From afccae852f231e8982276fa53614b3dc999b6bf8 Mon Sep 17 00:00:00 2001

From: Pavel Shilovsky <pshilov@microsoft.com>

Date: Wed, 3 Apr 2019 22:42:10 +0000

Subject: [PATCH 20/36] mount.cifs: detect GMT format of snapshot version

In order to provide an easy way to access snapshots a GMT

token string should be allowed as a "snapshot" mount option

argument, not SMB 100-nanoseconds time only. Detect if the

argument is in GMT format and convert it to SMB 100-nanoseconds

time before passing to the kernel.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>

Reviewed-by: Paulo Alcantara <palcantara@suse.de>

(cherry picked from commit c52be345de22669c53a6ec41c28914183bf65d09)

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>

---

 mount.cifs.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++-------

 1 file changed, 47 insertions(+), 7 deletions(-)

diff --git a/mount.cifs.c b/mount.cifs.c

index c6a1bd6..b3235e4 100644

--- a/mount.cifs.c

+++ b/mount.cifs.c

@@ -43,6 +43,7 @@

 #include <limits.h>

 #include <paths.h>

 #include <libgen.h>

+#include <time.h>

 #include <sys/mman.h>

 #include <sys/wait.h>

 #ifdef HAVE_SYS_FSUID_H

@@ -161,10 +162,16 @@

 #define OPT_BKUPUID    30

 #define OPT_BKUPGID    31

 #define OPT_NOFAIL     32

+#define OPT_SNAPSHOT   33

 #define MNT_TMP_FILE "/.mtab.cifs.XXXXXX"

-/* struct for holding parsed mount info for use by privleged process */

+#define GMT_NAME_LEN 24 /* length of a @GMT- name */

+#define GMT_FORMAT "@GMT-%Y.%m.%d-%H.%M.%S"

+

+#define NTFS_TIME_OFFSET ((unsigned long long)(369*365 + 89) * 24 * 3600 * 10000000)

+

+/* struct for holding parsed mount info for use by privileged process */

 struct parsed_mount_info {

 	unsigned long flags;

 	char host[NI_MAXHOST + 1];

@@ -271,9 +278,9 @@ static int mount_usage(FILE * stream)

 	fprintf(stream,

 		"\n\tcache=<strict|none|loose>,nounix,cifsacl,sec=<authentication mechanism>,");

 	fprintf(stream,

-		"\n\tsign,seal,fsc,snapshot=<time>,nosharesock,persistenthandles,resilienthandles,");

+		"\n\tsign,seal,fsc,snapshot=<token|time>,nosharesock,persistenthandles,");

 	fprintf(stream,

-		"\n\trdma,vers=<smb_dialect>,cruid");

+		"\n\tresilienthandles,rdma,vers=<smb_dialect>,cruid");

 	fprintf(stream,

 		"\n\nOptions not needed for servers supporting CIFS Unix extensions");

 	fprintf(stream,

@@ -773,6 +780,8 @@ static int parse_opt_token(const char *token)

 		return OPT_NOFAIL;

 	if (strncmp(token, "x-", 2) == 0)

 		return OPT_IGNORE;

+	if (strncmp(token, "snapshot", 8) == 0)

+		return OPT_SNAPSHOT;

 	return OPT_ERROR;

 }

@@ -793,16 +802,19 @@ parse_options(const char *data, struct parsed_mount_info *parsed_info)

 	int got_uid = 0;

 	int got_cruid = 0;

 	int got_gid = 0;

+	int got_snapshot = 0;

 	uid_t uid, cruid = 0, bkupuid = 0;

 	gid_t gid, bkupgid = 0;

 	char *ep;

 	struct passwd *pw;

 	struct group *gr;

 	/*

-	 * max 32-bit uint in decimal is 4294967295 which is 10 chars wide

-	 * +1 for NULL, and +1 for good measure

+	 * max 64-bit uint in decimal is 18446744073709551615 which is 20 chars

+	 * wide +1 for NULL, and +1 for good measure

 	 */

-	char txtbuf[12];

+	char txtbuf[22];

+	unsigned long long snapshot;

+	struct tm tm;

 	/* make sure we're starting from beginning */

 	out[0] = '\0';

@@ -1130,6 +1142,19 @@ parse_options(const char *data, struct parsed_mount_info *parsed_info)

 		case OPT_NOFAIL:

 			parsed_info->nofail = 1;

 			goto nocopy;

+		case OPT_SNAPSHOT:

+			if (!value || !*value)

+				goto nocopy;

+			if (strncmp(value, "@GMT-", 5))

+				break;

+			if ((strlen(value) != GMT_NAME_LEN) ||

+			    (strptime(value, GMT_FORMAT, &tm) == NULL)) {

+				fprintf(stderr, "bad snapshot token\n");

+				return EX_USAGE;

+			}

+			snapshot = timegm(&tm) * 10000000 + NTFS_TIME_OFFSET;

+			got_snapshot = 1;

+			goto nocopy;

 		}

 		/* check size before copying option to buffer */

@@ -1225,7 +1250,7 @@ nocopy:

 	if (got_bkupgid) {

 		word_len = snprintf(txtbuf, sizeof(txtbuf), "%u", bkupgid);

-		/* comma + "backkupgid=" + terminating NULL == 12 */

+		/* comma + "backupgid=" + terminating NULL == 12 */

 		if (out_len + word_len + 12 > MAX_OPTIONS_LEN) {

 			fprintf(stderr, "Options string too long\n");

 			return EX_USAGE;

@@ -1237,6 +1262,21 @@ nocopy:

 		}

 		snprintf(out + out_len, word_len + 11, "backupgid=%s", txtbuf);

 	}

+	if (got_snapshot) {

+		word_len = snprintf(txtbuf, sizeof(txtbuf), "%llu", snapshot);

+

+		/* comma + "snapshot=" + terminating NULL == 11 */

+		if (out_len + word_len + 11 > MAX_OPTIONS_LEN) {

+			fprintf(stderr, "Options string too long\n");

+			return EX_USAGE;

+		}

+

+		if (out_len) {

+			strlcat(out, ",", MAX_OPTIONS_LEN);

+			out_len++;

+		}

+		snprintf(out + out_len, word_len + 11, "snapshot=%s", txtbuf);

+	}

 	return 0;

 }

-- 

1.8.3.1