen and console screen buffer. Therefore,
this patch triggers redraw screen in that situation so that the
synchronization is done on the next execution of native app.
This solves the problem reported in:
https://www.cygwin.com/ml/cygwin-patches/2019-q4/msg00116.html
- Previously, pty cleared screen at startup for synchronization
between the real screen and console screen buffer for pseudo
console. With this patch, instead of clearing screen, the screen
is redrawn when the first native program is executed after pty
is created. In other words, synchronization is deferred until
the native app is executed. Moreover, this realizes excluding
$TERM dependent code.
fhandler_console::create_invisible_console_workaround() does not use the
lpApplicationName parameter and neglects to quote its command name on
lpCommandLine in the call to CreateProcessW.
Given CreateProcessW's brain-dead method to evaluate the application
path given on the command line, this opens up a security problem if
Cygwin is installed into a path with spaces in it.
Fix this by using the lpApplicationName parameter and quoting of the
application path in the lpCommandLine parameter (used as argv[0] in
the called console helper.
For extended paranoia, make the argument string array big enough to
fit full 64 bit pointer values into it. Handles usually only use
the lower 32 bit, but better safe than sorry.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
FH_CONS_MAX should refelect the fact that we allow 128 consoles, even if
it's unused.
Suggested-by: Achim Gratz <Stromeko@nexgo.de>
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Commit 5a0f2c00aa "Cygwin: fork/exec: fix child process permissions"
removed the PROCESS_DUP_HANDLE handle permission of the parent process
handle in the child to avoid a security problem.
It turned out that this broke the following scenario: If a process forks
and then the parent execs, the child loses the ability to register the
parent's death. To wit, after the parent died the child process does
not set its own PPID to 1 anymore.
The current exec mechanism copies required handle values (handles to
keep contact to the child processes) into the child_info for the
about-to-be-exec'ed process. The exec'ed process is supposed to
duplicate these handles. This fails, given that we don't allow the
exec'ed process PROCESS_DUP_HANDLE access to the exec'ing process since
commit 5a0f2c00aa.
The fix is to avoid the DuplicateHandle calls in the exec'ed process.
This patch sets the affected handles to "inheritable" in the exec'ing
process at exec time. The exec'ed process just copies the handle values
and resets handle inheritance to "non-inheritable". The exec'ing
process doesn't have to reset handle inheritance, it exits after setting
up the exec'ed process anyway.
Testcase: $ ssh-agent /bin/sleep 3
ssh-agent forks and the parent exec's sleep. After sleep exits, `ps'
should show ssh-agent to have PPID 1, and eventually ssh-agent exits.
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
Call find_exec with the FE_NNF flag to enforce a NULL return when the
executable isn't found in $PATH. Convert NULL to "". This aligns
spawnvp and spawnvpe with execvp and execvpe.
If the directory name has the form 'x:' followed by one or more
slashes or backslashes, and if there's at least one backslash, assume
that the user is referring to 'x:\', the root directory of drive x,
and don't strip the backslash.
Previously all trailing slashes and backslashes were stripped, and the
name was treated as a relative file name containing a literal colon.
Addresses https://cygwin.com/ml/cygwin/2019-08/msg00334.html.
Add feature test print macro that makes feature, bit, and flag text
comparison and checking easier. Handle as common former Intel only
feature flags also supported on AMD. Change order and some flag names
to agree with current Linux.
If the source path starts with the Win32 long path prefix '\\?\' or
the NT object directory prefix '\??\', require the prefix to be
followed by 'UNC\' or '<drive letter>:\'. Otherwise return EINVAL.
This fixes the assertion failure in symlink_info::check that was
reported here:
https://cygwin.com/ml/cygwin/2019-09/msg00228.html
That assertion failure was caused by normalize_win32_path returning a
path with no backslashes when the source path was '\\?\DRIVE'.
If the last component of the directory name is a symlink followed by a
slash, rmdir now fails, following Linux but not POSIX, even if the
symlink resolves to an existing empty directory.
mkdir was similarly changed in 2009 in commit
52dba6a5c4. Modify a comment to clarify
the purpose of that commit.
Addresses https://cygwin.com/ml/cygwin/2019-09/msg00221.html.
Prior to commit b0717aae, path_conv::check had the following code:
if (strncmp (path, "\\\\.\\", 4))
{
/* Windows ignores trailing dots and spaces in the last path
component, and ignores exactly one trailing dot in inner
path components. */
char *tail = NULL;
[...]
if (!tail || tail == path)
/* nothing */;
else if (tail[-1] != '\\')
{
*tail = '\0';
[...]
}
Commit b0717aae0 intended to disable this code, but it inadvertently
disabled only part of it. In particular, the declaration of the local
tail variable was in the disabled code, but the following remained:
if (!tail || tail == path)
/* nothing */;
else if (tail[-1] != '\\')
{
*tail = '\0';
[...]
}
[A later commit removed the disabled code.]
The tail variable here points into a string different from path,
causing that string to be truncated under some circumstances. See
https://cygwin.com/ml/cygwin/2019-09/msg00001.html
for more details.
This commit fixes the problem by removing the leftover code
that was intended to be removed in b0717aae.
Ken Brown
Anton Lavrentiev via cygwin-patches
Takashi Yano
Brian Inglis
Mark Geisert
Corinna Vinschen
Achim Gratz