[Patch 3/3] nfsmount: quote context mount option to avoid comma collision

[Patch 3/3] nfsmount: quote context mount option to avoid comma collision

[Cory Olmo]

To avoid the collision between commas in security contexts and the 
delimiter betweeen mount options this patch introduces support for 
quoting the context option.

It modifies the option parsing in parse_opts(), contained in mount.c, 
and parse_options(), in nfsmount.c, to process an option after finding 
a comma only if it hasn't seen a quote or if the quotes are matched.

Signed-off-by: Cory Olmo <colmo@TrustedCS.com>
---

 mount.c    |   19 +++++++++++++++++--
 nfsmount.c |   33 ++++++++++++++++++++++++++++++---
 2 files changed, 47 insertions(+), 5 deletions(-)


diff --git a/utils/mount/mount.c b/utils/mount/mount.c
index cb646d6..6c6de9b 100644
--- a/utils/mount/mount.c
+++ b/utils/mount/mount.c
@@ -277,12 +277,27 @@ static void parse_opts (const char *opti
 		char *opts = xstrdup(options);
 		char *opt;
 		int len = strlen(opts) + 20;
+		int open_quote = 0;
+		char *opt_start = NULL;
+		char *opt_end = NULL;
 
 		*extra_opts = xmalloc(len);
 		**extra_opts = '\0';
 
-		for (opt = strtok(opts, ","); opt; opt = strtok(NULL, ","))
-			parse_opt(opt, flags, *extra_opts, len);
+		opt_start = opt_end = opts;
+		do {
+			if (*opt_end == '"') {
+				open_quote = !open_quote;
+			}
+			if ((*opt_end == ',' && open_quote == 0) ||
+					*opt_end == '\0') {
+				opt = xstrndup(opt_start, opt_end - opt_start);
+				parse_opt(opt, flags, *extra_opts, len);
+				opt_start = opt_end + 1;
+				free(opt);
+				opt = NULL;
+			}
+		} while (*opt_end++);
 
 		free(opts);
 	}
diff --git a/utils/mount/nfsmount.c b/utils/mount/nfsmount.c
index cef13d3..3c55835 100644
--- a/utils/mount/nfsmount.c
+++ b/utils/mount/nfsmount.c
@@ -551,12 +551,27 @@ parse_options(char *old_opts, struct nfs
 	char *opt, *opteq;
 	char *mounthost = NULL;
 	char cbuf[128];
+	char *opt_start, *opt_end;
+	int open_quote = 0;
 
 	data->flags = 0;
 	*bg = 0;
 
 	len = strlen(new_opts);
-	for (opt = strtok(old_opts, ","); opt; opt = strtok(NULL, ",")) {
+	opt_start = opt_end = old_opts;
+	do {
+		if (*opt_end == '"') {
+			open_quote = !open_quote;
+		}
+		if (!((*opt_end == ',' && open_quote == 0) ||
+				*opt_end == '\0')) {
+			continue;
+		}
+		opt = xstrndup(opt_start, opt_end - opt_start);
+		opt_start = opt_end + 1;
+		if (*opt == '\0')
+			continue;
+
 		if (strlen(opt) >= sizeof(cbuf))
 			goto bad_parameter;
 		if ((opteq = strchr(opt, '=')) && isdigit(opteq[1])) {
@@ -677,7 +692,16 @@ #endif
  						 NFS_MAX_CONTEXT_LEN);
 					goto bad_parameter;
  				}
- 				strncpy(data->context, context, NFS_MAX_CONTEXT_LEN);
+				/* The context string is in the format of
+				 * "system_u:object_r:...".  We only want
+				 * the context str between the quotes.
+				 */
+				if (*context == '"')
+					strncpy(data->context, context+1, 
+							strlen(context)-2);
+				else
+					strncpy(data->context, context, 
+							NFS_MAX_CONTEXT_LEN);
  			} else if (!sloppy)
 				goto bad_parameter;
 			sprintf(cbuf, "%s=%s,", opt, opteq+1);
@@ -783,7 +807,10 @@ #endif
 			goto out_bad;
 		}
 		strcat(new_opts, cbuf);
-	}
+		free(opt);
+		opt = NULL;
+	} while (*opt_end++);
+
 	/* See if the nfs host = mount host. */
 	if (mounthost) {
 		if (!nfs_gethostbyname(mounthost, mnt_saddr))

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