diff options
| author | Kent Overstreet <kent.overstreet@gmail.com> | 2021-02-12 20:11:25 -0500 |
|---|---|---|
| committer | Kent Overstreet <kent.overstreet@linux.dev> | 2023-03-13 11:32:13 -0400 |
| commit | feb3ecc208b72e53a9ff674bbba7aee5191917cd (patch) | |
| tree | 9b4b8dc5b857df953fc7b03bc8da9fbfc152b34d | |
| parent | 55f24f62165bb35a2b84b409da8a6028015f0e3b (diff) | |
lib/generic-radix-tree.c: Don't overflow in peek()
When we started spreading new inode numbers throughout most of the 64
bit inode space, that triggered some corner case bugs, in particular
some integer overflows related to the radix tree code. Oops.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
| -rw-r--r-- | include/linux/generic-radix-tree.h | 6 | ||||
| -rw-r--r-- | lib/generic-radix-tree.c | 17 |
2 files changed, 20 insertions, 3 deletions
diff --git a/include/linux/generic-radix-tree.h b/include/linux/generic-radix-tree.h index 107613f7d792..63080822dc84 100644 --- a/include/linux/generic-radix-tree.h +++ b/include/linux/generic-radix-tree.h @@ -184,6 +184,12 @@ void *__genradix_iter_peek(struct genradix_iter *, struct __genradix *, size_t); static inline void __genradix_iter_advance(struct genradix_iter *iter, size_t obj_size) { + if (iter->offset + obj_size < iter->offset) { + iter->offset = SIZE_MAX; + iter->pos = SIZE_MAX; + return; + } + iter->offset += obj_size; if (!is_power_of_2(obj_size) && diff --git a/lib/generic-radix-tree.c b/lib/generic-radix-tree.c index f25eb111c051..7dfa88282b00 100644 --- a/lib/generic-radix-tree.c +++ b/lib/generic-radix-tree.c @@ -166,6 +166,10 @@ void *__genradix_iter_peek(struct genradix_iter *iter, struct genradix_root *r; struct genradix_node *n; unsigned level, i; + + if (iter->offset == SIZE_MAX) + return NULL; + restart: r = READ_ONCE(radix->root); if (!r) @@ -184,10 +188,17 @@ restart: (GENRADIX_ARY - 1); while (!n->children[i]) { + size_t objs_per_ptr = genradix_depth_size(level); + + if (iter->offset + objs_per_ptr < iter->offset) { + iter->offset = SIZE_MAX; + iter->pos = SIZE_MAX; + return NULL; + } + i++; - iter->offset = round_down(iter->offset + - genradix_depth_size(level), - genradix_depth_size(level)); + iter->offset = round_down(iter->offset + objs_per_ptr, + objs_per_ptr); iter->pos = (iter->offset >> PAGE_SHIFT) * objs_per_page; if (i == GENRADIX_ARY) |