user/sven/linux.git/include, branch v4.14.281

Reinstate some of "swiotlb: rework "fix info leak with DMA_FROM_DEVICE""

2022-05-25T06:41:22Z

commit 901c7280ca0d5e2b4a8929fbe0bfb007ac2a6544 upstream. Halil Pasic points out [1] that the full revert of that commit (revert in bddac7c1e02b), and that a partial revert that only reverts the problematic case, but still keeps some of the cleanups is probably better. And that partial revert [2] had already been verified by Oleksandr Natalenko to also fix the issue, I had just missed that in the long discussion. So let's reinstate the cleanups from commit aa6f8dcbab47 ("swiotlb: rework "fix info leak with DMA_FROM_DEVICE""), and effectively only revert the part that caused problems. Link: https://lore.kernel.org/all/20220328013731.017ae3e3.pasic@linux.ibm.com/ [1] Link: https://lore.kernel.org/all/20220324055732.GB12078@lst.de/ [2] Link: https://lore.kernel.org/all/4386660.LvFx2qVVIh@natalenko.name/ [3] Suggested-by: Halil Pasic Tested-by: Oleksandr Natalenko Cc: Christoph Hellwig" Signed-off-by: Linus Torvalds [OP: backport to 4.14: apply swiotlb_tbl_map_single() changes in lib/swiotlb.c] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

swiotlb: fix info leak with DMA_FROM_DEVICE

2022-05-25T06:41:22Z

commit ddbd89deb7d32b1fbb879f48d68fda1a8ac58e8e upstream. The problem I'm addressing was discovered by the LTP test covering cve-2018-1000204. A short description of what happens follows: 1) The test case issues a command code 00 (TEST UNIT READY) via the SG_IO interface with: dxfer_len == 524288, dxdfer_dir == SG_DXFER_FROM_DEV and a corresponding dxferp. The peculiar thing about this is that TUR is not reading from the device. 2) In sg_start_req() the invocation of blk_rq_map_user() effectively bounces the user-space buffer. As if the device was to transfer into it. Since commit a45b599ad808 ("scsi: sg: allocate with __GFP_ZERO in sg_build_indirect()") we make sure this first bounce buffer is allocated with GFP_ZERO. 3) For the rest of the story we keep ignoring that we have a TUR, so the device won't touch the buffer we prepare as if the we had a DMA_FROM_DEVICE type of situation. My setup uses a virtio-scsi device and the buffer allocated by SG is mapped by the function virtqueue_add_split() which uses DMA_FROM_DEVICE for the "in" sgs (here scatter-gather and not scsi generics). This mapping involves bouncing via the swiotlb (we need swiotlb to do virtio in protected guest like s390 Secure Execution, or AMD SEV). 4) When the SCSI TUR is done, we first copy back the content of the second (that is swiotlb) bounce buffer (which most likely contains some previous IO data), to the first bounce buffer, which contains all zeros. Then we copy back the content of the first bounce buffer to the user-space buffer. 5) The test case detects that the buffer, which it zero-initialized, ain't all zeros and fails. One can argue that this is an swiotlb problem, because without swiotlb we leak all zeros, and the swiotlb should be transparent in a sense that it does not affect the outcome (if all other participants are well behaved). Copying the content of the original buffer into the swiotlb buffer is the only way I can think of to make swiotlb transparent in such scenarios. So let's do just that if in doubt, but allow the driver to tell us that the whole mapped buffer is going to be overwritten, in which case we can preserve the old behavior and avoid the performance impact of the extra bounce. Signed-off-by: Halil Pasic Signed-off-by: Christoph Hellwig [OP: backport to 4.14: apply swiotlb_tbl_map_single() changes in lib/swiotlb.c] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

net: Fix features skip in for_each_netdev_feature()

2022-05-18T07:18:05Z

[ Upstream commit 85db6352fc8a158a893151baa1716463d34a20d0 ] The find_next_netdev_feature() macro gets the "remaining length", not bit index. Passing "bit - 1" for the following iteration is wrong as it skips the adjacent bit. Pass "bit" instead. Fixes: 3b89ea9c5902 ("net: Fix for_each_netdev_feature on Big endian") Signed-off-by: Tariq Toukan Reviewed-by: Gal Pressman Link: https://lore.kernel.org/r/20220504080914.1918-1-tariqt@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ALSA: pcm: Fix potential AB/BA lock with buffer_mutex and mmap_lock

2022-05-15T17:40:27Z

commit bc55cfd5718c7c23e5524582e9fa70b4d10f2433 upstream. syzbot caught a potential deadlock between the PCM runtime->buffer_mutex and the mm->mmap_lock. It was brought by the recent fix to cover the racy read/write and other ioctls, and in that commit, I overlooked a (hopefully only) corner case that may take the revert lock, namely, the OSS mmap. The OSS mmap operation exceptionally allows to re-configure the parameters inside the OSS mmap syscall, where mm->mmap_mutex is already held. Meanwhile, the copy_from/to_user calls at read/write operations also take the mm->mmap_lock internally, hence it may lead to a AB/BA deadlock. A similar problem was already seen in the past and we fixed it with a refcount (in commit b248371628aa). The former fix covered only the call paths with OSS read/write and OSS ioctls, while we need to cover the concurrent access via both ALSA and OSS APIs now. This patch addresses the problem above by replacing the buffer_mutex lock in the read/write operations with a refcount similar as we've used for OSS. The new field, runtime->buffer_accessing, keeps the number of concurrent read/write operations. Unlike the former buffer_mutex protection, this protects only around the copy_from/to_user() calls; the other codes are basically protected by the PCM stream lock. The refcount can be a negative, meaning blocked by the ioctls. If a negative value is seen, the read/write aborts with -EBUSY. In the ioctl side, OTOH, they check this refcount, too, and set to a negative value for blocking unless it's already being accessed. Reported-by: syzbot+6e5c88838328e99c7e1c@syzkaller.appspotmail.com Fixes: dca947d4d26d ("ALSA: pcm: Fix races among concurrent read/write and buffer changes") Cc: Link: https://lore.kernel.org/r/000000000000381a0d05db622a81@google.com Link: https://lore.kernel.org/r/20220330120903.4738-1-tiwai@suse.de Signed-off-by: Takashi Iwai [OP: backport to 4.14: adjusted context] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

ALSA: pcm: Fix races among concurrent hw_params and hw_free calls

2022-05-15T17:40:27Z

commit 92ee3c60ec9fe64404dc035e7c41277d74aa26cb upstream. Currently we have neither proper check nor protection against the concurrent calls of PCM hw_params and hw_free ioctls, which may result in a UAF. Since the existing PCM stream lock can't be used for protecting the whole ioctl operations, we need a new mutex to protect those racy calls. This patch introduced a new mutex, runtime->buffer_mutex, and applies it to both hw_params and hw_free ioctl code paths. Along with it, the both functions are slightly modified (the mmap_count check is moved into the state-check block) for code simplicity. Reported-by: Hu Jiahui Cc: Reviewed-by: Jaroslav Kysela Link: https://lore.kernel.org/r/20220322170720.3529-2-tiwai@suse.de Signed-off-by: Takashi Iwai [OP: backport to 4.14: adjusted context] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

Bluetooth: Fix the creation of hdev->name

2022-05-15T17:40:26Z

commit 103a2f3255a95991252f8f13375c3a96a75011cd upstream. Set a size limit of 8 bytes of the written buffer to "hdev->name" including the terminating null byte, as the size of "hdev->name" is 8 bytes. If an id value which is greater than 9999 is allocated, then the "snprintf(hdev->name, sizeof(hdev->name), "hci%d", id)" function call would lead to a truncation of the id value in decimal notation. Set an explicit maximum id parameter in the id allocation function call. The id allocation function defines the maximum allocated id value as the maximum id parameter value minus one. Therefore, HCI_MAX_ID is defined as 10000. Signed-off-by: Itay Iellin Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman

tcp: fix potential xmit stalls caused by TCP_NOTSENT_LOWAT

2022-05-12T10:17:07Z

[ Upstream commit 4bfe744ff1644fbc0a991a2677dc874475dd6776 ] I had this bug sitting for too long in my pile, it is time to fix it. Thanks to Doug Porter for reminding me of it! We had various attempts in the past, including commit 0cbe6a8f089e ("tcp: remove SOCK_QUEUE_SHRUNK"), but the issue is that TCP stack currently only generates EPOLLOUT from input path, when tp->snd_una has advanced and skb(s) cleaned from rtx queue. If a flow has a big RTT, and/or receives SACKs, it is possible that the notsent part (tp->write_seq - tp->snd_nxt) reaches 0 and no more data can be sent until tp->snd_una finally advances. What is needed is to also check if POLLOUT needs to be generated whenever tp->snd_nxt is advanced, from output path. This bug triggers more often after an idle period, as we do not receive ACK for at least one RTT. tcp_notsent_lowat could be a fraction of what CWND and pacing rate would allow to send during this RTT. In a followup patch, I will remove the bogus call to tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED) from tcp_check_space(). Fact that we have decided to generate an EPOLLOUT does not mean the application has immediately refilled the transmit queue. This optimistic call might have been the reason the bug seemed not too serious. Tested: 200 ms rtt, 1% packet loss, 32 MB tcp_rmem[2] and tcp_wmem[2] $ echo 500000 >/proc/sys/net/ipv4/tcp_notsent_lowat $ cat bench_rr.sh SUM=0 for i in {1..10} do V=`netperf -H remote_host -l30 -t TCP_RR -- -r 10000000,10000 -o LOCAL_BYTES_SENT | egrep -v "MIGRATED|Bytes"` echo $V SUM=$(($SUM + $V)) done echo SUM=$SUM Before patch: $ bench_rr.sh 130000000 80000000 140000000 140000000 140000000 140000000 130000000 40000000 90000000 110000000 SUM=1140000000 After patch: $ bench_rr.sh 430000000 590000000 530000000 450000000 450000000 350000000 450000000 490000000 480000000 460000000 SUM=4680000000 # This is 410 % of the value before patch. Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option") Signed-off-by: Eric Dumazet Reported-by: Doug Porter Cc: Soheil Hassas Yeganeh Cc: Neal Cardwell Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

hex2bin: make the function hex_to_bin constant-time

2022-05-12T10:17:06Z

commit e5be15767e7e284351853cbaba80cde8620341fb upstream. The function hex2bin is used to load cryptographic keys into device mapper targets dm-crypt and dm-integrity. It should take constant time independent on the processed data, so that concurrently running unprivileged code can't infer any information about the keys via microarchitectural convert channels. This patch changes the function hex_to_bin so that it contains no branches and no memory accesses. Note that this shouldn't cause performance degradation because the size of the new function is the same as the size of the old function (on x86-64) - and the new function causes no branch misprediction penalties. I compile-tested this function with gcc on aarch64 alpha arm hppa hppa64 i386 ia64 m68k mips32 mips64 powerpc powerpc64 riscv sh4 s390x sparc32 sparc64 x86_64 and with clang on aarch64 arm hexagon i386 mips32 mips64 powerpc powerpc64 s390x sparc32 sparc64 x86_64 to verify that there are no branches in the generated code. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

ax25: fix reference count leaks of ax25_dev

2022-04-27T11:15:32Z

commit 87563a043cef044fed5db7967a75741cc16ad2b1 upstream. The previous commit d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs") introduces refcount into ax25_dev, but there are reference leak paths in ax25_ctl_ioctl(), ax25_fwd_ioctl(), ax25_rt_add(), ax25_rt_del() and ax25_rt_opt(). This patch uses ax25_dev_put() and adjusts the position of ax25_addr_ax25dev() to fix reference cout leaks of ax25_dev. Fixes: d01ffb9eee4a ("ax25: add refcount in ax25_dev to avoid UAF bugs") Signed-off-by: Duoming Zhou Reviewed-by: Dan Carpenter Link: https://lore.kernel.org/r/20220203150811.42256-1-duoming@zju.edu.cn Signed-off-by: Jakub Kicinski [OP: backport to 4.14: adjust context] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman

ax25: add refcount in ax25_dev to avoid UAF bugs

2022-04-27T11:15:31Z

commit d01ffb9eee4af165d83b08dd73ebdf9fe94a519b upstream. If we dereference ax25_dev after we call kfree(ax25_dev) in ax25_dev_device_down(), it will lead to concurrency UAF bugs. There are eight syscall functions suffer from UAF bugs, include ax25_bind(), ax25_release(), ax25_connect(), ax25_ioctl(), ax25_getname(), ax25_sendmsg(), ax25_getsockopt() and ax25_info_show(). One of the concurrency UAF can be shown as below: (USE) | (FREE) | ax25_device_event | ax25_dev_device_down ax25_bind | ... ... | kfree(ax25_dev) ax25_fillin_cb() | ... ax25_fillin_cb_from_dev() | ... | The root cause of UAF bugs is that kfree(ax25_dev) in ax25_dev_device_down() is not protected by any locks. When ax25_dev, which there are still pointers point to, is released, the concurrency UAF bug will happen. This patch introduces refcount into ax25_dev in order to guarantee that there are no pointers point to it when ax25_dev is released. Signed-off-by: Duoming Zhou Signed-off-by: David S. Miller [OP: backport to 4.14: adjusted context] Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman