eec4844fae
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 <mcroce@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* net/dccp/sysctl.c
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*
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* An implementation of the DCCP protocol
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* Arnaldo Carvalho de Melo <acme@mandriva.com>
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*/
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#include <linux/mm.h>
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#include <linux/sysctl.h>
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#include "dccp.h"
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#include "feat.h"
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#ifndef CONFIG_SYSCTL
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#error This file should not be compiled without CONFIG_SYSCTL defined
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#endif
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/* Boundary values */
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static int u8_max = 0xFF;
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static unsigned long seqw_min = DCCPF_SEQ_WMIN,
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seqw_max = 0xFFFFFFFF; /* maximum on 32 bit */
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static struct ctl_table dccp_default_table[] = {
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{
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.procname = "seq_window",
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.data = &sysctl_dccp_sequence_window,
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.maxlen = sizeof(sysctl_dccp_sequence_window),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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.extra1 = &seqw_min, /* RFC 4340, 7.5.2 */
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.extra2 = &seqw_max,
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},
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{
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.procname = "rx_ccid",
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.data = &sysctl_dccp_rx_ccid,
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.maxlen = sizeof(sysctl_dccp_rx_ccid),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &u8_max, /* RFC 4340, 10. */
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},
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{
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.procname = "tx_ccid",
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.data = &sysctl_dccp_tx_ccid,
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.maxlen = sizeof(sysctl_dccp_tx_ccid),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &u8_max, /* RFC 4340, 10. */
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},
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{
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.procname = "request_retries",
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.data = &sysctl_dccp_request_retries,
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.maxlen = sizeof(sysctl_dccp_request_retries),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ONE,
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.extra2 = &u8_max,
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},
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{
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.procname = "retries1",
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.data = &sysctl_dccp_retries1,
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.maxlen = sizeof(sysctl_dccp_retries1),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &u8_max,
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},
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{
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.procname = "retries2",
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.data = &sysctl_dccp_retries2,
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.maxlen = sizeof(sysctl_dccp_retries2),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &u8_max,
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},
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{
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.procname = "tx_qlen",
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.data = &sysctl_dccp_tx_qlen,
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.maxlen = sizeof(sysctl_dccp_tx_qlen),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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},
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{
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.procname = "sync_ratelimit",
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.data = &sysctl_dccp_sync_ratelimit,
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.maxlen = sizeof(sysctl_dccp_sync_ratelimit),
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.mode = 0644,
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.proc_handler = proc_dointvec_ms_jiffies,
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},
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{ }
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};
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static struct ctl_table_header *dccp_table_header;
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int __init dccp_sysctl_init(void)
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{
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dccp_table_header = register_net_sysctl(&init_net, "net/dccp/default",
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dccp_default_table);
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return dccp_table_header != NULL ? 0 : -ENOMEM;
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}
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void dccp_sysctl_exit(void)
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{
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if (dccp_table_header != NULL) {
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unregister_net_sysctl_table(dccp_table_header);
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dccp_table_header = NULL;
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}
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}
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