Home Home > GIT Browse
summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDavid Miller <davem@davemloft.net>2008-11-06 00:37:40 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2008-11-07 09:55:19 -0800
commit1dbbd0bf5d15397a4e4a1ae3e3e82e0fe4f83c3a (patch)
tree78ed4f68eb606e367797b522e11b21a917f168c1
parentdcc5bc3d9f306cbb5e2f55d65bce1c8372b25fde (diff)
net: Fix recursive descent in __scm_destroy().
commit f8d570a4745835f2238a33b537218a1bb03fc671 and 3b53fbf4314594fa04544b02b2fc6e607912da18 upstream (because once wasn't good enough...) __scm_destroy() walks the list of file descriptors in the scm_fp_list pointed to by the scm_cookie argument. Those, in turn, can close sockets and invoke __scm_destroy() again. There is nothing which limits how deeply this can occur. The idea for how to fix this is from Linus. Basically, we do all of the fput()s at the top level by collecting all of the scm_fp_list objects hit by an fput(). Inside of the initial __scm_destroy() we keep running the list until it is empty. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--include/linux/sched.h4
-rw-r--r--include/net/scm.h5
-rw-r--r--net/core/scm.c24
3 files changed, 27 insertions, 6 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3d9120c5ad15..6bfb8490077c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1286,7 +1286,9 @@ struct task_struct {
atomic_t fs_excl; /* holding fs exclusive resources */
struct rcu_head rcu;
- /*
+ struct list_head *scm_work_list;
+
+/*
* cache last used pipe for splice
*/
struct pipe_inode_info *splice_pipe;
diff --git a/include/net/scm.h b/include/net/scm.h
index 06df126103ca..33e9986beb86 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -14,8 +14,9 @@
struct scm_fp_list
{
- int count;
- struct file *fp[SCM_MAX_FD];
+ struct list_head list;
+ int count;
+ struct file *fp[SCM_MAX_FD];
};
struct scm_cookie
diff --git a/net/core/scm.c b/net/core/scm.c
index 10f5c65f6a47..ab242cc1acca 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -75,6 +75,7 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
if (!fpl)
return -ENOMEM;
*fplp = fpl;
+ INIT_LIST_HEAD(&fpl->list);
fpl->count = 0;
}
fpp = &fpl->fp[fpl->count];
@@ -106,9 +107,25 @@ void __scm_destroy(struct scm_cookie *scm)
if (fpl) {
scm->fp = NULL;
- for (i=fpl->count-1; i>=0; i--)
- fput(fpl->fp[i]);
- kfree(fpl);
+ if (current->scm_work_list) {
+ list_add_tail(&fpl->list, current->scm_work_list);
+ } else {
+ LIST_HEAD(work_list);
+
+ current->scm_work_list = &work_list;
+
+ list_add(&fpl->list, &work_list);
+ while (!list_empty(&work_list)) {
+ fpl = list_first_entry(&work_list, struct scm_fp_list, list);
+
+ list_del(&fpl->list);
+ for (i=fpl->count-1; i>=0; i--)
+ fput(fpl->fp[i]);
+ kfree(fpl);
+ }
+
+ current->scm_work_list = NULL;
+ }
}
}
@@ -284,6 +301,7 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
new_fpl = kmalloc(sizeof(*fpl), GFP_KERNEL);
if (new_fpl) {
+ INIT_LIST_HEAD(&new_fpl->list);
for (i=fpl->count-1; i>=0; i--)
get_file(fpl->fp[i]);
memcpy(new_fpl, fpl, sizeof(*fpl));