[PATCH] SELinux: support mls categories for context mounts (3528a953) · Commits · 戴 / test

Allows commas to be embedded into context mount options (i.e. "-o context=some_selinux_context_t"), to better support multiple categories, which are separated by commas and confuse mount. For example, with the current code: mount -t iso9660 /dev/cdrom /media/cdrom -o \ ro,context=system_u:object_r:iso9660_t:s0:c1,c3,c4,exec The context option that will be interpreted by SELinux is context=system_u:object_r:iso9660_t:s0:c1 instead of context=system_u:object_r:iso9660_t:s0:c1,c3,c4 The options that will be passed on to the file system will be ro,c3,c4,exec. The proposed solution is to allow/require the SELinux context option specified to mount to use quotes when the context contains a comma. This patch modifies the option parsing in parse_opts(), contained in mount.c, to take options after finding a comma only if it hasn't seen a quote or if the quotes are matched. It also introduces a new function that will strip the quotes from the context option prior to translation. The quotes are replaced after the translation is completed to insure that in the event the raw context contains commas the kernel will be able to interpret the correct context. Signed-off-by:

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

James Morris <jmorris@namei.org> Acked-by:

Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

security/selinux/hooks.c

+30 −5

Original line number	Diff line number	Diff line
		@@ -398,7 +398,7 @@ static int try_context_mount(struct super_block sb, void data)
		/* Standard string-based options. */
		char p, options = data;

		while ((p = strsep(&options, ",")) != NULL) {
		while ((p = strsep(&options, "\|")) != NULL) {
		int token;
		substring_t args[MAX_OPT_ARGS];

		@@ -1923,18 +1923,40 @@ static inline void take_option(char *to, char from, int *first, int len)
		if (!*first) {
		**to = ',';
		*to += 1;
		}
		else
		} else
		*first = 0;
		memcpy(*to, from, len);
		*to += len;
		}

		static inline void take_selinux_option(char *to, char from, int *first,
		int len)
		{
		int current_size = 0;

		if (!*first) {
		**to = '\|';
		*to += 1;
		}
		else
		*first = 0;

		while (current_size < len) {
		if (*from != '"') {
		*to = from;
		*to += 1;
		}
		from += 1;
		current_size += 1;
		}
		}

		static int selinux_sb_copy_data(struct file_system_type type, void orig, void *copy)
		{
		int fnosec, fsec, rc = 0;
		char in_save, in_curr, *in_end;
		char sec_curr, nosec_save, *nosec;
		int open_quote = 0;

		in_curr = orig;
		sec_curr = copy;
		@@ -1956,11 +1978,14 @@ static int selinux_sb_copy_data(struct file_system_type type, void orig, void
		in_save = in_end = orig;

		do {
		if (in_end == ',' \|\| in_end == '\0') {
		if (*in_end == '"')
		open_quote = !open_quote;
		if ((*in_end == ',' && open_quote == 0) \|\|
		*in_end == '\0') {
		int len = in_end - in_curr;

		if (selinux_option(in_curr, len))
		take_option(&sec_curr, in_curr, &fsec, len);
		take_selinux_option(&sec_curr, in_curr, &fsec, len);
		else
		take_option(&nosec, in_curr, &fnosec, len);

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