From aa7f1827953100cdde0795289a80c6c077bfe437 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Fri, 12 Feb 2021 20:11:25 -0500 Subject: [PATCH] lib/generic-radix-tree.c: Don't overflow in peek() [ Upstream commit 9492261ff2460252cf2d8de89cdf854c7e2b28a0 ] 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 Signed-off-by: Sasha Levin --- include/linux/generic-radix-tree.h | 7 +++++++ lib/generic-radix-tree.c | 17 ++++++++++++++--- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/include/linux/generic-radix-tree.h b/include/linux/generic-radix-tree.h index 107613f..f6cd0f9 100644 --- a/include/linux/generic-radix-tree.h +++ b/include/linux/generic-radix-tree.h @@ -38,6 +38,7 @@ #include #include +#include #include #include #include @@ -184,6 +185,12 @@ 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 f25eb11..7dfa882 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) -- 2.7.4