Attachment 3098 Details for Bug 1844 – Force file and directory permissions for internal-sftp with parameter -m

[patch] Force file and directory permissions for internal-sftp with parameter -m

openssh-force-permission-v4.patch (text/plain), 4.49 KB, created by Dr. Nagy Elemér Károly on 2017-11-26 07:36:35 AEDT

(hide)

Description:

Filename:

MIME Type:

Creator: Dr. Nagy Elemér Károly

Created: 2017-11-26 07:36:35 AEDT

Size: 4.49 KB

patch

obsolete

># Patch for openssh: "Explicit file permissions enhancement to sftp-server"
># See https://bugzilla.mindrot.org/show_bug.cgi?id=1844
># Tested on: Debian openssh-server 1:7.4p1-10+deb9u1, Debian openssh-server 1:7.6p1-2
># Changelog, authors:
># 2010-12-10 - Rob Candland - v1 - public domain - Force file permissions for sftp-server
># 2016-09-09 - Rob Candland, Jakub Jelen - v2 - public domain - patch with proper umask restore
># 2017-11-24 - Rob Candland, Jakub Jelen, Dr. Nagy ElemÃ©r KÃ¡roly - v3 - public domain - Force directory permissions as well
># 2017-11-25 - Rob Candland, Jakub Jelen, Dr. Nagy ElemÃ©r KÃ¡roly - v4 - public domain - fix documentation
>diff -u original/sftp-server.8 patched/sftp-server.8
>--- original/sftp-server.8	2016-12-19 04:59:41.000000000 +0000
>+++ patched/sftp-server.8	2017-11-23 08:47:01.267239186 +0000
>@@ -38,6 +38,7 @@
> .Op Fl P Ar blacklisted_requests
> .Op Fl p Ar whitelisted_requests
> .Op Fl u Ar umask
>+.Op Fl m Ar force_file_dir_perms
> .Ek
> .Nm
> .Fl Q Ar protocol_feature
>@@ -138,6 +139,10 @@
> .Xr umask 2
> to be applied to newly-created files and directories, instead of the
> user's default mask.
>+.It Fl m Ar force_file_dir_perms
>+Sets explicit permissions to be applied to newly-created files and directories
>+instead of the default or client requested mode.  Numeric values include:
>+777, 755, 750, 666, 644, 640, etc.  Option -u is ineffective if -m is set.
> .El
> .Pp
> On some systems,
>diff -u original/sftp-server.c patched/sftp-server.c
>--- original/sftp-server.c	2016-12-19 04:59:41.000000000 +0000
>+++ patched/sftp-server.c	2017-11-23 13:07:08.481765581 +0000
>@@ -65,6 +65,10 @@
> /* Version of client */
> static u_int version;
> 
>+/* Force file and directory permissions */
>+int permforce = 0;
>+long permforcemode;
>+
> /* SSH2_FXP_INIT received */
> static int init_done;
> 
>@@ -679,6 +683,7 @@
> 	Attrib a;
> 	char *name;
> 	int r, handle, fd, flags, mode, status = SSH2_FX_FAILURE;
>+	mode_t old_umask = 0;
> 
> 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
> 	    (r = sshbuf_get_u32(iqueue, &pflags)) != 0 || /* portable flags */
>@@ -688,6 +693,10 @@
> 	debug3("request %u: open flags %d", id, pflags);
> 	flags = flags_from_portable(pflags);
> 	mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a.perm : 0666;
>+	if (permforce == 1) {   /* Force perm if -m is set */
>+		mode = permforcemode;
>+		old_umask = umask(0); /* so umask does not interfere */
>+	}
> 	logit("open \"%s\" flags %s mode 0%o",
> 	    name, string_from_portable(pflags), mode);
> 	if (readonly &&
>@@ -709,6 +718,8 @@
> 			}
> 		}
> 	}
>+	if (permforce == 1)
>+		(void) umask(old_umask); /* restore umask to something sane */
> 	if (status != SSH2_FX_OK)
> 		send_status(id, status);
> 	free(name);
>@@ -1110,6 +1121,7 @@
> 	Attrib a;
> 	char *name;
> 	int r, mode, status = SSH2_FX_FAILURE;
>+	mode_t old_umask = 0;
> 
> 	if ((r = sshbuf_get_cstring(iqueue, &name, NULL)) != 0 ||
> 	    (r = decode_attrib(iqueue, &a)) != 0)
>@@ -1117,9 +1129,16 @@
> 
> 	mode = (a.flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ?
> 	    a.perm & 07777 : 0777;
>+	if (permforce == 1) {   /* Force perm if -m is set */
>+		mode = permforcemode;
>+		old_umask = umask(0); /* so umask does not interfere */
>+	}
>+
> 	debug3("request %u: mkdir", id);
> 	logit("mkdir name \"%s\" mode 0%o", name, mode);
> 	r = mkdir(name, mode);
>+        if (permforce == 1)
>+                (void) umask(old_umask); /* restore umask to something sane */
> 	status = (r == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
> 	send_status(id, status);
> 	free(name);
>@@ -1490,7 +1509,7 @@
> 	fprintf(stderr,
> 	    "usage: %s [-ehR] [-d start_directory] [-f log_facility] "
> 	    "[-l log_level]\n\t[-P blacklisted_requests] "
>-	    "[-p whitelisted_requests] [-u umask]\n"
>+	    "[-p whitelisted_requests] [-u umask] [-m force_file_dir_perms]\n"
> 	    "       %s -Q protocol_feature\n",
> 	    __progname, __progname);
> 	exit(1);
>@@ -1516,7 +1535,7 @@
> 	pw = pwcopy(user_pw);
> 
> 	while (!skipargs && (ch = getopt(argc, argv,
>-	    "d:f:l:P:p:Q:u:cehR")) != -1) {
>+	    "d:f:l:P:p:Q:u:m:cehR")) != -1) {
> 		switch (ch) {
> 		case 'Q':
> 			if (strcasecmp(optarg, "requests") != 0) {
>@@ -1576,6 +1595,15 @@
> 				fatal("Invalid umask \"%s\"", optarg);
> 			(void)umask((mode_t)mask);
> 			break;
>+		case 'm':
>+			/* Force permissions on file and directory received via sftp */
>+			permforce = 1;
>+			permforcemode = strtol(optarg, &cp, 8);
>+			if (permforcemode < 0 || permforcemode > 0777 ||
>+			    *cp != '\0' || (permforcemode == 0 &&
>+			    errno != 0))
>+				fatal("Invalid file mode \"%s\"", optarg);
>+			break;
> 		case 'h':
> 		default:
> 			sftp_server_usage();

Actions: View | Diff

Attachments on bug 1844: 1973 | 2547 | 2872 | 3096 | 3098