ce9d9b8e5c
the returned buffer of register_sysctl() is stored into net_header variable, but net_header is not used after, and compiler maybe optimise the variable out, and lead kmemleak reported the below warning comm "swapper/0", pid 1, jiffies 4294937448 (age 267.270s) hex dump (first 32 bytes): 90 38 8b 01 c0 ff ff ff 00 00 00 00 01 00 00 00 .8.............. 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffc00020f134>] create_object+0x10c/0x2a0 [<ffffffc00070ff44>] kmemleak_alloc+0x54/0xa0 [<ffffffc0001fe378>] __kmalloc+0x1f8/0x4f8 [<ffffffc00028e984>] __register_sysctl_table+0x64/0x5a0 [<ffffffc00028eef0>] register_sysctl+0x30/0x40 [<ffffffc00099c304>] net_sysctl_init+0x20/0x58 [<ffffffc000994dd8>] sock_init+0x10/0xb0 [<ffffffc0000842e0>] do_one_initcall+0x90/0x1b8 [<ffffffc000966bac>] kernel_init_freeable+0x218/0x2f0 [<ffffffc00070ed6c>] kernel_init+0x1c/0xe8 [<ffffffc000083bfc>] ret_from_fork+0xc/0x50 [<ffffffffffffffff>] 0xffffffffffffffff <<end check kmemleak>> Before fix, the objdump result on ARM64: 0000000000000000 <net_sysctl_init>: 0: a9be7bfd stp x29, x30, [sp,#-32]! 4: 90000001 adrp x1, 0 <net_sysctl_init> 8: 90000000 adrp x0, 0 <net_sysctl_init> c: 910003fd mov x29, sp 10: 91000021 add x1, x1, #0x0 14: 91000000 add x0, x0, #0x0 18: a90153f3 stp x19, x20, [sp,#16] 1c: 12800174 mov w20, #0xfffffff4 // #-12 20: 94000000 bl 0 <register_sysctl> 24: b4000120 cbz x0, 48 <net_sysctl_init+0x48> 28: 90000013 adrp x19, 0 <net_sysctl_init> 2c: 91000273 add x19, x19, #0x0 30: 9101a260 add x0, x19, #0x68 34: 94000000 bl 0 <register_pernet_subsys> 38: 2a0003f4 mov w20, w0 3c: 35000060 cbnz w0, 48 <net_sysctl_init+0x48> 40: aa1303e0 mov x0, x19 44: 94000000 bl 0 <register_sysctl_root> 48: 2a1403e0 mov w0, w20 4c: a94153f3 ldp x19, x20, [sp,#16] 50: a8c27bfd ldp x29, x30, [sp],#32 54: d65f03c0 ret After: 0000000000000000 <net_sysctl_init>: 0: a9bd7bfd stp x29, x30, [sp,#-48]! 4: 90000000 adrp x0, 0 <net_sysctl_init> 8: 910003fd mov x29, sp c: a90153f3 stp x19, x20, [sp,#16] 10: 90000013 adrp x19, 0 <net_sysctl_init> 14: 91000000 add x0, x0, #0x0 18: 91000273 add x19, x19, #0x0 1c: f90013f5 str x21, [sp,#32] 20: aa1303e1 mov x1, x19 24: 12800175 mov w21, #0xfffffff4 // #-12 28: 94000000 bl 0 <register_sysctl> 2c: f9002260 str x0, [x19,#64] 30: b40001a0 cbz x0, 64 <net_sysctl_init+0x64> 34: 90000014 adrp x20, 0 <net_sysctl_init> 38: 91000294 add x20, x20, #0x0 3c: 9101a280 add x0, x20, #0x68 40: 94000000 bl 0 <register_pernet_subsys> 44: 2a0003f5 mov w21, w0 48: 35000080 cbnz w0, 58 <net_sysctl_init+0x58> 4c: aa1403e0 mov x0, x20 50: 94000000 bl 0 <register_sysctl_root> 54: 14000004 b 64 <net_sysctl_init+0x64> 58: f9402260 ldr x0, [x19,#64] 5c: 94000000 bl 0 <unregister_sysctl_table> 60: f900227f str xzr, [x19,#64] 64: 2a1503e0 mov w0, w21 68: f94013f5 ldr x21, [sp,#32] 6c: a94153f3 ldp x19, x20, [sp,#16] 70: a8c37bfd ldp x29, x30, [sp],#48 74: d65f03c0 ret Add the possible error handle to free the net_header to remove the kmemleak warning Signed-off-by: Li RongQing <roy.qing.li@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
118 lines
2.9 KiB
C
118 lines
2.9 KiB
C
/* -*- linux-c -*-
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* sysctl_net.c: sysctl interface to net subsystem.
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*
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* Begun April 1, 1996, Mike Shaver.
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* Added /proc/sys/net directories for each protocol family. [MS]
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*
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* Revision 1.2 1996/05/08 20:24:40 shaver
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* Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
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* NET_IPV4_IP_FORWARD.
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*
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*
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*/
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#include <linux/mm.h>
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#include <linux/export.h>
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#include <linux/sysctl.h>
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#include <linux/nsproxy.h>
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#include <net/sock.h>
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#ifdef CONFIG_INET
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#include <net/ip.h>
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#endif
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#ifdef CONFIG_NET
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#include <linux/if_ether.h>
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#endif
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static struct ctl_table_set *
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net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
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{
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return &namespaces->net_ns->sysctls;
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}
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static int is_seen(struct ctl_table_set *set)
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{
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return ¤t->nsproxy->net_ns->sysctls == set;
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}
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/* Return standard mode bits for table entry. */
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static int net_ctl_permissions(struct ctl_table_header *head,
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struct ctl_table *table)
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{
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struct net *net = container_of(head->set, struct net, sysctls);
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kuid_t root_uid = make_kuid(net->user_ns, 0);
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kgid_t root_gid = make_kgid(net->user_ns, 0);
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/* Allow network administrator to have same access as root. */
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if (ns_capable(net->user_ns, CAP_NET_ADMIN) ||
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uid_eq(root_uid, current_euid())) {
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int mode = (table->mode >> 6) & 7;
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return (mode << 6) | (mode << 3) | mode;
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}
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/* Allow netns root group to have the same access as the root group */
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if (in_egroup_p(root_gid)) {
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int mode = (table->mode >> 3) & 7;
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return (mode << 3) | mode;
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}
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return table->mode;
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}
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static struct ctl_table_root net_sysctl_root = {
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.lookup = net_ctl_header_lookup,
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.permissions = net_ctl_permissions,
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};
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static int __net_init sysctl_net_init(struct net *net)
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{
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setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
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return 0;
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}
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static void __net_exit sysctl_net_exit(struct net *net)
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{
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retire_sysctl_set(&net->sysctls);
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}
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static struct pernet_operations sysctl_pernet_ops = {
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.init = sysctl_net_init,
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.exit = sysctl_net_exit,
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};
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static struct ctl_table_header *net_header;
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__init int net_sysctl_init(void)
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{
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static struct ctl_table empty[1];
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int ret = -ENOMEM;
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/* Avoid limitations in the sysctl implementation by
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* registering "/proc/sys/net" as an empty directory not in a
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* network namespace.
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*/
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net_header = register_sysctl("net", empty);
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if (!net_header)
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goto out;
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ret = register_pernet_subsys(&sysctl_pernet_ops);
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if (ret)
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goto out1;
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register_sysctl_root(&net_sysctl_root);
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out:
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return ret;
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out1:
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unregister_sysctl_table(net_header);
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net_header = NULL;
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goto out;
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}
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struct ctl_table_header *register_net_sysctl(struct net *net,
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const char *path, struct ctl_table *table)
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{
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return __register_sysctl_table(&net->sysctls, path, table);
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}
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EXPORT_SYMBOL_GPL(register_net_sysctl);
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void unregister_net_sysctl_table(struct ctl_table_header *header)
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{
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unregister_sysctl_table(header);
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}
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EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);
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