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| author | Peng Zhang <zhangpeng.00@bytedance.com> | 2023-04-11 07:10:04 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-26 15:30:03 +0300 |
| commit | e72b3194bbabf6dfae7ae882306f435188365b8f (patch) | |
| tree | bbafaefe3f867a130f707dc13bf2b2cfe142442c | |
| parent | 3bbdd9e29fe83f945870c9e49392a3c80808da8e (diff) | |
| download | linux-e72b3194bbabf6dfae7ae882306f435188365b8f.tar.xz | |
maple_tree: fix a potential memory leak, OOB access, or other unpredictable bug
commit 1f5f12ece722aacea1769fb644f27790ede339dc upstream.
In mas_alloc_nodes(), "node->node_count = 0" means to initialize the
node_count field of the new node, but the node may not be a new node. It
may be a node that existed before and node_count has a value, setting it
to 0 will cause a memory leak. At this time, mas->alloc->total will be
greater than the actual number of nodes in the linked list, which may
cause many other errors. For example, out-of-bounds access in
mas_pop_node(), and mas_pop_node() may return addresses that should not be
used. Fix it by initializing node_count only for new nodes.
Also, by the way, an if-else statement was removed to simplify the code.
Link: https://lkml.kernel.org/r/20230411041005.26205-1-zhangpeng.00@bytedance.com
Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | lib/maple_tree.c | 19 |
1 files changed, 7 insertions, 12 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index a84837962c8b..7091be30862d 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -1298,26 +1298,21 @@ static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp) node = mas->alloc; node->request_count = 0; while (requested) { - max_req = MAPLE_ALLOC_SLOTS; - if (node->node_count) { - unsigned int offset = node->node_count; - - slots = (void **)&node->slot[offset]; - max_req -= offset; - } else { - slots = (void **)&node->slot; - } - + max_req = MAPLE_ALLOC_SLOTS - node->node_count; + slots = (void **)&node->slot[node->node_count]; max_req = min(requested, max_req); count = mt_alloc_bulk(gfp, max_req, slots); if (!count) goto nomem_bulk; + if (node->node_count == 0) { + node->slot[0]->node_count = 0; + node->slot[0]->request_count = 0; + } + node->node_count += count; allocated += count; node = node->slot[0]; - node->node_count = 0; - node->request_count = 0; requested -= count; } mas->alloc->total = allocated; |