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Cygwin: pipes: call nt_create with handle references 

...to avoid potential pointer mishandling.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2021-09-03 10:57:21 +02:00
parent 8653eb1df3
commit ea9c0bbedc
1 changed files with 23 additions and 32 deletions
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55
winsup/cygwin/fhandler_pipe.cc
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@ -660,7 +660,7 @@ fhandler_pipe::create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w,
simplicity, nt_create will omit the 'open_mode' and 'name' simplicity, nt_create will omit the 'open_mode' and 'name'
parameters, which aren't needed for our purposes. */ parameters, which aren't needed for our purposes. */
static int nt_create (LPSECURITY_ATTRIBUTES, PHANDLE, PHANDLE, DWORD, static int nt_create (LPSECURITY_ATTRIBUTES, HANDLE &, HANDLE &, DWORD,
int64_t *); int64_t *);
int int
@ -671,7 +671,7 @@ fhandler_pipe::create (fhandler_pipe *fhs[2], unsigned psize, int mode)
int res = -1; int res = -1;
int64_t unique_id; int64_t unique_id;
int ret = nt_create (sa, &r, &w, psize, &unique_id); int ret = nt_create (sa, r, w, psize, &unique_id);
if (ret) if (ret)
__seterrno_from_win_error (ret); __seterrno_from_win_error (ret);
else if ((fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev)) == NULL) else if ((fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev)) == NULL)
@ -718,7 +718,7 @@ fhandler_pipe::create (fhandler_pipe *fhs[2], unsigned psize, int mode)
} }
static int static int
nt_create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w, nt_create (LPSECURITY_ATTRIBUTES sa_ptr, HANDLE &r, HANDLE &w,
DWORD psize, int64_t *unique_id) DWORD psize, int64_t *unique_id)
{ {
NTSTATUS status; NTSTATUS status;
@ -729,10 +729,8 @@ nt_create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w,
LARGE_INTEGER timeout; LARGE_INTEGER timeout;
/* Default to error. */ /* Default to error. */
if (r) r = NULL;
*r = NULL; w = NULL;
if (w)
*w = NULL;
status = fhandler_base::npfs_handle (npfsh); status = fhandler_base::npfs_handle (npfsh);
if (!NT_SUCCESS (status)) if (!NT_SUCCESS (status))
@ -760,7 +758,7 @@ nt_create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w,
Retrying will probably never be necessary, but we want Retrying will probably never be necessary, but we want
to be as robust as possible. */ to be as robust as possible. */
DWORD err = 0; DWORD err = 0;
while (r && !*r) while (!r)
{ {
static volatile ULONG pipe_unique_id; static volatile ULONG pipe_unique_id;
LONG id = InterlockedIncrement ((LONG *) &pipe_unique_id); LONG id = InterlockedIncrement ((LONG *) &pipe_unique_id);
@ -779,7 +777,7 @@ nt_create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w,
npfsh, sa_ptr->lpSecurityDescriptor); npfsh, sa_ptr->lpSecurityDescriptor);
timeout.QuadPart = -500000; timeout.QuadPart = -500000;
status = NtCreateNamedPipeFile (r, access, &attr, &io, status = NtCreateNamedPipeFile (&r, access, &attr, &io,
FILE_SHARE_READ | FILE_SHARE_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE,
FILE_CREATE, 0, pipe_type, FILE_CREATE, 0, pipe_type,
FILE_PIPE_BYTE_STREAM_MODE, FILE_PIPE_BYTE_STREAM_MODE,
@ -787,7 +785,7 @@ nt_create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w,
if (NT_SUCCESS (status)) if (NT_SUCCESS (status))
{ {
debug_printf ("pipe read handle %p", *r); debug_printf ("pipe read handle %p", r);
err = 0; err = 0;
break; break;
} }
@ -800,49 +798,42 @@ nt_create (LPSECURITY_ATTRIBUTES sa_ptr, PHANDLE r, PHANDLE w,
/* The pipe is already open with compatible parameters. /* The pipe is already open with compatible parameters.
Pick a new name and retry. */ Pick a new name and retry. */
debug_printf ("pipe busy, retrying"); debug_printf ("pipe busy, retrying");
*r = NULL; r = NULL;
break; break;
case STATUS_ACCESS_DENIED: case STATUS_ACCESS_DENIED:
/* The pipe is already open with incompatible parameters. /* The pipe is already open with incompatible parameters.
Pick a new name and retry. */ Pick a new name and retry. */
debug_printf ("pipe access denied, retrying"); debug_printf ("pipe access denied, retrying");
*r = NULL; r = NULL;
break; break;
default: default:
{ {
__seterrno_from_nt_status (status); __seterrno_from_nt_status (status);
err = GetLastError (); err = GetLastError ();
debug_printf ("failed, %E"); debug_printf ("failed, %E");
*r = INVALID_HANDLE_VALUE; r = INVALID_HANDLE_VALUE;
} }
} }
} }
if (err) if (err)
{ {
*r = NULL; r = NULL;
return err; return err;
} }
if (!w) debug_printf ("NtOpenFile: name %S", &pipename);
debug_printf ("pipe write handle NULL");
else access = GENERIC_WRITE | FILE_READ_ATTRIBUTES | SYNCHRONIZE;
status = NtOpenFile (&w, access, &attr, &io, 0, 0);
if (!NT_SUCCESS (status))
{ {
debug_printf ("NtOpenFile: name %S", &pipename); DWORD err = GetLastError ();
debug_printf ("NtOpenFile failed, r %p, %E", r);
access = GENERIC_WRITE | FILE_READ_ATTRIBUTES | SYNCHRONIZE; if (r)
status = NtOpenFile (w, access, &attr, &io, 0, 0); NtClose (r);
if (!NT_SUCCESS (status)) w = NULL;
{ return err;
DWORD err = GetLastError ();
debug_printf ("NtOpenFile failed, r %p, %E", r);
if (r)
NtClose (*r);
*w = NULL;
return err;
}
debug_printf ("pipe write handle %p", *w);
} }
/* Success. */ /* Success. */