From 903e21e2eea036f6947f523f732e28b33a63ed0f Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 12 Oct 2011 22:02:43 +0000 Subject: [PATCH] sysfs: Reject with a warning invalid uses of tagged directories. sysfs is a core piece of ifrastructure that many people use and few people have all of the rules in their head on how to use it correctly. Add warnings for people using tagged directories improperly to that any misuses can be caught and diagnosed quickly. A single inexpensive test in sysfs_find_dirent is almost sufficient to catch all possible misuses. An additional warning is needed in sysfs_add_dirent so that we actually fail when attempting to add an untagged dirent in a tagged directory. Signed-off-by: Eric W. Biederman Acked-by: Greg Kroah-Hartman Signed-off-by: David S. Miller --- fs/sysfs/dir.c | 14 ++++++++++++++ fs/sysfs/file.c | 3 --- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 352d26d98c0..26f370a9b5c 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -384,6 +384,13 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) { struct sysfs_inode_attrs *ps_iattr; + if (!!sysfs_ns_type(acxt->parent_sd) != !!sd->s_ns) { + WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", + sysfs_ns_type(acxt->parent_sd)? "required": "invalid", + acxt->parent_sd->s_name, sd->s_name); + return -EINVAL; + } + if (sysfs_find_dirent(acxt->parent_sd, sd->s_ns, sd->s_name)) return -EEXIST; @@ -542,6 +549,13 @@ struct sysfs_dirent *sysfs_find_dirent(struct sysfs_dirent *parent_sd, { struct sysfs_dirent *sd; + if (!!sysfs_ns_type(parent_sd) != !!ns) { + WARN(1, KERN_WARNING "sysfs: ns %s in '%s' for '%s'\n", + sysfs_ns_type(parent_sd)? "required": "invalid", + parent_sd->s_name, name); + return NULL; + } + for (sd = parent_sd->s_dir.children; sd; sd = sd->s_sibling) { if (sd->s_ns != ns) continue; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 07c1b4ec00d..d4e6080b4b2 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -466,9 +466,6 @@ void sysfs_notify(struct kobject *k, const char *dir, const char *attr) mutex_lock(&sysfs_mutex); if (sd && dir) - /* Only directories are tagged, so no need to pass - * a tag explicitly. - */ sd = sysfs_find_dirent(sd, NULL, dir); if (sd && attr) sd = sysfs_find_dirent(sd, NULL, attr); -- 2.11.4.GIT