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authorEric Paris <eparis@redhat.com>2010-10-28 17:21:57 -0400
committerEric Paris <eparis@redhat.com>2010-10-28 17:22:14 -0400
commite7099d8a5a34d2876908a9fab4952dabdcfc5909 (patch)
tree34f62d8ae23c4c115a0b615cd13e9ae7ddd28b42 /fs/notify/fanotify/fanotify_user.c
parent5dd03f55fd2f21916ce248bb2e68bbfb39d94fe5 (diff)
fanotify: limit the number of marks in a single fanotify group
There is currently no limit on the number of marks a given fanotify group can have. Since fanotify is gated on CAP_SYS_ADMIN this was not seen as a serious DoS threat. This patch implements a default of 8192, the same as inotify to work towards removing the CAP_SYS_ADMIN gating and eliminating the default DoS'able status. Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'fs/notify/fanotify/fanotify_user.c')
-rw-r--r--fs/notify/fanotify/fanotify_user.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 43d66d9b2ef..1d33d7db277 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -17,6 +17,7 @@
#include <asm/ioctls.h>
#define FANOTIFY_DEFAULT_MAX_EVENTS 16384
+#define FANOTIFY_DEFAULT_MAX_MARKS 8192
extern const struct fsnotify_ops fanotify_fsnotify_ops;
@@ -584,6 +585,9 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
if (!fsn_mark) {
int ret;
+ if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
+ return -ENOSPC;
+
fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
if (!fsn_mark)
return -ENOMEM;
@@ -626,6 +630,9 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
if (!fsn_mark) {
int ret;
+ if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
+ return -ENOSPC;
+
fsn_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
if (!fsn_mark)
return -ENOMEM;
@@ -700,6 +707,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
group->max_events = FANOTIFY_DEFAULT_MAX_EVENTS;
}
+ group->fanotify_data.max_marks = FANOTIFY_DEFAULT_MAX_MARKS;
+
fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
if (fd < 0)
goto out_put_group;