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-rw-r--r--fs/namespace.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 8e3603558e59..ade356c7f14a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -5375,6 +5375,7 @@ SYSCALL_DEFINE4(listmount, const struct mnt_id_req __user *, req,
const size_t maxcount = 1000000;
struct mnt_namespace *ns __free(mnt_ns_release) = NULL;
struct mnt_id_req kreq;
+ u64 last_mnt_id;
ssize_t ret;
if (flags & ~LISTMOUNT_REVERSE)
@@ -5395,6 +5396,11 @@ SYSCALL_DEFINE4(listmount, const struct mnt_id_req __user *, req,
if (ret)
return ret;
+ last_mnt_id = kreq.param;
+ /* The first valid unique mount id is MNT_UNIQUE_ID_OFFSET + 1. */
+ if (last_mnt_id != 0 && last_mnt_id <= MNT_UNIQUE_ID_OFFSET)
+ return -EINVAL;
+
kmnt_ids = kvmalloc_array(nr_mnt_ids, sizeof(*kmnt_ids),
GFP_KERNEL_ACCOUNT);
if (!kmnt_ids)
@@ -5409,7 +5415,7 @@ SYSCALL_DEFINE4(listmount, const struct mnt_id_req __user *, req,
return -ENOENT;
scoped_guard(rwsem_read, &namespace_sem)
- ret = do_listmount(ns, kreq.mnt_id, kreq.param, kmnt_ids,
+ ret = do_listmount(ns, kreq.mnt_id, last_mnt_id, kmnt_ids,
nr_mnt_ids, (flags & LISTMOUNT_REVERSE));
if (ret <= 0)
return ret;