From e7b702b1a8f2a6961367da903217e669be0f099f Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 18 Apr 2010 21:25:11 +0100 Subject: [PATCH 1/4] Inotify: undefined reference to `anon_inode_getfd' Fix: fs/built-in.o: In function `sys_inotify_init1': summary.c:(.text+0x347a4): undefined reference to `anon_inode_getfd' found by kautobuild with arms bcmring_defconfig, which ends up with INOTIFY_USER enabled (through the 'default y') but leaves ANON_INODES unset. However, inotify_user.c uses anon_inode_getfd(). Signed-off-by: Russell King Signed-off-by: Eric Paris --- fs/notify/inotify/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/notify/inotify/Kconfig b/fs/notify/inotify/Kconfig index b3a159b21cfd..4427f8c14239 100644 --- a/fs/notify/inotify/Kconfig +++ b/fs/notify/inotify/Kconfig @@ -17,6 +17,7 @@ config INOTIFY_USER bool "Inotify support for userspace" select ANON_INODES select FSNOTIFY + select ANON_INODES default y ---help--- Say Y here to enable inotify support for userspace, including the From 3dbc6fb6a3c8a7dc164ae330ab024a3fe65ae53e Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 11 May 2010 17:16:23 -0400 Subject: [PATCH 2/4] inotify: clean up the inotify_add_watch out path inotify_add_watch explictly frees the unused inode mark, but it can just use the generic code. Just do that. Signed-off-by: Eric Paris --- fs/notify/inotify/inotify_user.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index 472cdf29ef82..40da732eb73c 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -578,16 +578,13 @@ static int inotify_new_watch(struct fsnotify_group *group, /* return the watch descriptor for this new entry */ ret = tmp_ientry->wd; - /* match the ref from fsnotify_init_markentry() */ - fsnotify_put_mark(&tmp_ientry->fsn_entry); - /* if this mark added a new event update the group mask */ if (mask & ~group->mask) fsnotify_recalc_group_mask(group); out_err: - if (ret < 0) - kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry); + /* match the ref from fsnotify_init_markentry() */ + fsnotify_put_mark(&tmp_ientry->fsn_entry); return ret; } From e08733446e72b983fed850fc5d8bd21b386feb29 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Tue, 11 May 2010 17:17:40 -0400 Subject: [PATCH 3/4] inotify: race use after free/double free in inotify inode marks There is a race in the inotify add/rm watch code. A task can find and remove a mark which doesn't have all of it's references. This can result in a use after free/double free situation. Task A Task B ------------ ----------- inotify_new_watch() allocate a mark (refcnt == 1) add it to the idr inotify_rm_watch() inotify_remove_from_idr() fsnotify_put_mark() refcnt hits 0, free take reference because we are on idr [at this point it is a use after free] [time goes on] refcnt may hit 0 again, double free The fix is to take the reference BEFORE the object can be found in the idr. Signed-off-by: Eric Paris Cc: --- fs/notify/inotify/inotify_user.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index 40da732eb73c..e46ca685b9be 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -546,21 +546,24 @@ static int inotify_new_watch(struct fsnotify_group *group, if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL))) goto out_err; + /* we are putting the mark on the idr, take a reference */ + fsnotify_get_mark(&tmp_ientry->fsn_entry); + spin_lock(&group->inotify_data.idr_lock); ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry, group->inotify_data.last_wd+1, &tmp_ientry->wd); spin_unlock(&group->inotify_data.idr_lock); if (ret) { + /* we didn't get on the idr, drop the idr reference */ + fsnotify_put_mark(&tmp_ientry->fsn_entry); + /* idr was out of memory allocate and try again */ if (ret == -EAGAIN) goto retry; goto out_err; } - /* we put the mark on the idr, take a reference */ - fsnotify_get_mark(&tmp_ientry->fsn_entry); - /* we are on the idr, now get on the inode */ ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode); if (ret) { From b3b38d842fa367d862b83e7670af4e0fd6a80fc0 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Wed, 12 May 2010 15:34:07 -0700 Subject: [PATCH 4/4] inotify: don't leak user struct on inotify release inotify_new_group() receives a get_uid-ed user_struct and saves the reference on group->inotify_data.user. The problem is that free_uid() is never called on it. Issue seem to be introduced by 63c882a0 (inotify: reimplement inotify using fsnotify) after 2.6.30. Signed-off-by: Pavel Emelyanov Eric Paris Cc: Signed-off-by: Andrew Morton Signed-off-by: Eric Paris --- fs/notify/inotify/inotify_fsnotify.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index 1afb0a10229f..e27960cd76ab 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -28,6 +28,7 @@ #include /* struct path */ #include /* kmem_* */ #include +#include #include "inotify.h" @@ -146,6 +147,7 @@ static void inotify_free_group_priv(struct fsnotify_group *group) idr_for_each(&group->inotify_data.idr, idr_callback, group); idr_remove_all(&group->inotify_data.idr); idr_destroy(&group->inotify_data.idr); + free_uid(group->inotify_data.user); } void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv)