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From: David Howells <dhowells@redhat.com>
To: Eric Biggers <ebiggers@google.com>
Cc: dhowells@redhat.com,
	Ben Hutchings <ben.hutchings@codethink.co.uk>,
	stable@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4.4 11/41] KEYS: fix writing past end of user-supplied buffer in keyring_read()
Date: Thu, 19 Oct 2017 16:27:23 +0100	[thread overview]
Message-ID: <10708.1508426843@warthog.procyon.org.uk> (raw)
In-Reply-To: <20171016181206.GC121701@google.com>

Eric Biggers <ebiggers@google.com> wrote:

> Hi Ben, thanks for pointing this out.  I had assumed the "obvious" semantics,
> but it turns out that's not what's documented.

The manpage is correct.  keyctl_read_alloc() in libkeyutils relies on the
behaviour documented there with respect to the full size of the data always
being returned, even if the buffer was too small.

The keyring cannot be modified whilst it is being read, so that's not a
concern.

keyctl_read_alloc() doesn't care if the buffer actually gets written to or
not, but it's best to honour the manpage.

David

  parent reply	other threads:[~2017-10-19 15:27 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-03 12:21 [PATCH 4.4 00/41] 4.4.90-stable review Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 01/41] cifs: release auth_key.response for reconnect Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 02/41] mac80211: flush hw_roc_start work before cancelling the ROC Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 03/41] KVM: PPC: Book3S: Fix race and leak in kvm_vm_ioctl_create_spapr_tce() Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 04/41] tracing: Fix trace_pipe behavior for instance traces Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 05/41] tracing: Erase irqsoff trace with empty write Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 06/41] md/raid5: fix a race condition in stripe batch Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 07/41] md/raid5: preserve STRIPE_ON_UNPLUG_LIST in break_stripe_batch_list Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 08/41] scsi: scsi_transport_iscsi: fix the issue that iscsi_if_rx doesnt parse nlmsg properly Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 09/41] crypto: talitos - Dont provide setkey for non hmac hashing algs Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 10/41] crypto: talitos - fix sha224 Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 11/41] KEYS: fix writing past end of user-supplied buffer in keyring_read() Greg Kroah-Hartman
2017-10-16 15:47   ` Ben Hutchings
2017-10-16 18:12     ` Eric Biggers
2017-10-16 18:12       ` Eric Biggers
2017-10-19 15:27     ` David Howells [this message]
2017-10-19 17:09       ` Eric Biggers
2017-10-24 23:19       ` Eric Biggers
2017-10-25  9:31         ` Ben Hutchings
2017-11-01 15:24         ` David Howells
2017-10-03 12:21 ` [PATCH 4.4 12/41] KEYS: prevent creating a different users keyrings Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 13/41] KEYS: prevent KEYCTL_READ on negative key Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 14/41] powerpc/pseries: Fix parent_dn reference leak in add_dt_node() Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 15/41] Fix SMB3.1.1 guest authentication to Samba Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 16/41] SMB: Validate negotiate (to protect against downgrade) even if signing off Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 17/41] SMB3: Dont ignore O_SYNC/O_DSYNC and O_DIRECT flags Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 18/41] vfs: Return -ENXIO for negative SEEK_HOLE / SEEK_DATA offsets Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 19/41] nl80211: check for the required netlink attributes presence Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 20/41] bsg-lib: dont free job in bsg_prepare_job Greg Kroah-Hartman
2017-10-16 16:32   ` Ben Hutchings
2017-10-03 12:21 ` [PATCH 4.4 21/41] seccomp: fix the usage of get/put_seccomp_filter() in seccomp_get_filter() Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 22/41] arm64: Make sure SPsel is always set Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 23/41] arm64: fault: Route pte translation faults via do_translation_fault Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 25/41] kvm: nVMX: Dont allow L2 to access the hardware CR8 Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 26/41] PCI: Fix race condition with driver_override Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 27/41] btrfs: fix NULL pointer dereference from free_reloc_roots() Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 28/41] btrfs: propagate error to btrfs_cmp_data_prepare caller Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 29/41] btrfs: prevent to set invalid default subvolid Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 30/41] x86/fpu: Dont let userspace set bogus xcomp_bv Greg Kroah-Hartman
2017-10-03 12:21   ` [kernel-hardening] " Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 31/41] gfs2: Fix debugfs glocks dump Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 32/41] timer/sysclt: Restrict timer migration sysctl values to 0 and 1 Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 35/41] cxl: Fix driver use count Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 36/41] dmaengine: mmp-pdma: add number of requestors Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 37/41] ARM: pxa: add the number of DMA requestor lines Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 38/41] ARM: pxa: fix " Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 39/41] KVM: VMX: use cmpxchg64 Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 40/41] video: fbdev: aty: do not leak uninitialized padding in clk to userspace Greg Kroah-Hartman
2017-10-03 12:21 ` [PATCH 4.4 41/41] swiotlb-xen: implement xen_swiotlb_dma_mmap callback Greg Kroah-Hartman
2017-10-03 19:26 ` [PATCH 4.4 00/41] 4.4.90-stable review Shuah Khan
2017-10-03 20:30 ` Tom Gall
2017-10-04  7:55   ` Greg Kroah-Hartman
2017-10-04  8:29     ` Sumit Semwal
2017-10-03 20:41 ` Guenter Roeck

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