From: "Liam R. Howlett" <Liam.Howlett@oracle.com> stable inclusion from stable-v6.6.99 commit e63032e66bca1d06e600033f3369ba3db3af0870 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICOXDR CVE: CVE-2025-38364 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit fba46a5d83ca8decb338722fb4899026d8d9ead2 upstream. Temporarily clear the preallocation flag when explicitly requesting allocations. Pre-existing allocations are already counted against the request through mas_node_count_gfp(), but the allocations will not happen if the MA_STATE_PREALLOC flag is set. This flag is meant to avoid re-allocating in bulk allocation mode, and to detect issues with preallocation calculations. The MA_STATE_PREALLOC flag should also always be set on zero allocations so that detection of underflow allocations will print a WARN_ON() during consumption. User visible effect of this flaw is a WARN_ON() followed by a null pointer dereference when subsequent requests for larger number of nodes is ignored, such as the vma merge retry in mmap_region() caused by drivers altering the vma flags (which happens in v6.6, at least) Link: https://lkml.kernel.org/r/20250616184521.3382795-3-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com> Reported-by: Hailong Liu <hailong.liu@oppo.com> Link: https://lore.kernel.org/all/1652f7eb-a51b-4fee-8058-c73af63bacd1@oppo.com/ Link: https://lore.kernel.org/all/20250428184058.1416274-1-Liam.Howlett@oracle.com... Link: https://lore.kernel.org/all/20250429014754.1479118-1-Liam.Howlett@oracle.com... Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Hailong Liu <hailong.liu@oppo.com> Cc: zhangpeng.00@bytedance.com <zhangpeng.00@bytedance.com> Cc: Steve Kang <Steve.Kang@unisoc.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: lib/maple_tree.c [context conflicts due to merged mainline 5143eecd2af2 ("lib/maple_tree.c: fix build error due to hotfix alteration")] Signed-off-by: Ze Zuo <zuoze1@huawei.com> --- lib/maple_tree.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 88e478d6840c..cdec348e7820 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5571,7 +5571,7 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) /* At this point, we are at the leaf node that needs to be altered. */ /* Exact fit, no nodes needed. */ if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last) - return 0; + goto set_flag; mas_wr_end_piv(&wr_mas); node_size = mas_wr_new_end(&wr_mas); @@ -5580,10 +5580,10 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) if (node_size == mas->end) { /* reuse node */ if (!mt_in_rcu(mas->tree)) - return 0; + goto set_flag; /* shifting boundary */ if (wr_mas.offset_end - mas->offset == 1) - return 0; + goto set_flag; } if (node_size >= mt_slots[wr_mas.type]) { @@ -5602,10 +5602,13 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) /* node store, slot store needs one node */ ask_now: + mas->mas_flags &= ~MA_STATE_PREALLOC; mas_node_count_gfp(mas, request, gfp); - mas->mas_flags |= MA_STATE_PREALLOC; - if (likely(!mas_is_err(mas))) + if (likely(!mas_is_err(mas))) { +set_flag: + mas->mas_flags |= MA_STATE_PREALLOC; return 0; + } mas_set_alloc_req(mas, 0); ret = xa_err(mas->node); -- 2.25.1