Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 66081a72 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Greg Kroah-Hartman
Browse files

sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat() 



The warning check for duplicate sysfs entries can cause a buffer overflow
when printing the warning, as strcat() doesn't check buffer sizes.
Use strlcat() instead.

Since strlcat() doesn't return a pointer to the passed buffer, unlike
strcat(), I had to convert the nested concatenation in sysfs_add_one() to
an admittedly more obscure comma operator construct, to avoid emitting code
for the concatenation if CONFIG_BUG is disabled.

Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c0d2af63

fs/sysfs/dir.c

+8 −8
Original line number Diff line number Diff line
@@ -485,20 +485,18 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) 
/**

 *	sysfs_pathname - return full path to sysfs dirent

 *	@sd: sysfs_dirent whose path we want

 *	@path: caller allocated buffer

 *	@path: caller allocated buffer of size PATH_MAX

 *

 *	Gives the name "/" to the sysfs_root entry; any path returned

 *	is relative to wherever sysfs is mounted.

 *

 *	XXX: does no error checking on @path size

 */

static char *sysfs_pathname(struct sysfs_dirent *sd, char *path)

{

	if (sd->s_parent) {

		sysfs_pathname(sd->s_parent, path);

		strcat(path, "/");

		strlcat(path, "/", PATH_MAX);

	}

	strcat(path, sd->s_name);

	strlcat(path, sd->s_name, PATH_MAX);

	return path;

}
@@ -531,9 +529,11 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) 
		char *path = kzalloc(PATH_MAX, GFP_KERNEL);

		WARN(1, KERN_WARNING

		     "sysfs: cannot create duplicate filename '%s'\n",

		     (path == NULL) ? sd->s_name :

		     strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"),

		            sd->s_name));

		     (path == NULL) ? sd->s_name

				    : (sysfs_pathname(acxt->parent_sd, path),

				       strlcat(path, "/", PATH_MAX),

				       strlcat(path, sd->s_name, PATH_MAX),

				       path));

		kfree(path);

	}