This is a note to let you know that I've just added the patch titled
Btrfs: fix an integer overflow check
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-fix-an-integer-overflow-check.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Dec 21 09:02:40 CET 2017
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date: Fri, 17 Mar 2017 23:51:20 +0300
Subject: Btrfs: fix an integer overflow check
From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
[ Upstream commit 457ae7268b29c33dee1c0feb143a15f6029d177b ]
This isn't super serious because you need CAP_ADMIN to run this code.
I added this integer overflow check last year but apparently I am
rubbish at writing integer overflow checks... There are two issues.
First, access_ok() works on unsigned long type and not u64 so on 32 bit
systems the access_ok() could be checking a truncated size. The other
issue is that we should be using a stricter limit so we don't overflow
the kzalloc() setting ctx->clone_roots later in the function after the
access_ok():
alloc_size = sizeof(struct clone_root) * (arg->clone_sources_count + 1);
sctx->clone_roots = kzalloc(alloc_size, GFP_KERNEL | __GFP_NOWARN);
Fixes: f5ecec3ce21f ("btrfs: send: silence an integer overflow warning")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: David Sterba <dsterba@xxxxxxxx>
[ added comment ]
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/send.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -6196,8 +6196,13 @@ long btrfs_ioctl_send(struct file *mnt_f
goto out;
}
+ /*
+ * Check that we don't overflow at later allocations, we request
+ * clone_sources_count + 1 items, and compare to unsigned long inside
+ * access_ok.
+ */
if (arg->clone_sources_count >
- ULLONG_MAX / sizeof(*arg->clone_sources)) {
+ ULONG_MAX / sizeof(struct clone_root) - 1) {
ret = -EINVAL;
goto out;
}
Patches currently in stable-queue which might be from dan.carpenter@xxxxxxxxxx are
queue-4.9/bna-integer-overflow-bug-in-debugfs.patch
queue-4.9/btrfs-fix-an-integer-overflow-check.patch
queue-4.9/ib-rxe-double-free-on-error.patch