user/sven/linux.git/include/linux/sysctl.h, branch v5.10.76

all arch: remove system call sys_sysctl

2020-08-15T02:56:56Z

Since commit 61a47c1ad3a4dc ("sysctl: Remove the sysctl system call"), sys_sysctl is actually unavailable: any input can only return an error. We have been warning about people using the sysctl system call for years and believe there are no more users. Even if there are users of this interface if they have not complained or fixed their code by now they probably are not going to, so there is no point in warning them any longer. So completely remove sys_sysctl on all architectures. [nixiaoming@huawei.com: s390: fix build error for sys_call_table_emu] Link: http://lkml.kernel.org/r/20200618141426.16884-1-nixiaoming@huawei.com Signed-off-by: Xiaoming Ni Signed-off-by: Andrew Morton Acked-by: Will Deacon [arm/arm64] Acked-by: "Eric W. Biederman" Cc: Aleksa Sarai Cc: Alexander Shishkin Cc: Al Viro Cc: Andi Kleen Cc: Andrew Morton Cc: Andy Lutomirski Cc: Arnaldo Carvalho de Melo Cc: Arnd Bergmann Cc: Benjamin Herrenschmidt Cc: Bin Meng Cc: Borislav Petkov Cc: Brian Gerst Cc: Catalin Marinas Cc: chenzefeng Cc: Christian Borntraeger Cc: Christian Brauner Cc: Chris Zankel Cc: David Howells Cc: David S. Miller Cc: Diego Elio Pettenò Cc: Dmitry Vyukov Cc: Dominik Brodowski Cc: Fenghua Yu Cc: Geert Uytterhoeven Cc: Heiko Carstens Cc: Helge Deller Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Iurii Zaikin Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: Jiri Olsa Cc: Kars de Jong Cc: Kees Cook Cc: Krzysztof Kozlowski Cc: Luis Chamberlain Cc: Marco Elver Cc: Mark Rutland Cc: Martin K. Petersen Cc: Masahiro Yamada Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Miklos Szeredi Cc: Minchan Kim Cc: Namhyung Kim Cc: Naveen N. Rao Cc: Nick Piggin Cc: Oleg Nesterov Cc: Olof Johansson Cc: Paul Burton Cc: "Paul E. McKenney" Cc: Paul Mackerras Cc: Peter Zijlstra (Intel) Cc: Randy Dunlap Cc: Ravi Bangoria Cc: Richard Henderson Cc: Rich Felker Cc: Russell King Cc: Sami Tolvanen Cc: Sargun Dhillon Cc: Stephen Rothwell Cc: Sudeep Holla Cc: Sven Schnelle Cc: Thiago Jung Bauermann Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Tony Luck Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Yoshinori Sato Cc: Zhou Yanjie Link: http://lkml.kernel.org/r/20200616030734.87257-1-nixiaoming@huawei.com Signed-off-by: Linus Torvalds

kernel/sysctl: support setting sysctl parameters from kernel command line

2020-06-08T18:05:56Z

Patch series "support setting sysctl parameters from kernel command line", v3. This series adds support for something that seems like many people always wanted but nobody added it yet, so here's the ability to set sysctl parameters via kernel command line options in the form of sysctl.vm.something=1 The important part is Patch 1. The second, not so important part is an attempt to clean up legacy one-off parameters that do the same thing as a sysctl. I don't want to remove them completely for compatibility reasons, but with generic sysctl support the idea is to remove the one-off param handlers and treat the parameters as aliases for the sysctl variants. I have identified several parameters that mention sysctl counterparts in Documentation/admin-guide/kernel-parameters.txt but there might be more. The conversion also has varying level of success: - numa_zonelist_order is converted in Patch 2 together with adding the necessary infrastructure. It's easy as it doesn't really do anything but warn on deprecated value these days. - hung_task_panic is converted in Patch 3, but there's a downside that now it only accepts 0 and 1, while previously it was any integer value - nmi_watchdog maps to two sysctls nmi_watchdog and hardlockup_panic, so there's no straighforward conversion possible - traceoff_on_warning is a flag without value and it would be required to handle that somehow in the conversion infractructure, which seems pointless for a single flag This patch (of 5): A recently proposed patch to add vm_swappiness command line parameter in addition to existing sysctl [1] made me wonder why we don't have a general support for passing sysctl parameters via command line. Googling found only somebody else wondering the same [2], but I haven't found any prior discussion with reasons why not to do this. Settings the vm_swappiness issue aside (the underlying issue might be solved in a different way), quick search of kernel-parameters.txt shows there are already some that exist as both sysctl and kernel parameter - hung_task_panic, nmi_watchdog, numa_zonelist_order, traceoff_on_warning. A general mechanism would remove the need to add more of those one-offs and might be handy in situations where configuration by e.g. /etc/sysctl.d/ is impractical. Hence, this patch adds a new parse_args() pass that looks for parameters prefixed by 'sysctl.' and tries to interpret them as writes to the corresponding sys/ files using an temporary in-kernel procfs mount. This mechanism was suggested by Eric W. Biederman [3], as it handles all dynamically registered sysctl tables, even though we don't handle modular sysctls. Errors due to e.g. invalid parameter name or value are reported in the kernel log. The processing is hooked right before the init process is loaded, as some handlers might be more complicated than simple setters and might need some subsystems to be initialized. At the moment the init process can be started and eventually execute a process writing to /proc/sys/ then it should be also fine to do that from the kernel. Sysctls registered later on module load time are not set by this mechanism - it's expected that in such scenarios, setting sysctl values from userspace is practical enough. [1] https://lore.kernel.org/r/BL0PR02MB560167492CA4094C91589930E9FC0@BL0PR02MB5601.namprd02.prod.outlook.com/ [2] https://unix.stackexchange.com/questions/558802/how-to-set-sysctl-using-kernel-command-line-parameter [3] https://lore.kernel.org/r/87bloj2skm.fsf@x220.int.ebiederm.org/ Signed-off-by: Vlastimil Babka Signed-off-by: Andrew Morton Reviewed-by: Luis Chamberlain Reviewed-by: Masami Hiramatsu Acked-by: Kees Cook Acked-by: Michal Hocko Cc: Iurii Zaikin Cc: Ivan Teterevkov Cc: Michal Hocko Cc: David Rientjes Cc: Matthew Wilcox Cc: "Eric W . Biederman" Cc: "Guilherme G . Piccoli" Cc: Alexey Dobriyan Cc: Thomas Gleixner Cc: Greg Kroah-Hartman Cc: Christian Brauner Link: http://lkml.kernel.org/r/20200427180433.7029-1-vbabka@suse.cz Link: http://lkml.kernel.org/r/20200427180433.7029-2-vbabka@suse.cz Signed-off-by: Linus Torvalds

sysctl: pass kernel pointers to ->proc_handler

2020-04-27T06:07:40Z

Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig Acked-by: Andrey Ignatov Signed-off-by: Al Viro

sysctl: remove all extern declaration from sysctl.c

2020-04-27T06:06:53Z

Extern declarations in .c files are a bad style and can lead to mismatches. Use existing definitions in headers where they exist, and otherwise move the external declarations to suitable header files. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

include/linux/sysctl.h: inline braces for ctl_table and ctl_table_header

2019-12-05T03:44:11Z

Fix coding style of "struct ctl_table" and "struct ctl_table_header" to have inline braces. Besides the wide use of this proposed cose style, this change helps to find at a glance the struct definition when navigating the code. Link: http://lkml.kernel.org/r/20190903154906.188651-1-balsini@android.com Signed-off-by: Alessio Balsini Acked-by: Luis Chamberlain Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

proc/sysctl: add shared variables for range check

2019-07-19T00:08:07Z

In the sysctl code the proc_dointvec_minmax() function is often used to validate the user supplied value between an allowed range. This function uses the extra1 and extra2 members from struct ctl_table as minimum and maximum allowed value. On sysctl handler declaration, in every source file there are some readonly variables containing just an integer which address is assigned to the extra1 and extra2 members, so the sysctl range is enforced. The special values 0, 1 and INT_MAX are very often used as range boundary, leading duplication of variables like zero=0, one=1, int_max=INT_MAX in different source files: $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l 248 Add a const int array containing the most commonly used values, some macros to refer more easily to the correct array member, and use them instead of creating a local one for every object file. This is the bloat-o-meter output comparing the old and new binary compiled with the default Fedora config: # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164) Data old new delta sysctl_vals - 12 +12 __kstrtab_sysctl_vals - 12 +12 max 14 10 -4 int_max 16 - -16 one 68 - -68 zero 128 28 -100 Total: Before=20583249, After=20583085, chg -0.00% [mcroce@redhat.com: tipc: remove two unused variables] Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com [akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c] [arnd@arndb.de: proc/sysctl: make firmware loader table conditional] Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de [akpm@linux-foundation.org: fix fs/eventpoll.c] Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com Signed-off-by: Matteo Croce Signed-off-by: Arnd Bergmann Acked-by: Kees Cook Reviewed-by: Aaron Tomlin Cc: Matthew Wilcox Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sysctl: define proc_do_static_key()

2019-06-15T03:18:27Z

Convert proc_dointvec_minmax_bpf_stats() into a more generic helper, since we are going to use jump labels more often. Note that sysctl_bpf_stats_enabled is removed, since it is no longer needed/used. Signed-off-by: Eric Dumazet Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

pipe, sysctl: remove pipe_proc_fn()

2018-02-07T02:32:47Z

pipe_proc_fn() is no longer needed, as it only calls through to proc_dopipe_max_size(). Just put proc_dopipe_max_size() in the ctl_table entry directly, and remove the unneeded EXPORT_SYMBOL() and the ENOSYS stub for it. (The reason the ENOSYS stub isn't needed is that the pipe-max-size ctl_table entry is located directly in 'kern_table' rather than being registered separately. Therefore, the entry is already only defined when the kernel is built with sysctl support.) Link: http://lkml.kernel.org/r/20180111052902.14409-3-ebiggers3@gmail.com Signed-off-by: Eric Biggers Acked-by: Kees Cook Acked-by: Joe Lawrence Cc: Alexander Viro Cc: "Luis R . Rodriguez" Cc: Michael Kerrisk Cc: Mikulas Patocka Cc: Willy Tarreau Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pipe: add proc_dopipe_max_size() to safely assign pipe_max_size

2017-11-18T00:10:03Z

pipe_max_size is assigned directly via procfs sysctl: static struct ctl_table fs_table[] = { ... { .procname = "pipe-max-size", .data = &pipe_max_size, .maxlen = sizeof(int), .mode = 0644, .proc_handler = &pipe_proc_fn, .extra1 = &pipe_min_size, }, ... int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf, size_t *lenp, loff_t *ppos) { ... ret = proc_dointvec_minmax(table, write, buf, lenp, ppos) ... and then later rounded in-place a few statements later: ... pipe_max_size = round_pipe_size(pipe_max_size); ... This leaves a window of time between initial assignment and rounding that may be visible to other threads. (For example, one thread sets a non-rounded value to pipe_max_size while another reads its value.) Similar reads of pipe_max_size are potentially racy: pipe.c :: alloc_pipe_info() pipe.c :: pipe_set_size() Add a new proc_dopipe_max_size() that consolidates reading the new value from the user buffer, verifying bounds, and calling round_pipe_size() with a single assignment to pipe_max_size. Link: http://lkml.kernel.org/r/1507658689-11669-4-git-send-email-joe.lawrence@redhat.com Signed-off-by: Joe Lawrence Reported-by: Mikulas Patocka Reviewed-by: Mikulas Patocka Cc: Al Viro Cc: Jens Axboe Cc: Michael Kerrisk Cc: Randy Dunlap Cc: Josh Poimboeuf Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sysctl: add register_sysctl() dummy helper

2017-11-10T01:58:40Z

register_sysctl() has been around for five years with commit fea478d4101a ("sysctl: Add register_sysctl for normal sysctl users") but now that arm64 started using it, I ran into a compile error: arch/arm64/kernel/armv8_deprecated.c: In function 'register_insn_emulation_sysctl': arch/arm64/kernel/armv8_deprecated.c:257:2: error: implicit declaration of function 'register_sysctl' This adds a inline function like we already have for register_sysctl_paths() and register_sysctl_table(). Link: http://lkml.kernel.org/r/20171106133700.558647-1-arnd@arndb.de Fixes: 38b9aeb32fa7 ("arm64: Port deprecated instruction emulation to new sysctl interface") Signed-off-by: Arnd Bergmann Reviewed-by: Dave Martin Acked-by: Kees Cook Acked-by: Will Deacon Cc: Catalin Marinas Cc: "Luis R. Rodriguez" Cc: Alex Benne Cc: Arnd Bergmann Cc: "Eric W. Biederman" Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds