kernel/git/stable/linux.git/arch/um, branch linux-5.18.y

um: random: Don't initialise hwrng struct with zero

2022-08-17T12:41:49+00:00

[ Upstream commit 9e70cbd11b03889c92462cf52edb2bd023c798fa ] Initialising the hwrng struct with zeros causes a compile-time sparse warning: $ ARCH=um make -j10 W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ... CHECK arch/um/drivers/random.c arch/um/drivers/random.c:31:31: sparse: warning: Using plain integer as NULL pointer Fix the warning by not initialising the hwrng struct with zeros as it is initialised anyway during module init. Fixes: 72d3e093afae ("um: random: Register random as hwrng-core device") Reported-by: kernel test robot Signed-off-by: Christopher Obbard Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

um: seed rng using host OS rng

2022-08-17T12:40:14+00:00

commit 0b9ba6135d7f18b82f3d8bebb55ded725ba88e0e upstream. UML generally does not provide access to special CPU instructions like RDRAND, and execution tends to be rather deterministic, with no real hardware interrupts, making good randomness really very hard, if not all together impossible. Not only is this a security eyebrow raiser, but it's also quite annoying when trying to do various pieces of UML-based automation that takes a long time to boot, if ever. Fix this by trivially calling getrandom() in the host and using that seed as "bootloader randomness", which initializes the rng immediately at UML boot. The old behavior can be restored the same way as on any other arch, by way of CONFIG_TRUST_BOOTLOADER_RANDOMNESS=n or random.trust_bootloader=0. So seen from that perspective, this just makes UML act like other archs, which is positive in its own right. Additionally, wire up arch_get_random_{int,long}() in the same way, so that reseeds can also make use of the host RNG, controllable by CONFIG_TRUST_CPU_RANDOMNESS and random.trust_cpu, per usual. Cc: stable@vger.kernel.org Acked-by: Johannes Berg Acked-By: Anton Ivanov Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

um: Remove straying parenthesis

2022-08-17T12:40:14+00:00

commit c6496e0a4a90d8149203c16323cff3fa46e422e7 upstream. Commit e3a33af812c6 ("um: fix and optimize xor select template for CONFIG64 and timetravel mode") caused a build regression when CONFIG_XOR_BLOCKS and CONFIG_UML_TIME_TRAVEL_SUPPORT are selected. Fix it by removing the straying parenthesis. Cc: stable@vger.kernel.org Fixes: e3a33af812c6 ("um: fix and optimize xor select template for CONFIG64 and timetravel mode") Signed-off-by: Benjamin Beichler [rw: Added commit message] Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

um: Add missing apply_returns()

2022-07-23T10:57:00+00:00

commit 564d998106397394b6aad260f219b882b3347e62 upstream. Implement apply_returns() stub for UM, just like all the other patching routines. Fixes: 15e67227c49a ("x86: Undo return-thunk damage") Reported-by: Randy Dunlap Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/Ys%2Ft45l%2FgarIrD0u@worktop.programming.kicks-ass.net Signed-off-by: Greg Kroah-Hartman

um: line: Use separate IRQs per line

2022-06-14T16:45:13+00:00

[ Upstream commit d5a9597d6916a76663085db984cb8fe97f0a5c56 ] Today, all possible serial lines (ssl*=) as well as all possible consoles (con*=) each share a single interrupt (with a fixed number) with others of the same type. Now, if you have two lines, say ssl0 and ssl1, and one of them is connected to an fd you cannot read (e.g. a file), but the other gets a read interrupt, then both of them get the interrupt since it's shared. Then, the read() call will return EOF, since it's a file being written and there's nothing to read (at least not at the current offset, at the end). Unfortunately, this is treated as a read error, and we close this line, losing all the possible output. It might be possible to work around this and make the IRQ sharing work, however, now that we have dynamically allocated IRQs that are easy to use, simply use that to achieve separating between the events; then there's no interrupt for that line and we never attempt the read in the first place, thus not closing the line. This manifested itself in the wifi hostap/hwsim tests where the parallel script communicates via one serial console and the kernel messages go to another (a file) and sending data on the communication console caused the kernel messages to stop flowing into the file. Reported-by: Jouni Malinen Signed-off-by: Johannes Berg Acked-By: anton ivanov Signed-off-by: Richard Weinberger Signed-off-by: Sasha Levin

um: chan_user: Fix winch_tramp() return value

2022-06-09T08:30:50+00:00

commit 57ae0b67b747031bc41fb44643aa5344ab58607e upstream. The previous fix here was only partially correct, it did result in returning a proper error value in case of error, but it also clobbered the pid that we need to return from this function (not just zero for success). As a result, it returned 0 here, but later this is treated as a pid and used to kill the process, but since it's now 0 we kill(0, SIGKILL), which makes UML kill itself rather than just the helper thread. Fix that and make it more obvious by using a separate variable for the pid. Fixes: ccf1236ecac4 ("um: fix error return code in winch_tramp()") Reported-and-tested-by: Nathan Chancellor Signed-off-by: Johannes Berg Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

um: Use asm-generic/dma-mapping.h

2022-06-09T08:30:50+00:00

commit 365719035526e8eda214a1cedb2e1c96e969a0d7 upstream. If DMA (PCI over virtio) is enabled, then some drivers may enable CONFIG_DMA_OPS as well, and then we pull in the x86 definition of get_arch_dma_ops(), which uses the dma_ops symbol, which isn't defined. Since we don't have real DMA ops nor any kind of IOMMU fix this in the simplest possible way: pull in the asm-generic file instead of inheriting the x86 one. It's not clear why those drivers that do (e.g. VDPA) "select DMA_OPS", and if they'd even work with this, but chances are nobody will be wanting to do that anyway, so fixing the build failure is good enough. Reported-by: Randy Dunlap Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver") Signed-off-by: Johannes Berg Tested-by: Randy Dunlap Acked-by: Randy Dunlap Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

um: virtio_uml: Fix broken device handling in time-travel

2022-06-09T08:30:50+00:00

commit af9fb41ed315ce95f659f0b10b4d59a71975381d upstream. If a device implementation crashes, virtio_uml will mark it as dead by calling virtio_break_device() and scheduling the work that will remove it. This still seems like the right thing to do, but it's done directly while reading the message, and if time-travel is used, this is in the time-travel handler, outside of the normal Linux machinery. Therefore, we cannot acquire locks or do normal "linux-y" things because e.g. lockdep will be confused about the context. Move handling this situation out of the read function and into the actual IRQ handler and response handling instead, so that in the case of time-travel we don't call it in the wrong context. Chances are the system will still crash immediately, since the device implementation crashing may also cause the time- travel controller to go down, but at least all of that now happens without strange warnings from lockdep. Fixes: c8177aba37ca ("um: time-travel: rework interrupt handling in ext mode") Cc: stable@vger.kernel.org Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger Signed-off-by: Greg Kroah-Hartman

ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP

2022-06-09T08:29:30+00:00

commit c200e4bb44e80b343c09841e7caaaca0aac5e5fa upstream. User mode linux is the last user of the PT_DTRACE flag. Using the flag to indicate single stepping is a little confusing and worse changing tsk->ptrace without locking could potentionally cause problems. So use a thread info flag with a better name instead of flag in tsk->ptrace. Remove the definition PT_DTRACE as uml is the last user. Cc: stable@vger.kernel.org Acked-by: Johannes Berg Tested-by: Kees Cook Reviewed-by: Oleg Nesterov Link: https://lkml.kernel.org/r/20220505182645.497868-3-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

um: use fallback for random_get_entropy() instead of zero

2022-05-30T07:24:05+00:00

commit 9f13fb0cd11ed2327abff69f6501a2c124c88b5a upstream. In the event that random_get_entropy() can't access a cycle counter or similar, falling back to returning 0 is really not the best we can do. Instead, at least calling random_get_entropy_fallback() would be preferable, because that always needs to return _something_, even falling back to jiffies eventually. It's not as though random_get_entropy_fallback() is super high precision or guaranteed to be entropic, but basically anything that's not zero all the time is better than returning zero all the time. This is accomplished by just including the asm-generic code like on other architectures, which means we can get rid of the empty stub function here. Cc: Thomas Gleixner Cc: Arnd Bergmann Cc: Richard Weinberger Cc: Anton Ivanov Acked-by: Johannes Berg Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman