- 25 May, 2017 40 commits
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Keno Fischer authored
commit 8310d48b upstream. In commit 19be0eaf ("mm: remove gup_flags FOLL_WRITE games from __get_user_pages()"), the mm code was changed from unsetting FOLL_WRITE after a COW was resolved to setting the (newly introduced) FOLL_COW instead. Simultaneously, the check in gup.c was updated to still allow writes with FOLL_FORCE set if FOLL_COW had also been set. However, a similar check in huge_memory.c was forgotten. As a result, remote memory writes to ro regions of memory backed by transparent huge pages cause an infinite loop in the kernel (handle_mm_fault sets FOLL_COW and returns 0 causing a retry, but follow_trans_huge_pmd bails out immidiately because `(flags & FOLL_WRITE) && !pmd_write(*pmd)` is true. While in this state the process is stil SIGKILLable, but little else works (e.g. no ptrace attach, no other signals). This is easily reproduced with the following code (assuming thp are set to always): #include <assert.h> #include <fcntl.h> #include <stdint.h> #include <stdio.h> #include <string.h> #include <sys/mman.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #define TEST_SIZE 5 * 1024 * 1024 int main(void) { int status; pid_t child; int fd = open("/proc/self/mem", O_RDWR); void *addr = mmap(NULL, TEST_SIZE, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); assert(addr != MAP_FAILED); pid_t parent_pid = getpid(); if ((child = fork()) == 0) { void *addr2 = mmap(NULL, TEST_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); assert(addr2 != MAP_FAILED); memset(addr2, 'a', TEST_SIZE); pwrite(fd, addr2, TEST_SIZE, (uintptr_t)addr); return 0; } assert(child == waitpid(child, &status, 0)); assert(WIFEXITED(status) && WEXITSTATUS(status) == 0); return 0; } Fix this by updating follow_trans_huge_pmd in huge_memory.c analogously to the update in gup.c in the original commit. The same pattern exists in follow_devmap_pmd. However, we should not be able to reach that check with FOLL_COW set, so add WARN_ONCE to make sure we notice if we ever do. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20170106015025.GA38411@juliacomputing.comSigned-off-by:
Keno Fischer <keno@juliacomputing.com> Acked-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Greg Thelen <gthelen@google.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> [AmitP: Minor refactoring of upstream changes for linux-3.18.y, where follow_devmap_pmd() doesn't exist.] Signed-off-by:
Amit Pundir <amit.pundir@linaro.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Takashi Iwai authored
commit 22a1e778 upstream. The commit 8dfbcc43 ("[media] xc2028: avoid use after free") tried to address the reported use-after-free by clearing the reference. However, it's clearing the wrong pointer; it sets NULL to priv->ctrl.fname, but it's anyway overwritten by the next line memcpy(&priv->ctrl, p, sizeof(priv->ctrl)). OTOH, the actual code accessing the freed string is the strcmp() call with priv->fname: if (!firmware_name[0] && p->fname && priv->fname && strcmp(p->fname, priv->fname)) free_firmware(priv); where priv->fname points to the previous file name, and this was already freed by kfree(). For fixing the bug properly, this patch does the following: - Keep the copy of firmware file name in only priv->fname, priv->ctrl.fname isn't changed; - The allocation is done only when the firmware gets loaded; - The kfree() is called in free_firmware() commonly Fixes: commit 8dfbcc43 ('[media] xc2028: avoid use after free') Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
Mauro Carvalho Chehab <mchehab@s-opensource.com> Signed-off-by:
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Kristina Martsenko authored
commit f0e421b1 upstream. Some kernel features don't currently work if a task puts a non-zero address tag in its stack pointer, frame pointer, or frame record entries (FP, LR). For example, with a tagged stack pointer, the kernel can't deliver signals to the process, and the task is killed instead. As another example, with a tagged frame pointer or frame records, perf fails to generate call graphs or resolve symbols. For now, just document these limitations, instead of finding and fixing everything that doesn't work, as it's not known if anyone needs to use tags in these places anyway. In addition, as requested by Dave Martin, generalize the limitations into a general kernel address tag policy, and refactor tagged-pointers.txt to include it. Fixes: d50240a5 ("arm64: mm: permit use of tagged pointers at EL0") Reviewed-by:
Dave Martin <Dave.Martin@arm.com> Acked-by:
Will Deacon <will.deacon@arm.com> Signed-off-by:
Kristina Martsenko <kristina.martsenko@arm.com> Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:
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Mark Rutland authored
commit a06040d7 upstream. Our access_ok() simply hands its arguments over to __range_ok(), which implicitly assummes that the addr parameter is 64 bits wide. This isn't necessarily true for compat code, which might pass down a 32-bit address parameter. In these cases, we don't have a guarantee that the address has been zero extended to 64 bits, and the upper bits of the register may contain unknown values, potentially resulting in a suprious failure. Avoid this by explicitly casting the addr parameter to an unsigned long (as is done on other architectures), ensuring that the parameter is widened appropriately. Fixes: 0aea86a2 ("arm64: User access library functions") Acked-by:
Mark Rutland <mark.rutland@arm.com> Signed-off-by:
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Mark Rutland authored
commit fee960be upstream. The inline assembly in __XCHG_CASE() uses a +Q constraint to hazard against other accesses to the memory location being exchanged. However, the pointer passed to the constraint is a u8 pointer, and thus the hazard only applies to the first byte of the location. GCC can take advantage of this, assuming that other portions of the location are unchanged, as demonstrated with the following test case: union u { unsigned long l; unsigned int i[2]; }; unsigned long update_char_hazard(union u *u) { unsigned int a, b; a = u->i[1]; asm ("str %1, %0" : "+Q" (*(char *)&u->l) : "r" (0UL)); b = u->i[1]; return a ^ b; } unsigned long update_long_hazard(union u *u) { unsigned int a, b; a = u->i[1]; asm ("str %1, %0" : "+Q" (*(long *)&u->l) : "r" (0UL)); b = u->i[1]; return a ^ b; } The linaro 15.08 GCC 5.1.1 toolchain compiles the above as follows when using -O2 or above: 0000000000000000 <update_char_hazard>: 0: d2800001 mov x1, #0x0 // #0 4: f9000001 str x1, [x0] 8: d2800000 mov x0, #0x0 // #0 c: d65f03c0 ret 0000000000000010 <update_long_hazard>: 10: b9400401 ldr w1, [x0,#4] 14: d2800002 mov x2, #0x0 // #0 18: f9000002 str x2, [x0] 1c: b9400400 ldr w0, [x0,#4] 20: 4a000020 eor w0, w1, w0 24: d65f03c0 ret This patch fixes the issue by passing an unsigned long pointer into the +Q constraint, as we do for our cmpxchg code. This may hazard against more than is necessary, but this is better than missing a necessary hazard. Fixes: 305d454a ("arm64: atomics: implement native {relaxed, acquire, release} atomics") Acked-by:
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Ludovic Desroches authored
commit d3df1ec0 upstream. Remove ADC channels that are not available by default on the sama5d3_xplained board (resistor not populated) in order to not create confusion. Signed-off-by:
Ludovic Desroches <ludovic.desroches@microchip.com> Acked-by:
Nicolas Ferre <nicolas.ferre@microchip.com> Signed-off-by:
Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by:
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Ludovic Desroches authored
commit 9cdd31e5 upstream. The voltage reference for the ADC is not 3V but 3.3V since it is connected to VDDANA. Signed-off-by:
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LiuHailong authored
commit fd615f69 upstream. Debug interrupts can be taken during interrupt entry, since interrupt entry does not automatically turn them off. The kernel will check whether the faulting instruction is between [interrupt_base_book3e, __end_interrupts], and if so clear MSR[DE] and return. However, when the kernel is built with CONFIG_RELOCATABLE, it can't use LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e) and LOAD_REG_IMMEDIATE(r15,__end_interrupts), as they ignore relocation. Thus, if the kernel is actually running at a different address than it was built at, the address comparison will fail, and the exception entry code will hang at kernel_dbg_exc. r2(toc) is also not usable here, as r2 still holds data from the interrupted context, so LOAD_REG_ADDR() doesn't work either. So we use the *name@got* to get the EV of two labels directly. Test programs test.c shows as follows: int main(int argc, char *argv[]) { if (access("/proc/sys/kernel/perf_event_paranoid", F_OK) == -1) printf("Kernel doesn't have perf_event support\n"); } Steps to reproduce the bug, for example: 1) ./gdb ./test 2) (gdb) b access 3) (gdb) r 4) (gdb) s Signed-off-by:
Liu Hailong <liu.hailong6@zte.com.cn> Signed-off-by:
Jiang Xuexin <jiang.xuexin@zte.com.cn> Reviewed-by:
Jiang Biao <jiang.biao2@zte.com.cn> Reviewed-by:
Liu Song <liu.song11@zte.com.cn> Reviewed-by:
Huang Jian <huang.jian@zte.com.cn> [scottwood: cleaned up commit message, and specified bad behavior as a hang rather than an oops to correspond to mainline kernel behavior] Fixes: 1cb6e064 ("powerpc/book3e: support CONFIG_RELOCATABLE") Signed-off-by:
Scott Wood <oss@buserror.net> Signed-off-by:
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Tyrel Datwyler authored
commit 68baf692 upstream. Historically struct device_node references were tracked using a kref embedded as a struct field. Commit 75b57ecf ("of: Make device nodes kobjects so they show up in sysfs") (Mar 2014) refactored device_nodes to be kobjects such that the device tree could by more simply exposed to userspace using sysfs. Commit 0829f6d1 ("of: device_node kobject lifecycle fixes") (Mar 2014) followed up these changes to better control the kobject lifecycle and in particular the referecne counting via of_node_get(), of_node_put(), and of_node_init(). A result of this second commit was that it introduced an of_node_put() call when a dynamic node is detached, in of_node_remove(), that removes the initial kobj reference created by of_node_init(). Traditionally as the original dynamic device node user the pseries code had assumed responsibilty for releasing this final reference in its platform specific DLPAR detach code. This patch fixes a refcount underflow introduced by commit 0829f6d1, and recently exposed by the upstreaming of the recount API. Messages like the following are no longer seen in the kernel log with this patch following DLPAR remove operations of cpus and pci devices. rpadlpar_io: slot PHB 72 removed refcount_t: underflow; use-after-free. ------------[ cut here ]------------ WARNING: CPU: 5 PID: 3335 at lib/refcount.c:128 refcount_sub_and_test+0xf4/0x110 Fixes: 0829f6d1 ("of: device_node kobject lifecycle fixes") Signed-off-by:
Tyrel Datwyler <tyreld@linux.vnet.ibm.com> [mpe: Make change log commit references more verbose] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
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Mahesh Salgaonkar authored
commit d93b0ac0 upstream. machine_check_early() gets called in real mode. The very first time when add_taint() is called, it prints a warning which ends up calling opal call (that uses OPAL_CALL wrapper) for writing it to console. If we get a very first machine check while we are in opal we are doomed. OPAL_CALL overwrites the PACASAVEDMSR in r13 and in this case when we are done with MCE handling the original opal call will use this new MSR on it's way back to opal_return. This usually leads to unexpected behaviour or the kernel to panic. Instead move the add_taint() call later in the virtual mode where it is safe to call. This is broken with current FW level. We got lucky so far for not getting very first MCE hit while in OPAL. But easily reproducible on Mambo. Fixes: 27ea2c42 ("powerpc: Set the correct kernel taint on machine check errors.") Signed-off-by:
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by:
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Johan Hovold authored
commit 0cd273bb upstream. Make sure to check the number of endpoints to avoid dereferencing a NULL-pointer or accessing memory beyond the endpoint array should a malicious device lack the expected endpoints. Fixes: e0d3bafd ("V4L/DVB (10954): Add cx231xx USB driver") Cc: Sri Deevi <Srinivasa.Deevi@conexant.com> Signed-off-by:
Johan Hovold <johan@kernel.org> Signed-off-by:
Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by:
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Johan Hovold authored
commit 65f92164 upstream. Make sure to check the number of endpoints to avoid dereferencing a NULL-pointer or accessing memory beyond the endpoint array should a malicious device lack the expected endpoints. Fixes: e0d3bafd ("V4L/DVB (10954): Add cx231xx USB driver") Cc: Sri Deevi <Srinivasa.Deevi@conexant.com> Signed-off-by:
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Johan Hovold authored
commit fff1abc4 upstream. Make sure to release the snd_card also on a late allocation error. Fixes: e0d3bafd ("V4L/DVB (10954): Add cx231xx USB driver") Cc: Sri Deevi <Srinivasa.Deevi@conexant.com> Signed-off-by:
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Daniel Scheller authored
commit 158f0328 upstream. Fixes "w_scan -f c" complaining with This dvb driver is *buggy*: the symbol rate limits are undefined - please report to linuxtv.org) Signed-off-by:
Daniel Scheller <d.scheller@gmx.net> Acked-by:
Abylay Ospan <aospan@netup.ru> Signed-off-by:
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Alyssa Milburn authored
commit ee0fe833 upstream. This code copies actual_length-128 bytes from the header, which will underflow if the received buffer is too small. Signed-off-by:
Alyssa Milburn <amilburn@zall.org> Signed-off-by:
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Johan Hovold authored
commit d5823511 upstream. Make sure to check the number of endpoints to avoid dereferencing a NULL-pointer should a malicious device lack endpoints. Fixes: c4018fa2 ("[media] dib0700: fix RC support on Hauppauge Nova-TD") Cc: Mauro Carvalho Chehab <mchehab@kernel.org> Signed-off-by:
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Marek Szyprowski authored
commit a5cb00eb upstream. Clock should be turned off after calling s5p_mfc_init_hw() from the watchdog worker, like it is already done in the s5p_mfc_open() which also calls this function. Fixes: af935746 ("[media] MFC: Add MFC 5.1 V4L2 driver") Signed-off-by:
Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by:
Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by:
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Johan Hovold authored
commit aa58fedb upstream. Make sure to check the number of endpoints to avoid accessing memory beyond the endpoint array should a device lack the expected endpoints. Note that, as far as I can tell, the gspca framework has already made sure there is at least one endpoint in the current alternate setting so there should be no risk for a NULL-pointer dereference here. Fixes: b517af72 ("V4L/DVB: gspca_konica: New gspca subdriver for konica chipset using cams") Cc: Hans de Goede <hdegoede@redhat.com> Signed-off-by:
Hans Verkuil <hansverk@cisco.com> Signed-off-by:
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Yan, Zheng authored
commit 8179a101 upstream. ceph_set_acl() calls __ceph_setattr() if the setacl operation needs to modify inode's i_mode. __ceph_setattr() updates inode's i_mode, then calls posix_acl_chmod(). The problem is that __ceph_setattr() calls posix_acl_chmod() before sending the setattr request. The get_acl() call in posix_acl_chmod() can trigger a getxattr request. The reply of the getxattr request can restore inode's i_mode to its old value. The set_acl() call in posix_acl_chmod() sees old value of inode's i_mode, so it calls __ceph_setattr() again. Cc: stable@vger.kernel.org # needs backporting for < 4.9 Link: http://tracker.ceph.com/issues/19688Reported-by:
Jerry Lee <leisurelysw24@gmail.com> Signed-off-by:
"Yan, Zheng" <zyan@redhat.com> Reviewed-by:
Jeff Layton <jlayton@redhat.com> Tested-by:
Luis Henriques <lhenriques@suse.com> Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> [luis: introduce __ceph_setattr() and make ceph_set_acl() call it, as suggested by Yan.] Signed-off-by:
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Matt Ranostay authored
commit 84ca8e36 upstream. AS3935_WRITE_DATA macro bit is incorrect and the actual write sequence is two leading zeros. Cc: George McCollister <george.mccollister@gmail.com> Signed-off-by:
Matt Ranostay <matt.ranostay@konsulko.com> Signed-off-by:
Jonathan Cameron <jic23@kernel.org> Signed-off-by:
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Dan Carpenter authored
commit ee0d8d84 upstream. We should call ipxitf_put() if the copy_to_user() fails. Reported-by:
李强 <liqiang6-s@360.cn> Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
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Johan Hovold authored
commit bec444cd upstream. Add missing sanity check on the non-SuperSpeed hub-descriptor length in order to avoid parsing and leaking two bytes of uninitialised slab data through sysfs removable-attributes (or a compound-device debug statement). Note that we only make sure that the DeviceRemovable field is always present (and specifically ignore the unused PortPwrCtrlMask field) in order to continue support any hubs with non-compliant descriptors. As a further safeguard, the descriptor buffer is also cleared. Fixes: 1da177e4 ("Linux-2.6.12-rc2") Signed-off-by:
Alan Stern <stern@rowland.harvard.edu> Signed-off-by:
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Johan Hovold authored
commit 2c25a2c8 upstream. A SuperSpeed hub descriptor does not have any variable-length fields so bail out when reading a short descriptor. This avoids parsing and leaking two bytes of uninitialised slab data through sysfs removable-attributes. Fixes: dbe79bbe ("USB 3.0 Hub Changes") Cc: John Youn <John.Youn@synopsys.com> Acked-by:
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Johan Hovold authored
commit 6aeb75e6 upstream. Fix a division-by-zero in set_termios when debugging is enabled and a high-enough speed has been requested so that the divisor value becomes zero. Instead of just fixing the offending debug statement, cap the baud rate at the base as a zero divisor value also appears to crash the firmware. Fixes: 1da177e4 ("Linux-2.6.12-rc2") Reviewed-by:
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Johan Hovold authored
commit 26cede34 upstream. Drop erroneous cpu_to_le32 when setting the baud rate, something which corrupted the divisor on big-endian hosts. Found using sparse: warning: incorrect type in argument 1 (different base types) expected unsigned int [unsigned] [usertype] val got restricted __le32 [usertype] <noident> Fixes: af2ac1a0 ("USB: serial mct_usb232: move DMA buffers to heap") Reviewed-by:
Pete Zaitcev <zaitcev@yahoo.com> Signed-off-by:
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Bjørn Mork authored
commit 8d7a10dd upstream. In their infinite wisdom, and never ending quest for end user frustration, Lenovo has decided to use new USB device IDs for the wwan modules in their 2017 laptops. The actual hardware is still the Sierra Wireless EM7455 or EM7430, depending on region. Signed-off-by:
Bjørn Mork <bjorn@mork.no> Signed-off-by:
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Daniele Palmas authored
commit 40dd4604 upstream. This patch adds support for Telit ME910 PID 0x1100. Signed-off-by:
Daniele Palmas <dnlplm@gmail.com> Signed-off-by:
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Johan Hovold authored
commit dd5ca753 upstream. Drop erroneous le16_to_cpu when returning the USB device speed which is already in host byte order. Found using sparse: warning: cast to restricted __le16 Fixes: 946b960d ("USB: add driver for iowarrior devices.") Signed-off-by:
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Peter Ujfalusi authored
commit 6df2b42f upstream. We have one register for each EP to set the maximum packet size for both TX and RX. If for example an RX programming would happen before the previous TX transfer finishes we would reset the TX packet side. To fix this issue, only modify the TX or RX part of the register. Fixes: 550a7375 ("USB: Add MUSB and TUSB support") Signed-off-by:
Peter Ujfalusi <peter.ujfalusi@ti.com> Tested-by:
Tony Lindgren <tony@atomide.com> Signed-off-by:
Bin Liu <b-liu@ti.com> Signed-off-by:
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Alyssa Milburn authored
commit a12b8ab8 upstream. Otherwise ttusb2_i2c_xfer can read or write beyond the end of static and heap buffers. Signed-off-by:
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Johan Hovold authored
commit 03eb2a55 upstream. Make sure to check for the required out endpoint to avoid dereferencing a NULL-pointer in mce_request_packet should a malicious device lack such an endpoint. Note that this path is hit during probe. Fixes: 66e89522 ("V4L/DVB: IR: add mceusb IR receiver driver") Signed-off-by:
Sean Young <sean@mess.org> Signed-off-by:
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Johan Hovold authored
commit eacb975b upstream. Make sure to check the number of endpoints to avoid dereferencing a NULL-pointer or accessing memory beyond the endpoint array should a malicious device lack the expected endpoints. Fixes: 2a9f8b5d ("V4L/DVB (5206): Usbvision: set alternate interface modification") Cc: Thierry MERLE <thierry.merle@free.fr> Signed-off-by:
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Johan Hovold authored
commit 75cf0679 upstream. Add missing endianness conversion when using the USB device-descriptor bcdDevice field to construct a firmware file name. Fixes: 8ef80aef ("[IRDA]: irda-usb.c: STIR421x cleanups") Cc: Nick Fedchik <nfedchik@atlantic-link.com.ua> Signed-off-by:
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Peter Chen authored
commit 7480d912 upstream. According to xHCI ch4.20 Scratchpad Buffers, the Scratchpad Buffer needs to be zeroed. ... The following operations take place to allocate Scratchpad Buffers to the xHC: ... b. Software clears the Scratchpad Buffer to '0' Signed-off-by:
Peter Chen <peter.chen@nxp.com> Signed-off-by:
Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by:
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Mathias Nyman authored
commit a0c16630 upstream. Intel Denverton microserver is Atom based and need the PME and CAS quirks as well. Signed-off-by:
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Thomas Petazzoni authored
commit 4b148d51 upstream. platform_get_irq() returns an error code, but the xhci-plat driver ignores it and always returns -ENODEV. This is not correct, and prevents -EPROBE_DEFER from being propagated properly. Signed-off-by:
Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by:
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Konstantin Khlebnikov authored
commit 094f4691 upstream. Cgroup created inside throttled group must inherit current throttle_count. Broken throttle_count allows to nominate throttled entries as a next buddy, later this leads to null pointer dereference in pick_next_task_fair(). This patch initialize cfs_rq->throttle_count at first enqueue: laziness allows to skip locking all rq at group creation. Lazy approach also allows to skip full sub-tree scan at throttling hierarchy (not in this patch). Signed-off-by:
Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bsegall@google.com Link: http://lkml.kernel.org/r/146608182119.21870.8439834428248129633.stgit@buzzSigned-off-by:
Ingo Molnar <mingo@kernel.org> Cc: Ben Pineau <benjamin.pineau@mirakl.com> Signed-off-by:
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Konstantin Khlebnikov authored
commit 754bd598 upstream. Hierarchy could be already throttled at this point. Throttled next buddy could trigger a NULL pointer dereference in pick_next_task_fair(). Signed-off-by:
Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/146608183552.21905.15924473394414832071.stgit@buzzSigned-off-by:
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Eric Biggers authored
commit 6b06cdee upstream. When accessing an encrypted directory without the key, userspace must operate on filenames derived from the ciphertext names, which contain arbitrary bytes. Since we must support filenames as long as NAME_MAX, we can't always just base64-encode the ciphertext, since that may make it too long. Currently, this is solved by presenting long names in an abbreviated form containing any needed filesystem-specific hashes (e.g. to identify a directory block), then the last 16 bytes of ciphertext. This needs to be sufficient to identify the actual name on lookup. However, there is a bug. It seems to have been assumed that due to the use of a CBC (ciphertext block chaining)-based encryption mode, the last 16 bytes (i.e. the AES block size) of ciphertext would depend on the full plaintext, preventing collisions. However, we actually use CBC with ciphertext stealing (CTS), which handles the last two blocks specially, causing them to appear "flipped". Thus, it's actually the second-to-last block which depends on the full plaintext. This caused long filenames that differ only near the end of their plaintexts to, when observed without the key, point to the wrong inode and be undeletable. For example, with ext4: # echo pass | e4crypt add_key -p 16 edir/ # seq -f "edir/abcdefghijklmnopqrstuvwxyz012345%.0f" 100000 | xargs touch # find edir/ -type f | xargs stat -c %i | sort | uniq | wc -l 100000 # sync # echo 3 > /proc/sys/vm/drop_caches # keyctl new_session # find edir/ -type f | xargs stat -c %i | sort | uniq | wc -l 2004 # rm -rf edir/ rm: cannot remove 'edir/_A7nNFi3rhkEQlJ6P,hdzluhODKOeWx5V': Structure needs cleaning ... To fix this, when presenting long encrypted filenames, encode the second-to-last block of ciphertext rather than the last 16 bytes. Although it would be nice to solve this without depending on a specific encryption mode, that would mean doing a cryptographic hash like SHA-256 which would be much less efficient. This way is sufficient for now, and it's still compatible with encryption modes like HEH which are strong pseudorandom permutations. Also, changing the presented names is still allowed at any time because they are only provided to allow applications to do things like delete encrypted directories. They're not designed to be used to persistently identify files --- which would be hard to do anyway, given that they're encrypted after all. For ease of backports, this patch only makes the minimal fix to both ext4 and f2fs. It leaves ubifs as-is, since ubifs doesn't compare the ciphertext block yet. Follow-on patches will clean things up properly and make the filesystems use a shared helper function. Fixes: 5de0b4d0 ("ext4 crypto: simplify and speed up filename encryption") Reported-by:
Gwendal Grignou <gwendal@chromium.org> Signed-off-by:
Eric Biggers <ebiggers@google.com> Signed-off-by:
Theodore Ts'o <tytso@mit.edu> Signed-off-by:
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Jaegeuk Kim authored
commit 6332cd32 upstream. If user has no key under an encrypted dir, fscrypt gives digested dentries. Previously, when looking up a dentry, f2fs only checks its hash value with first 4 bytes of the digested dentry, which didn't handle hash collisions fully. This patch enhances to check entire dentry bytes likewise ext4. Eric reported how to reproduce this issue by: # seq -f "edir/abcdefghijklmnopqrstuvwxyz012345%.0f" 100000 | xargs touch # find edir -type f | xargs stat -c %i | sort | uniq | wc -l 100000 # sync # echo 3 > /proc/sys/vm/drop_caches # keyctl new_session # find edir -type f | xargs stat -c %i | sort | uniq | wc -l 99999 Cc: <stable@vger.kernel.org> Reported-by:
Jaegeuk Kim <jaegeuk@kernel.org> (fixed f2fs_dentry_hash() to work even when the hash is 0) Signed-off-by:
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