From: Alessandro Astone ales.astone@gmail.com
stable inclusion from stable-v5.10.157 commit 017de842533f4334d646f1d480f591f4ca9f5c7a category: bugfix bugzilla: 188431, https://gitee.com/src-openeuler/kernel/issues/I6DKVG CVE: CVE-2023-20938
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 2d1746e3fda0c3612143d7c06f8e1d1830c13e23 upstream.
When handling BINDER_TYPE_FDA object we are pushing a parent fixup with a certain skip_size but no scatter-gather copy object, since the copy is handled standalone. If BINDER_TYPE_FDA is the last children the scatter-gather copy loop will never stop to skip it, thus we are left with an item in the parent fixup list. This will trigger the BUG_ON().
This is reproducible in android when playing a video. We receive a transaction that looks like this: obj[0] BINDER_TYPE_PTR, parent obj[1] BINDER_TYPE_PTR, child obj[2] BINDER_TYPE_PTR, child obj[3] BINDER_TYPE_FDA, child
Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data") Acked-by: Todd Kjos tkjos@google.com Cc: stable stable@kernel.org Signed-off-by: Alessandro Astone ales.astone@gmail.com Link: https://lore.kernel.org/r/20220415120015.52684-2-ales.astone@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Carlos Llamas cmllamas@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Li Huafei lihuafei1@huawei.com Reviewed-by: Zheng Yejian zhengyejian1@huawei.com Reviewed-by: Wang Weiyang wangweiyang2@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- drivers/android/binder.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index ef76905a7f46..512cf08e2c07 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2726,6 +2726,7 @@ static int binder_do_deferred_txn_copies(struct binder_alloc *alloc, { int ret = 0; struct binder_sg_copy *sgc, *tmpsgc; + struct binder_ptr_fixup *tmppf; struct binder_ptr_fixup *pf = list_first_entry_or_null(pf_head, struct binder_ptr_fixup, node); @@ -2780,7 +2781,11 @@ static int binder_do_deferred_txn_copies(struct binder_alloc *alloc, list_del(&sgc->node); kfree(sgc); } - BUG_ON(!list_empty(pf_head)); + list_for_each_entry_safe(pf, tmppf, pf_head, node) { + BUG_ON(pf->skip_size == 0); + list_del(&pf->node); + kfree(pf); + } BUG_ON(!list_empty(sgc_head));
return ret > 0 ? -EINVAL : ret;