5.4-stable patches

added patches:
	binder-fix-use-after-free-in-shinker-s-callback.patch

diff --git a/queue-5.4/binder-fix-use-after-free-in-shinker-s-callback.patch b/queue-5.4/binder-fix-use-after-free-in-shinker-s-callback.patch
new file mode 100644 (file)
index 0000000..c69dc73
--- /dev/null
+++ b/queue-5.4/binder-fix-use-after-free-in-shinker-s-callback.patch
@@ -0,0 +1,107 @@
+From 3f489c2067c5824528212b0fc18b28d51332d906 Mon Sep 17 00:00:00 2001
+From: Carlos Llamas <cmllamas@google.com>
+Date: Fri, 1 Dec 2023 17:21:31 +0000
+Subject: binder: fix use-after-free in shinker's callback
+
+From: Carlos Llamas <cmllamas@google.com>
+
+commit 3f489c2067c5824528212b0fc18b28d51332d906 upstream.
+
+The mmap read lock is used during the shrinker's callback, which means
+that using alloc->vma pointer isn't safe as it can race with munmap().
+As of commit dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in
+munmap") the mmap lock is downgraded after the vma has been isolated.
+
+I was able to reproduce this issue by manually adding some delays and
+triggering page reclaiming through the shrinker's debug sysfs. The
+following KASAN report confirms the UAF:
+
+  ==================================================================
+  BUG: KASAN: slab-use-after-free in zap_page_range_single+0x470/0x4b8
+  Read of size 8 at addr ffff356ed50e50f0 by task bash/478
+
+  CPU: 1 PID: 478 Comm: bash Not tainted 6.6.0-rc5-00055-g1c8b86a3799f-dirty #70
+  Hardware name: linux,dummy-virt (DT)
+  Call trace:
+   zap_page_range_single+0x470/0x4b8
+   binder_alloc_free_page+0x608/0xadc
+   __list_lru_walk_one+0x130/0x3b0
+   list_lru_walk_node+0xc4/0x22c
+   binder_shrink_scan+0x108/0x1dc
+   shrinker_debugfs_scan_write+0x2b4/0x500
+   full_proxy_write+0xd4/0x140
+   vfs_write+0x1ac/0x758
+   ksys_write+0xf0/0x1dc
+   __arm64_sys_write+0x6c/0x9c
+
+  Allocated by task 492:
+   kmem_cache_alloc+0x130/0x368
+   vm_area_alloc+0x2c/0x190
+   mmap_region+0x258/0x18bc
+   do_mmap+0x694/0xa60
+   vm_mmap_pgoff+0x170/0x29c
+   ksys_mmap_pgoff+0x290/0x3a0
+   __arm64_sys_mmap+0xcc/0x144
+
+  Freed by task 491:
+   kmem_cache_free+0x17c/0x3c8
+   vm_area_free_rcu_cb+0x74/0x98
+   rcu_core+0xa38/0x26d4
+   rcu_core_si+0x10/0x1c
+   __do_softirq+0x2fc/0xd24
+
+  Last potentially related work creation:
+   __call_rcu_common.constprop.0+0x6c/0xba0
+   call_rcu+0x10/0x1c
+   vm_area_free+0x18/0x24
+   remove_vma+0xe4/0x118
+   do_vmi_align_munmap.isra.0+0x718/0xb5c
+   do_vmi_munmap+0xdc/0x1fc
+   __vm_munmap+0x10c/0x278
+   __arm64_sys_munmap+0x58/0x7c
+
+Fix this issue by performing instead a vma_lookup() which will fail to
+find the vma that was isolated before the mmap lock downgrade. Note that
+this option has better performance than upgrading to a mmap write lock
+which would increase contention. Plus, mmap_write_trylock() has been
+recently removed anyway.
+
+Fixes: dd2283f2605e ("mm: mmap: zap pages with read mmap_sem in munmap")
+Cc: stable@vger.kernel.org
+Cc: Liam Howlett <liam.howlett@oracle.com>
+Cc: Minchan Kim <minchan@kernel.org>
+Reviewed-by: Alice Ryhl <aliceryhl@google.com>
+Signed-off-by: Carlos Llamas <cmllamas@google.com>
+Link: https://lore.kernel.org/r/20231201172212.1813387-3-cmllamas@google.com
+[cmllamas: use find_vma() instead of vma_lookup() as commit ce6d42f2e4a2
+ is missing in v5.4. This only works because we check the vma against
+ our cached alloc->vma pointer. Also, unlock via up_read() instead of
+ mmap_read_unlock() as commit d8ed45c5dcd4 is also missing in v5.4.]
+Signed-off-by: Carlos Llamas <cmllamas@google.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/android/binder_alloc.c |    6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+--- a/drivers/android/binder_alloc.c
++++ b/drivers/android/binder_alloc.c
+@@ -954,7 +954,9 @@ enum lru_status binder_alloc_free_page(s
+               goto err_mmget;
+       if (!down_read_trylock(&mm->mmap_sem))
+               goto err_down_read_mmap_sem_failed;
+-      vma = binder_alloc_get_vma(alloc);
++      vma = find_vma(mm, page_addr);
++      if (vma && vma != binder_alloc_get_vma(alloc))
++              goto err_invalid_vma;
+ 
+       list_lru_isolate(lru, item);
+       spin_unlock(lock);
+@@ -980,6 +982,8 @@ enum lru_status binder_alloc_free_page(s
+       mutex_unlock(&alloc->mutex);
+       return LRU_REMOVED_RETRY;
+ 
++err_invalid_vma:
++      up_read(&mm->mmap_sem);
+ err_down_read_mmap_sem_failed:
+       mmput_async(mm);
+ err_mmget:

diff --git a/queue-5.4/series b/queue-5.4/series
index 2c16f97325c99013605b99281e027152ab10a85e..dccab965f16e32bd13917af1ec3bdaf8839172fe 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -137,3 +137,4 @@ mmc-sdhci_omap-fix-ti-soc-dependencies.patch
 of-fix-double-free-in-of_parse_phandle_with_args_map.patch
 of-unittest-fix-of_count_phandle_with_args-expected-.patch
 binder-fix-async-space-check-for-0-sized-buffers.patch
+binder-fix-use-after-free-in-shinker-s-callback.patch