It is possible for unaware callers of several idr functions to accidentally underflow the index by specifying a id that is less than the idr base.
Signed-off-by: Jordan Crouse <[email protected]> --- lib/idr.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/lib/idr.c b/lib/idr.c index 66a3748..d9e180c 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -151,6 +151,9 @@ EXPORT_SYMBOL(idr_alloc_cyclic); */ void *idr_remove(struct idr *idr, unsigned long id) { + if (id < idr->idr_base) + return NULL; + return radix_tree_delete_item(&idr->idr_rt, id - idr->idr_base, NULL); } EXPORT_SYMBOL_GPL(idr_remove); @@ -171,6 +174,9 @@ EXPORT_SYMBOL_GPL(idr_remove); */ void *idr_find(const struct idr *idr, unsigned long id) { + if (id < idr->idr_base) + return NULL; + return radix_tree_lookup(&idr->idr_rt, id - idr->idr_base); } EXPORT_SYMBOL_GPL(idr_find); @@ -302,6 +308,9 @@ void *idr_replace(struct idr *idr, void *ptr, unsigned long id) void __rcu **slot = NULL; void *entry; + if (id < idr->idr_base) + return ERR_PTR(-ENOENT); + id -= idr->idr_base; entry = __radix_tree_lookup(&idr->idr_rt, id, &node, &slot); -- 2.7.4
