- 12 Jul, 2017 40 commits
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Kees Cook authored
No callers remain for ipc_rcu_alloc(). Drop the function. [manfred@colorfullife.com: Rediff because the memset was temporarily inside ipc_rcu_free()] Link: http://lkml.kernel.org/r/20170525185107.12869-13-manfred@colorfullife.comSigned-off-by:
Kees Cook <keescook@chromium.org> Signed-off-by:
Manfred Spraul <manfred@colorfullife.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Kees Cook authored
Instead of using ipc_rcu_alloc() which only performs the refcount bump, open code it. This also allows for msg_queue structure layout to be randomized in the future. Link: http://lkml.kernel.org/r/20170525185107.12869-12-manfred@colorfullife.comSigned-off-by:
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Kees Cook authored
Instead of using ipc_rcu_alloc() which only performs the refcount bump, open code it. This also allows for shmid_kernel structure layout to be randomized in the future. Link: http://lkml.kernel.org/r/20170525185107.12869-11-manfred@colorfullife.comSigned-off-by:
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Kees Cook authored
Instead of using ipc_rcu_alloc() which only performs the refcount bump, open code it to perform better sem-specific checks. This also allows for sem_array structure layout to be randomized in the future. [manfred@colorfullife.com: Rediff, because the memset was temporarily inside ipc_rcu_alloc()] Link: http://lkml.kernel.org/r/20170525185107.12869-10-manfred@colorfullife.comSigned-off-by:
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Kees Cook authored
There are no more callers of ipc_rcu_free(), so remove it. Link: http://lkml.kernel.org/r/20170525185107.12869-9-manfred@colorfullife.comSigned-off-by:
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Kees Cook authored
Avoid using ipc_rcu_free, since it just re-finds the original structure pointer. For the pre-list-init failure path, there is no RCU needed, since it was just allocated. It can be directly freed. Link: http://lkml.kernel.org/r/20170525185107.12869-8-manfred@colorfullife.comSigned-off-by:
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Kees Cook authored
Avoid using ipc_rcu_free, since it just re-finds the original structure pointer. For the pre-list-init failure path, there is no RCU needed, since it was just allocated. It can be directly freed. Link: http://lkml.kernel.org/r/20170525185107.12869-7-manfred@colorfullife.comSigned-off-by:
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Kees Cook authored
Avoid using ipc_rcu_free, since it just re-finds the original structure pointer. For the pre-list-init failure path, there is no RCU needed, since it was just allocated. It can be directly freed. Link: http://lkml.kernel.org/r/20170525185107.12869-6-manfred@colorfullife.comSigned-off-by:
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Kees Cook authored
The only users of ipc_alloc() were ipc_rcu_alloc() and the on-heap sem_io fall-back memory. Better to just open-code these to make things easier to read. [manfred@colorfullife.com: Rediff due to inclusion of memset() into ipc_rcu_alloc()] Link: http://lkml.kernel.org/r/20170525185107.12869-5-manfred@colorfullife.comSigned-off-by:
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Manfred Spraul authored
sem_ctime is initialized to the semget() time and then updated at every semctl() that changes the array. Thus it does not represent the time of the last change. Especially, semop() calls are only stored in sem_otime, not in sem_ctime. This is already described in ipc/sem.c, I just overlooked that there is a comment in include/linux/sem.h and man semctl(2) as well. So: Correct wrong comments. Link: http://lkml.kernel.org/r/20170515171912.6298-4-manfred@colorfullife.comSigned-off-by:
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Manfred Spraul authored
ipc has two management structures that exist for every id: - struct kern_ipc_perm, it contains e.g. the permissions. - struct ipc_rcu, it contains the rcu head for rcu handling and the refcount. The patch merges both structures. As a bonus, we may save one cacheline, because both structures are cacheline aligned. In addition, it reduces the number of casts, instead most codepaths can use container_of. To simplify code, the ipc_rcu_alloc initializes the allocation to 0. [manfred@colorfullife.com: really include the memset() into ipc_alloc_rcu()] Link: http://lkml.kernel.org/r/564f8612-0601-b267-514f-a9f650ec9b32@colorfullife.com Link: http://lkml.kernel.org/r/20170525185107.12869-3-manfred@colorfullife.comSigned-off-by:
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Manfred Spraul authored
sma->sem_base is initialized with sma->sem_base = (struct sem *) &sma[1]; The current code has four problems: - There is an unnecessary pointer dereference - sem_base is not needed. - Alignment for struct sem only works by chance. - The current code causes false positive for static code analysis. - This is a cast between different non-void types, which the future randstruct GCC plugin warns on. And, as bonus, the code size gets smaller: Before: 0 .text 00003770 After: 0 .text 0000374e [manfred@colorfullife.com: s/[0]/[]/, per hch] Link: http://lkml.kernel.org/r/20170525185107.12869-2-manfred@colorfullife.com Link: http://lkml.kernel.org/r/20170515171912.6298-2-manfred@colorfullife.comSigned-off-by: -
Dmitry Vyukov authored
Add /proc/self/task/<current-tid>/fail-nth file that allows failing 0-th, 1-st, 2-nd and so on calls systematically. Excerpt from the added documentation: "Write to this file of integer N makes N-th call in the current task fail (N is 0-based). Read from this file returns a single char 'Y' or 'N' that says if the fault setup with a previous write to this file was injected or not, and disables the fault if it wasn't yet injected. Note that this file enables all types of faults (slab, futex, etc). This setting takes precedence over all other generic settings like probability, interval, times, etc. But per-capability settings (e.g. fail_futex/ignore-private) take precedence over it. This feature is intended for systematic testing of faults in a single system call. See an example below" Why add a new setting: 1. Existing settings are global rather than per-task. So parallel testing is not possible. 2. attr->interval is close but it depends on attr->count which is non reset to 0, so interval does not work as expected. 3. Trying to model this with existing settings requires manipulations of all of probability, interval, times, space, task-filter and unexposed count and per-task make-it-fail files. 4. Existing settings are per-failure-type, and the set of failure types is potentially expanding. 5. make-it-fail can't be changed by unprivileged user and aggressive stress testing better be done from an unprivileged user. Similarly, this would require opening the debugfs files to the unprivileged user, as he would need to reopen at least times file (not possible to pre-open before dropping privs). The proposed interface solves all of the above (see the example). We want to integrate this into syzkaller fuzzer. A prototype has found 10 bugs in kernel in first day of usage: https://groups.google.com/forum/#!searchin/syzkaller/%22FAULT_INJECTION%22%7Csort:relevance I've made the current interface work with all types of our sandboxes. For setuid the secret sauce was prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) to make /proc entries non-root owned. So I am fine with the current version of the code. [akpm@linux-foundation.org: fix build] Link: http://lkml.kernel.org/r/20170328130128.101773-1-dvyukov@google.comSigned-off-by:
Dmitry Vyukov <dvyukov@google.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by:
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Cyrill Gorcunov authored
kcmp syscall is build iif CONFIG_CHECKPOINT_RESTORE is selected, so wrap appropriate helpers in epoll code with the config to build it conditionally. Link: http://lkml.kernel.org/r/20170513083456.GG1881@uranus.lanSigned-off-by:
Cyrill Gorcunov <gorcunov@openvz.org> Reported-by:
Andrew Morton <akpm@linuxfoundation.org> Cc: Andrey Vagin <avagin@openvz.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by:
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Cyrill Gorcunov authored
With current epoll architecture target files are addressed with file_struct and file descriptor number, where the last is not unique. Moreover files can be transferred from another process via unix socket, added into queue and closed then so we won't find this descriptor in the task fdinfo list. Thus to checkpoint and restore such processes CRIU needs to find out where exactly the target file is present to add it into epoll queue. For this sake one can use kcmp call where some particular target file from the queue is compared with arbitrary file passed as an argument. Because epoll target files can have same file descriptor number but different file_struct a caller should explicitly specify the offset within. To test if some particular file is matching entry inside epoll one have to - fill kcmp_epoll_slot structure with epoll file descriptor, target file number and target file offset (in case if only one target is present then it should be 0) - call kcmp as kcmp(pid1, pid2, KCMP_EPOLL_TFD, fd, &kcmp_epoll_slot) - the kernel fetch file pointer matching file descriptor @fd of pid1 - lookups for file struct in epoll queue of pid2 and returns traditional 0,1,2 result for sorting purpose Link: http://lkml.kernel.org/r/20170424154423.511592110@gmail.comSigned-off-by:Andrey Vagin <avagin@openvz.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by:
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Cyrill Gorcunov authored
Since it is possbile to have same number in tfd field (say file added, closed, then nother file dup'ed to same number and added back) it is imposible to distinguish such target files solely by their numbers. Strictly speaking regular applications don't need to recognize these targets at all but for checkpoint/restore sake we need to collect targets to be able to push them back on restore stage in a proper order. Thus lets add file position, inode and device number where this target lays. This three fields can be used as a primary key for sorting, and together with kcmp help CRIU can find out an exact file target (from the whole set of processes being checkpointed). Link: http://lkml.kernel.org/r/20170424154423.436491881@gmail.comSigned-off-by:
Andrei Vagin <avagin@virtuozzo.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by:
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Logan Gunthorpe authored
This is a layering violation so we replace the uses with calls to sg_page(). This is a prep patch for replacing page_link and this is one of the very few uses outside of scatterlist.h. Link: http://lkml.kernel.org/r/1495663199-22234-1-git-send-email-logang@deltatee.comSigned-off-by:
Logan Gunthorpe <logang@deltatee.com> Signed-off-by:
Stephen Bates <sbates@raithlin.com> Acked-by:
Stefani Seibold <stefani@seibold.net> Cc: Stefani Seibold <stefani@seibold.net> Cc: Greg KH <greg@kroah.com> Signed-off-by:
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Leonard Crestez authored
Use errors=replace because it is never desirable for lx-dmesg to fail on string decoding errors, not even if the log buffer is corrupt and we show incorrect info. The kernel will sometimes print utf8, for example the copyright symbol from jffs2. In order to make this work specify 'utf8' everywhere because python2 otherwise defaults to 'ascii'. In theory the second errors='replace' is not be required because everything that can be decoded as utf8 should also be encodable back to utf8. But it's better to be extra safe here. It's worth noting that this is definitely not true for encoding='ascii', unknown characters are replaced with U+FFFD REPLACEMENT CHARACTER and they fail to encode back to ascii. Link: http://lkml.kernel.org/r/acee067f3345954ed41efb77b80eebdc038619c6.1498481469.git.leonard.crestez@nxp.comSigned-off-by:
Leonard Crestez <leonard.crestez@nxp.com> Acked-by:
Jan Kiszka <jan.kiszka@siemens.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Kieran Bingham <kieran@ksquared.org.uk> Signed-off-by:
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Leonard Crestez authored
In some cases it is possible for the str() conversion here to throw encoding errors because log_buf might not point to valid ascii. For example: (gdb) python print str(gdb.parse_and_eval("log_buf")) Traceback (most recent call last): File "<string>", line 1, in <module> UnicodeEncodeError: 'ascii' codec can't encode character u'\u0303' in position 24: ordinal not in range(128) Avoid this by explicitly casting to (void *) inside the gdb expression. Link: http://lkml.kernel.org/r/ba6f85dbb02ca980ebd0e2399b0649423399b565.1498481469.git.leonard.crestez@nxp.comSigned-off-by: -
Peter Griffin authored
lx-fdtdump dumps the flattened device tree passed to the kernel from the bootloader to the filename specified as the command argument. If no argument is provided it defaults to fdtdump.dtb. This then allows further post processing on the machine running GDB. The fdt header is also also printed in the GDB console. For example: (gdb) lx-fdtdump fdt_magic: 0xD00DFEED fdt_totalsize: 0xC108 off_dt_struct: 0x38 off_dt_strings: 0x3804 off_mem_rsvmap: 0x28 version: 17 last_comp_version: 16 Dumped fdt to fdtdump.dtb >fdtdump fdtdump.dtb | less This command is useful as the bootloader can often re-write parts of the device tree, and this can sometimes cause the kernel to not boot. Link: http://lkml.kernel.org/r/1481280065-5336-2-git-send-email-kbingham@kernel.orgSigned-off-by:
Peter Griffin <peter.griffin@linaro.org> Signed-off-by:
Kieran Bingham <kbingham@kernel.org> Cc: Jason Wessel <jason.wessel@windriver.com> Signed-off-by:
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Davidlohr Bueso authored
As of commit bf3eac84 ("percpu-rwsem: kill CONFIG_PERCPU_RWSEM") we unconditionally build pcpu-rwsems. Remove a leftover in for FILE_LOCKING. Link: http://lkml.kernel.org/r/20170518180115.2794-1-dave@stgolabs.netSigned-off-by:
Davidlohr Bueso <dbueso@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by:
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Rakesh Pandit authored
Mount fails if file system image has empty files because of sanity check while reading superblock. For empty files disk offset to end of file (i_eoffset) is cpu_to_le32(-1). Sanity check comparison, which compares disk offset with file system size isn't valid for this value and hence is ignored with this patch. Steps to reproduce: $ dd if=/dev/zero of=bfs-image count=204800 $ mkfs.bfs bfs-image $ mkdir bfs-mount-point $ sudo mount -t bfs -o loop bfs-image bfs-mount-point/ $ cd bfs-mount-point/ $ sudo touch a $ cd .. $ sudo umount bfs-mount-point/ $ sudo mount -t bfs -o loop bfs-image bfs-mount-point/ mount: /dev/loop0: can't read superblock $ dmesg [25526.689580] BFS-fs: bfs_fill_super(): Inode 0x00000003 corrupted Tigran said: "If you had created the filesystem with the proper mkfs under SCO UnixWare 7 you (probably) wouldn't encounter this issue. But since commercial Unix-es are now part of history and the only proper way is the Linux mkfs.bfs utility, your patch is fine" Link: http://lkml.kernel.org/r/20170505201625.GA3097@hercules.tuxera.comSigned-off-by:
Rakesh Pandit <rakesh@tuxera.com> Acked-by:
Tigran Aivazian <aivazian.tigran@gmail.com> Signed-off-by:
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Kees Cook authored
The add_device_randomness() function would ignore incoming bytes if the crng wasn't ready. This additionally makes sure to make an early enough call to add_latent_entropy() to influence the initial stack canary, which is especially important on non-x86 systems where it stays the same through the life of the boot. Link: http://lkml.kernel.org/r/20170626233038.GA48751@beastSigned-off-by:
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Mateusz Jurczyk authored
Prevent use of uninitialized memory (originating from the stack frame of do_sysctl()) by verifying that the name array is filled with sufficient input data before comparing its specific entries with integer constants. Through timing measurement or analyzing the kernel debug logs, a user-mode program could potentially infer the results of comparisons against the uninitialized memory, and acquire some (very limited) information about the state of the kernel stack. The change also eliminates possible future warnings by tools such as KMSAN and other code checkers / instrumentations. Link: http://lkml.kernel.org/r/20170524122139.21333-1-mjurczyk@google.comSigned-off-by:
Mateusz Jurczyk <mjurczyk@google.com> Acked-by:
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Luis R. Rodriguez authored
Add a few initial respective tests for an array: o Echoing values separated by spaces works o Echoing only first elements will set first elements o Confirm PAGE_SIZE limit still applies even if an array is used Link: http://lkml.kernel.org/r/20170630224431.17374-7-mcgrof@kernel.orgSigned-off-by:
Luis R. Rodriguez <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by:
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Luis R. Rodriguez authored
Test against a simple proc_douintvec() case. While at it, add a test against UINT_MAX. Make sure UINT_MAX works, and UINT_MAX+1 will fail and that negative values are not accepted. Link: http://lkml.kernel.org/r/20170630224431.17374-6-mcgrof@kernel.orgSigned-off-by:
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Luis R. Rodriguez authored
Test against a simple proc_dointvec() case. While at it, add a test against INT_MAX. Make sure INT_MAX works, and INT_MAX+1 will fail. Also test negative values work. Link: http://lkml.kernel.org/r/20170630224431.17374-5-mcgrof@kernel.orgSigned-off-by:
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Luis R. Rodriguez authored
Add the following tests to ensure we do not regress: o Test using a buffer full of space (PAGE_SIZE-1) followed by a single digit works o Test using a buffer full of spaces (PAGE_SIZE or over) will fail As tests increase instead of unloading the module and reloading it we can just do a shell reset_vals() with a reset to values we know are set at init on the driver. Link: http://lkml.kernel.org/r/20170630224431.17374-4-mcgrof@kernel.orgSigned-off-by: -
Luis R. Rodriguez authored
This adds a generic script to let us more easily add more tests cases. Since we really have only two types of tests cases just fold them into the one file. Each test unit is now identified into its separate function: # ./sysctl.sh -l Test ID list: TEST_ID x NUM_TEST TEST_ID: Test ID NUM_TESTS: Number of recommended times to run the test 0001 x 1 - tests proc_dointvec_minmax() 0002 x 1 - tests proc_dostring() For now we start off with what we had before, and run only each test once. We can now watch a test case until it fails: ./sysctl.sh -w 0002 We can also run a test case x number of times, say we want to run a test case 100 times: ./sysctl.sh -c 0001 100 To run a test case only once, for example: ./sysctl.sh -s 0002 The default settings are specified at the top of sysctl.sh. Link: http://lkml.kernel.org/r/20170630224431.17374-3-mcgrof@kernel.orgSigned-off-by: -
Luis R. Rodriguez authored
The existing tools/testing/selftests/sysctl/ tests include two test cases, but these use existing production kernel sysctl interfaces. We want to expand test coverage but we can't just be looking for random safe production values to poke at, that's just insane! Instead just dedicate a test driver for debugging purposes and port the existing scripts to use it. This will make it easier for further tests to be added. Subsequent patches will extend our test coverage for sysctl. The stress test driver uses a new license (GPL on Linux, copyleft-next outside of Linux). Linus was fine with this [0] and later due to Ted's and Alans's request ironed out an "or" language clause to use [1] which is already present upstream. [0] https://lkml.kernel.org/r/CA+55aFyhxcvD+q7tp+-yrSFDKfR0mOHgyEAe=f_94aKLsOu0Og@mail.gmail.com [1] https://lkml.kernel.org/r/1495234558.7848.122.camel@linux.intel.com Link: http://lkml.kernel.org/r/20170630224431.17374-2-mcgrof@kernel.orgSigned-off-by:
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Luis R. Rodriguez authored
To keep parity with regular int interfaces provide the an unsigned int proc_douintvec_minmax() which allows you to specify a range of allowed valid numbers. Adding proc_douintvec_minmax_sysadmin() is easy but we can wait for an actual user for that. Link: http://lkml.kernel.org/r/20170519033554.18592-6-mcgrof@kernel.orgSigned-off-by:
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Luis R. Rodriguez authored
Commit e7d316a0 ("sysctl: handle error writing UINT_MAX to u32 fields") added proc_douintvec() to start help adding support for unsigned int, this however was only half the work needed. Two fixes have come in since then for the following issues: o Printing the values shows a negative value, this happens since do_proc_dointvec() and this uses proc_put_long() This was fixed by commit 5380e564 ("sysctl: don't print negative flag for proc_douintvec"). o We can easily wrap around the int values: UINT_MAX is 4294967295, if we echo in 4294967295 + 1 we end up with 0, using 4294967295 + 2 we end up with 1. o We echo negative values in and they are accepted This was fixed by commit 425fffd8 ("sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec"). It still also failed to be added to sysctl_check_table()... instead of adding it with the current implementation just provide a proper and simplified unsigned int support without any array unsigned int support with no negative support at all. Historically sysctl proc helpers have supported arrays, due to the complexity this adds though we've taken a step back to evaluate array users to determine if its worth upkeeping for unsigned int. An evaluation using Coccinelle has been done to perform a grammatical search to ask ourselves: o How many sysctl proc_dointvec() (int) users exist which likely should be moved over to proc_douintvec() (unsigned int) ? Answer: about 8 - Of these how many are array users ? Answer: Probably only 1 o How many sysctl array users exist ? Answer: about 12 This last question gives us an idea just how popular arrays: they are not. Array support should probably just be kept for strings. The identified uint ports are: drivers/infiniband/core/ucma.c - max_backlog drivers/infiniband/core/iwcm.c - default_backlog net/core/sysctl_net_core.c - rps_sock_flow_sysctl() net/netfilter/nf_conntrack_timestamp.c - nf_conntrack_timestamp -- bool net/netfilter/nf_conntrack_acct.c nf_conntrack_acct -- bool net/netfilter/nf_conntrack_ecache.c - nf_conntrack_events -- bool net/netfilter/nf_conntrack_helper.c - nf_conntrack_helper -- bool net/phonet/sysctl.c proc_local_port_range() The only possible array users is proc_local_port_range() but it does not seem worth it to add array support just for this given the range support works just as well. Unsigned int support should be desirable more for when you *need* more than INT_MAX or using int min/max support then does not suffice for your ranges. If you forget and by mistake happen to register an unsigned int proc entry with an array, the driver will fail and you will get something as follows: sysctl table check failed: debug/test_sysctl//uint_0002 array now allowed CPU: 2 PID: 1342 Comm: modprobe Tainted: G W E <etc> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS <etc> Call Trace: dump_stack+0x63/0x81 __register_sysctl_table+0x350/0x650 ? kmem_cache_alloc_trace+0x107/0x240 __register_sysctl_paths+0x1b3/0x1e0 ? 0xffffffffc005f000 register_sysctl_table+0x1f/0x30 test_sysctl_init+0x10/0x1000 [test_sysctl] do_one_initcall+0x52/0x1a0 ? kmem_cache_alloc_trace+0x107/0x240 do_init_module+0x5f/0x200 load_module+0x1867/0x1bd0 ? __symbol_put+0x60/0x60 SYSC_finit_module+0xdf/0x110 SyS_finit_module+0xe/0x10 entry_SYSCALL_64_fastpath+0x1e/0xad RIP: 0033:0x7f042b22d119 <etc> Fixes: e7d316a0 ("sysctl: handle error writing UINT_MAX to u32 fields") Link: http://lkml.kernel.org/r/20170519033554.18592-5-mcgrof@kernel.orgSigned-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> Cc: Liping Zhang <zlpnobody@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Kees Cook <keescook@chromium.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
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Luis R. Rodriguez authored
The mode sysctl_writes_strict positional checks keep being copy and pasted as we add new proc handlers. Just add a helper to avoid code duplication. Link: http://lkml.kernel.org/r/20170519033554.18592-4-mcgrof@kernel.orgSigned-off-by:
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Luis R. Rodriguez authored
Document the different sysctl_writes_strict modes in code. Link: http://lkml.kernel.org/r/20170519033554.18592-3-mcgrof@kernel.orgSigned-off-by:
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Luis R. Rodriguez authored
Patch series "sysctl: few fixes", v5. I've been working on making kmod more deterministic, and as I did that I couldn't help but notice a few issues with sysctl. My end goal was just to fix unsigned int support, which back then was completely broken. Liping Zhang has sent up small atomic fixes, however it still missed yet one more fix and Alexey Dobriyan had also suggested to just drop array support given its complexity. I have inspected array support using Coccinelle and indeed its not that popular, so if in fact we can avoid it for new interfaces, I agree its best. I did develop a sysctl stress driver but will hold that off for another series. This patch (of 5): Commit 7c60c48f ("sysctl: Improve the sysctl sanity checks") improved sanity checks considerbly, however the enhancements on sysctl_check_table() meant adding a functional change so that only the last table entry's sanity error is propagated. It also changed the way errors were propagated so that each new check reset the err value, this means only last sanity check computed is used for an error. This has been in the kernel since v3.4 days. Fix this by carrying on errors from previous checks and iterations as we traverse the table and ensuring we keep any error from previous checks. We keep iterating on the table even if an error is found so we can complain for all errors found in one shot. This works as -EINVAL is always returned on error anyway, and the check for error is any non-zero value. Fixes: 7c60c48f ("sysctl: Improve the sysctl sanity checks") Link: http://lkml.kernel.org/r/20170519033554.18592-2-mcgrof@kernel.orgSigned-off-by:
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Bharat Bhushan authored
Minor updates in Documentation for arm64 as relocatable kernel. Also this patch updates documentation for using uncompressed image "Image" which is used for ARM64. Link: http://lkml.kernel.org/r/1495104793-6563-1-git-send-email-Bharat.Bhushan@nxp.comSigned-off-by:
Bharat Bhushan <Bharat.Bhushan@nxp.com> Cc: Dave Young <dyoung@redhat.com> Cc: Baoquan He <bhe@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Pratyush Anand <panand@redhat.com> Signed-off-by:
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Xunlei Pang authored
Currently vmcoreinfo data is updated at boot time subsys_initcall(), it has the risk of being modified by some wrong code during system is running. As a result, vmcore dumped may contain the wrong vmcoreinfo. Later on, when using "crash", "makedumpfile", etc utility to parse this vmcore, we probably will get "Segmentation fault" or other unexpected errors. E.g. 1) wrong code overwrites vmcoreinfo_data; 2) further crashes the system; 3) trigger kdump, then we obviously will fail to recognize the crash context correctly due to the corrupted vmcoreinfo. Now except for vmcoreinfo, all the crash data is well protected(including the cpu note which is fully updated in the crash path, thus its correctness is guaranteed). Given that vmcoreinfo data is a large chunk prepared for kdump, we better protect it as well. To solve this, we relocate and copy vmcoreinfo_data to the crash memory when kdump is loading via kexec syscalls. Because the whole crash memory will be protected by existing arch_kexec_protect_crashkres() mechanism, we naturally protect vmcoreinfo_data from write(even read) access under kernel direct mapping after kdump is loaded. Since kdump is usually loaded at the very early stage after boot, we can trust the correctness of the vmcoreinfo data copied. On the other hand, we still need to operate the vmcoreinfo safe copy when crash happens to generate vmcoreinfo_note again, we rely on vmap() to map out a new kernel virtual address and update to use this new one instead in the following crash_save_vmcoreinfo(). BTW, we do not touch vmcoreinfo_note, because it will be fully updated using the protected vmcoreinfo_data after crash which is surely correct just like the cpu crash note. Link: http://lkml.kernel.org/r/1493281021-20737-3-git-send-email-xlpang@redhat.comSigned-off-by:
Xunlei Pang <xlpang@redhat.com> Tested-by:
Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Young <dyoung@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Juergen Gross <jgross@suse.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by:
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Xunlei Pang authored
vmcoreinfo_max_size stands for the vmcoreinfo_data, the correct one we should use is vmcoreinfo_note whose total size is VMCOREINFO_NOTE_SIZE. Like explained in commit 77019967 ("kdump: fix exported size of vmcoreinfo note"), it should not affect the actual function, but we better fix it, also this change should be safe and backward compatible. After this, we can get rid of variable vmcoreinfo_max_size, let's use the corresponding macros directly, fewer variables means more safety for vmcoreinfo operation. [xlpang@redhat.com: fix build warning] Link: http://lkml.kernel.org/r/1494830606-27736-1-git-send-email-xlpang@redhat.com Link: http://lkml.kernel.org/r/1493281021-20737-2-git-send-email-xlpang@redhat.comSigned-off-by:
Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Reviewed-by:
Dave Young <dyoung@redhat.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Juergen Gross <jgross@suse.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by:
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Xunlei Pang authored
As Eric said, "what we need to do is move the variable vmcoreinfo_note out of the kernel's .bss section. And modify the code to regenerate and keep this information in something like the control page. Definitely something like this needs a page all to itself, and ideally far away from any other kernel data structures. I clearly was not watching closely the data someone decided to keep this silly thing in the kernel's .bss section." This patch allocates extra pages for these vmcoreinfo_XXX variables, one advantage is that it enhances some safety of vmcoreinfo, because vmcoreinfo now is kept far away from other kernel data structures. Link: http://lkml.kernel.org/r/1493281021-20737-1-git-send-email-xlpang@redhat.comSigned-off-by:
Juergen Gross <jgross@suse.com> Suggested-by:
Eric Biederman <ebiederm@xmission.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Young <dyoung@redhat.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by:
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Christoph Lameter authored
The reason to disable interrupts seems to be to avoid switching to a different processor while handling per cpu data using individual loads and stores. If we use per cpu RMV primitives we will not have to disable interrupts. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1705171055130.5898@east.gentwo.orgSigned-off-by:
Christoph Lameter <cl@linux.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by:
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