From 8665bd53f2f2e27e5511d90428cb3f60e6d0ce15 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 20:50:12 +0200 Subject: Merging upstream version 6.8.9. Signed-off-by: Daniel Baumann --- fs/afs/addr_prefs.c | 531 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 531 insertions(+) create mode 100644 fs/afs/addr_prefs.c (limited to 'fs/afs/addr_prefs.c') diff --git a/fs/afs/addr_prefs.c b/fs/afs/addr_prefs.c new file mode 100644 index 0000000000..a189ff8a50 --- /dev/null +++ b/fs/afs/addr_prefs.c @@ -0,0 +1,531 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Address preferences management + * + * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": addr_prefs: " fmt +#include +#include +#include +#include +#include +#include "internal.h" + +static inline struct afs_net *afs_seq2net_single(struct seq_file *m) +{ + return afs_net(seq_file_single_net(m)); +} + +/* + * Split a NUL-terminated string up to the first newline around spaces. The + * source string will be modified to have NUL-terminations inserted. + */ +static int afs_split_string(char **pbuf, char *strv[], unsigned int maxstrv) +{ + unsigned int count = 0; + char *p = *pbuf; + + maxstrv--; /* Allow for terminal NULL */ + for (;;) { + /* Skip over spaces */ + while (isspace(*p)) { + if (*p == '\n') { + p++; + break; + } + p++; + } + if (!*p) + break; + + /* Mark start of word */ + if (count >= maxstrv) { + pr_warn("Too many elements in string\n"); + return -EINVAL; + } + strv[count++] = p; + + /* Skip over word */ + while (!isspace(*p)) + p++; + if (!*p) + break; + + /* Mark end of word */ + if (*p == '\n') { + *p++ = 0; + break; + } + *p++ = 0; + } + + *pbuf = p; + strv[count] = NULL; + return count; +} + +/* + * Parse an address with an optional subnet mask. + */ +static int afs_parse_address(char *p, struct afs_addr_preference *pref) +{ + const char *stop; + unsigned long mask, tmp; + char *end = p + strlen(p); + bool bracket = false; + + if (*p == '[') { + p++; + bracket = true; + } + +#if 0 + if (*p == '[') { + p++; + q = memchr(p, ']', end - p); + if (!q) { + pr_warn("Can't find closing ']'\n"); + return -EINVAL; + } + } else { + for (q = p; q < end; q++) + if (*q == '/') + break; + } +#endif + + if (in4_pton(p, end - p, (u8 *)&pref->ipv4_addr, -1, &stop)) { + pref->family = AF_INET; + mask = 32; + } else if (in6_pton(p, end - p, (u8 *)&pref->ipv6_addr, -1, &stop)) { + pref->family = AF_INET6; + mask = 128; + } else { + pr_warn("Can't determine address family\n"); + return -EINVAL; + } + + p = (char *)stop; + if (bracket) { + if (*p != ']') { + pr_warn("Can't find closing ']'\n"); + return -EINVAL; + } + p++; + } + + if (*p == '/') { + p++; + tmp = simple_strtoul(p, &p, 10); + if (tmp > mask) { + pr_warn("Subnet mask too large\n"); + return -EINVAL; + } + if (tmp == 0) { + pr_warn("Subnet mask too small\n"); + return -EINVAL; + } + mask = tmp; + } + + if (*p) { + pr_warn("Invalid address\n"); + return -EINVAL; + } + + pref->subnet_mask = mask; + return 0; +} + +enum cmp_ret { + CONTINUE_SEARCH, + INSERT_HERE, + EXACT_MATCH, + SUBNET_MATCH, +}; + +/* + * See if a candidate address matches a listed address. + */ +static enum cmp_ret afs_cmp_address_pref(const struct afs_addr_preference *a, + const struct afs_addr_preference *b) +{ + int subnet = min(a->subnet_mask, b->subnet_mask); + const __be32 *pa, *pb; + u32 mask, na, nb; + int diff; + + if (a->family != b->family) + return INSERT_HERE; + + switch (a->family) { + case AF_INET6: + pa = a->ipv6_addr.s6_addr32; + pb = b->ipv6_addr.s6_addr32; + break; + case AF_INET: + pa = &a->ipv4_addr.s_addr; + pb = &b->ipv4_addr.s_addr; + break; + } + + while (subnet > 32) { + diff = ntohl(*pa++) - ntohl(*pb++); + if (diff < 0) + return INSERT_HERE; /* a 0) + return CONTINUE_SEARCH; /* a>b */ + subnet -= 32; + } + + if (subnet == 0) + return EXACT_MATCH; + + mask = 0xffffffffU << (32 - subnet); + na = ntohl(*pa); + nb = ntohl(*pb); + diff = (na & mask) - (nb & mask); + //kdebug("diff %08x %08x %08x %d", na, nb, mask, diff); + if (diff < 0) + return INSERT_HERE; /* a 0) + return CONTINUE_SEARCH; /* a>b */ + if (a->subnet_mask == b->subnet_mask) + return EXACT_MATCH; + if (a->subnet_mask > b->subnet_mask) + return SUBNET_MATCH; /* a binds tighter than b */ + return CONTINUE_SEARCH; /* b binds tighter than a */ +} + +/* + * Insert an address preference. + */ +static int afs_insert_address_pref(struct afs_addr_preference_list **_preflist, + struct afs_addr_preference *pref, + int index) +{ + struct afs_addr_preference_list *preflist = *_preflist, *old = preflist; + size_t size, max_prefs; + + _enter("{%u/%u/%u},%u", preflist->ipv6_off, preflist->nr, preflist->max_prefs, index); + + if (preflist->nr == 255) + return -ENOSPC; + if (preflist->nr >= preflist->max_prefs) { + max_prefs = preflist->max_prefs + 1; + size = struct_size(preflist, prefs, max_prefs); + size = roundup_pow_of_two(size); + max_prefs = min_t(size_t, (size - sizeof(*preflist)) / sizeof(*pref), 255); + preflist = kmalloc(size, GFP_KERNEL); + if (!preflist) + return -ENOMEM; + *preflist = **_preflist; + preflist->max_prefs = max_prefs; + *_preflist = preflist; + + if (index < preflist->nr) + memcpy(preflist->prefs + index + 1, old->prefs + index, + sizeof(*pref) * (preflist->nr - index)); + if (index > 0) + memcpy(preflist->prefs, old->prefs, sizeof(*pref) * index); + } else { + if (index < preflist->nr) + memmove(preflist->prefs + index + 1, preflist->prefs + index, + sizeof(*pref) * (preflist->nr - index)); + } + + preflist->prefs[index] = *pref; + preflist->nr++; + if (pref->family == AF_INET) + preflist->ipv6_off++; + return 0; +} + +/* + * Add an address preference. + * echo "add [/] " >/proc/fs/afs/addr_prefs + */ +static int afs_add_address_pref(struct afs_net *net, struct afs_addr_preference_list **_preflist, + int argc, char **argv) +{ + struct afs_addr_preference_list *preflist = *_preflist; + struct afs_addr_preference pref; + enum cmp_ret cmp; + int ret, i, stop; + + if (argc != 3) { + pr_warn("Wrong number of params\n"); + return -EINVAL; + } + + if (strcmp(argv[0], "udp") != 0) { + pr_warn("Unsupported protocol\n"); + return -EINVAL; + } + + ret = afs_parse_address(argv[1], &pref); + if (ret < 0) + return ret; + + ret = kstrtou16(argv[2], 10, &pref.prio); + if (ret < 0) { + pr_warn("Invalid priority\n"); + return ret; + } + + if (pref.family == AF_INET) { + i = 0; + stop = preflist->ipv6_off; + } else { + i = preflist->ipv6_off; + stop = preflist->nr; + } + + for (; i < stop; i++) { + cmp = afs_cmp_address_pref(&pref, &preflist->prefs[i]); + switch (cmp) { + case CONTINUE_SEARCH: + continue; + case INSERT_HERE: + case SUBNET_MATCH: + return afs_insert_address_pref(_preflist, &pref, i); + case EXACT_MATCH: + preflist->prefs[i].prio = pref.prio; + return 0; + } + } + + return afs_insert_address_pref(_preflist, &pref, i); +} + +/* + * Delete an address preference. + */ +static int afs_delete_address_pref(struct afs_addr_preference_list **_preflist, + int index) +{ + struct afs_addr_preference_list *preflist = *_preflist; + + _enter("{%u/%u/%u},%u", preflist->ipv6_off, preflist->nr, preflist->max_prefs, index); + + if (preflist->nr == 0) + return -ENOENT; + + if (index < preflist->nr - 1) + memmove(preflist->prefs + index, preflist->prefs + index + 1, + sizeof(preflist->prefs[0]) * (preflist->nr - index - 1)); + + if (index < preflist->ipv6_off) + preflist->ipv6_off--; + preflist->nr--; + return 0; +} + +/* + * Delete an address preference. + * echo "del [/]" >/proc/fs/afs/addr_prefs + */ +static int afs_del_address_pref(struct afs_net *net, struct afs_addr_preference_list **_preflist, + int argc, char **argv) +{ + struct afs_addr_preference_list *preflist = *_preflist; + struct afs_addr_preference pref; + enum cmp_ret cmp; + int ret, i, stop; + + if (argc != 2) { + pr_warn("Wrong number of params\n"); + return -EINVAL; + } + + if (strcmp(argv[0], "udp") != 0) { + pr_warn("Unsupported protocol\n"); + return -EINVAL; + } + + ret = afs_parse_address(argv[1], &pref); + if (ret < 0) + return ret; + + if (pref.family == AF_INET) { + i = 0; + stop = preflist->ipv6_off; + } else { + i = preflist->ipv6_off; + stop = preflist->nr; + } + + for (; i < stop; i++) { + cmp = afs_cmp_address_pref(&pref, &preflist->prefs[i]); + switch (cmp) { + case CONTINUE_SEARCH: + continue; + case INSERT_HERE: + case SUBNET_MATCH: + return 0; + case EXACT_MATCH: + return afs_delete_address_pref(_preflist, i); + } + } + + return -ENOANO; +} + +/* + * Handle writes to /proc/fs/afs/addr_prefs + */ +int afs_proc_addr_prefs_write(struct file *file, char *buf, size_t size) +{ + struct afs_addr_preference_list *preflist, *old; + struct seq_file *m = file->private_data; + struct afs_net *net = afs_seq2net_single(m); + size_t psize; + char *argv[5]; + int ret, argc, max_prefs; + + inode_lock(file_inode(file)); + + /* Allocate a candidate new list and initialise it from the old. */ + old = rcu_dereference_protected(net->address_prefs, + lockdep_is_held(&file_inode(file)->i_rwsem)); + + if (old) + max_prefs = old->nr + 1; + else + max_prefs = 1; + + psize = struct_size(old, prefs, max_prefs); + psize = roundup_pow_of_two(psize); + max_prefs = min_t(size_t, (psize - sizeof(*old)) / sizeof(old->prefs[0]), 255); + + ret = -ENOMEM; + preflist = kmalloc(struct_size(preflist, prefs, max_prefs), GFP_KERNEL); + if (!preflist) + goto done; + + if (old) + memcpy(preflist, old, struct_size(preflist, prefs, old->nr)); + else + memset(preflist, 0, sizeof(*preflist)); + preflist->max_prefs = max_prefs; + + do { + argc = afs_split_string(&buf, argv, ARRAY_SIZE(argv)); + if (argc < 0) + return argc; + if (argc < 2) + goto inval; + + if (strcmp(argv[0], "add") == 0) + ret = afs_add_address_pref(net, &preflist, argc - 1, argv + 1); + else if (strcmp(argv[0], "del") == 0) + ret = afs_del_address_pref(net, &preflist, argc - 1, argv + 1); + else + goto inval; + if (ret < 0) + goto done; + } while (*buf); + + preflist->version++; + rcu_assign_pointer(net->address_prefs, preflist); + /* Store prefs before version */ + smp_store_release(&net->address_pref_version, preflist->version); + kfree_rcu(old, rcu); + preflist = NULL; + ret = 0; + +done: + kfree(preflist); + inode_unlock(file_inode(file)); + _leave(" = %d", ret); + return ret; + +inval: + pr_warn("Invalid Command\n"); + ret = -EINVAL; + goto done; +} + +/* + * Mark the priorities on an address list if the address preferences table has + * changed. The caller must hold the RCU read lock. + */ +void afs_get_address_preferences_rcu(struct afs_net *net, struct afs_addr_list *alist) +{ + const struct afs_addr_preference_list *preflist = + rcu_dereference(net->address_prefs); + const struct sockaddr_in6 *sin6; + const struct sockaddr_in *sin; + const struct sockaddr *sa; + struct afs_addr_preference test; + enum cmp_ret cmp; + int i, j; + + if (!preflist || !preflist->nr || !alist->nr_addrs || + smp_load_acquire(&alist->addr_pref_version) == preflist->version) + return; + + test.family = AF_INET; + test.subnet_mask = 32; + test.prio = 0; + for (i = 0; i < alist->nr_ipv4; i++) { + sa = rxrpc_kernel_remote_addr(alist->addrs[i].peer); + sin = (const struct sockaddr_in *)sa; + test.ipv4_addr = sin->sin_addr; + for (j = 0; j < preflist->ipv6_off; j++) { + cmp = afs_cmp_address_pref(&test, &preflist->prefs[j]); + switch (cmp) { + case CONTINUE_SEARCH: + continue; + case INSERT_HERE: + break; + case EXACT_MATCH: + case SUBNET_MATCH: + WRITE_ONCE(alist->addrs[i].prio, preflist->prefs[j].prio); + break; + } + } + } + + test.family = AF_INET6; + test.subnet_mask = 128; + test.prio = 0; + for (; i < alist->nr_addrs; i++) { + sa = rxrpc_kernel_remote_addr(alist->addrs[i].peer); + sin6 = (const struct sockaddr_in6 *)sa; + test.ipv6_addr = sin6->sin6_addr; + for (j = preflist->ipv6_off; j < preflist->nr; j++) { + cmp = afs_cmp_address_pref(&test, &preflist->prefs[j]); + switch (cmp) { + case CONTINUE_SEARCH: + continue; + case INSERT_HERE: + break; + case EXACT_MATCH: + case SUBNET_MATCH: + WRITE_ONCE(alist->addrs[i].prio, preflist->prefs[j].prio); + break; + } + } + } + + smp_store_release(&alist->addr_pref_version, preflist->version); +} + +/* + * Mark the priorities on an address list if the address preferences table has + * changed. Avoid taking the RCU read lock if we can. + */ +void afs_get_address_preferences(struct afs_net *net, struct afs_addr_list *alist) +{ + if (!net->address_prefs || + /* Load version before prefs */ + smp_load_acquire(&net->address_pref_version) == alist->addr_pref_version) + return; + + rcu_read_lock(); + afs_get_address_preferences_rcu(net, alist); + rcu_read_unlock(); +} -- cgit v1.2.3