Commit c34706ac authored by Amir Goldstein's avatar Amir Goldstein
Browse files

ovl: fix regression in parsing of mount options with escaped comma 



Ever since commit 91c77947 ("ovl: allow filenames with comma"), the
following example was legit overlayfs mount options:

  mount -t overlay overlay -o 'lowerdir=/tmp/a\,b/lower' /mnt

The conversion to new mount api moved to using the common helper
generic_parse_monolithic() and discarded the specialized ovl_next_opt()
option separator.

Bring back ovl_next_opt() and use vfs_parse_monolithic_sep() to fix the
regression.

Reported-by: default avatarRyan Hendrickson <ryan.hendrickson@alum.mit.edu>
Closes: https://lore.kernel.org/r/8da307fb-9318-cf78-8a27-ba5c5a0aef6d@alum.mit.edu/


Fixes: 1784fbc2 ("ovl: port to new mount api")
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
parent e001d144

fs/overlayfs/params.c

+29 −0
Original line number Diff line number Diff line
@@ -157,6 +157,34 @@ const struct fs_parameter_spec ovl_parameter_spec[] = { 
	{}

};



static char *ovl_next_opt(char **s)

{

	char *sbegin = *s;

	char *p;



	if (sbegin == NULL)

		return NULL;



	for (p = sbegin; *p; p++) {

		if (*p == '\\') {

			p++;

			if (!*p)

				break;

		} else if (*p == ',') {

			*p = '\0';

			*s = p + 1;

			return sbegin;

		}

	}

	*s = NULL;

	return sbegin;

}



static int ovl_parse_monolithic(struct fs_context *fc, void *data)

{

	return vfs_parse_monolithic_sep(fc, data, ovl_next_opt);

}



static ssize_t ovl_parse_param_split_lowerdirs(char *str)

{

	ssize_t nr_layers = 1, nr_colons = 0;
@@ -682,6 +710,7 @@ static int ovl_reconfigure(struct fs_context *fc) 
}



static const struct fs_context_operations ovl_context_ops = {

	.parse_monolithic = ovl_parse_monolithic,

	.parse_param = ovl_parse_param,

	.get_tree    = ovl_get_tree,

	.reconfigure = ovl_reconfigure,