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[xen stable-4.14] tools/xenstore: introduce node_perms structure

Date: Wed, 16 Dec 2020 06:01:23 +0000

Delivery-date: Wed, 16 Dec 2020 06:01:25 +0000

List-id: "Change log for Mercurial \(receive only\)" <xen-changelog.lists.xenproject.org>

commit 52593586d58086fe27cfbed3dc9beeae3d9c8c09 Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Thu Jun 11 16:12:44 2020 +0200 Commit: Jan Beulich <jbeulich@xxxxxxxx> CommitDate: Tue Dec 15 14:06:12 2020 +0100 tools/xenstore: introduce node_perms structure There are several places in xenstored using a permission array and the size of that array. Introduce a new struct node_perms containing both. This is part of XSA-115. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Acked-by: Julien Grall <jgrall@xxxxxxxxxx> Reviewed-by: Paul Durrant <paul@xxxxxxx> --- tools/xenstore/xenstored_core.c | 79 +++++++++++++++++++-------------------- tools/xenstore/xenstored_core.h | 8 +++- tools/xenstore/xenstored_domain.c | 12 +++--- 3 files changed, 50 insertions(+), 49 deletions(-) diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c index 20a7a35815..79d305fbbe 100644 --- a/tools/xenstore/xenstored_core.c +++ b/tools/xenstore/xenstored_core.c @@ -403,14 +403,14 @@ static struct node *read_node(struct connection *conn, const void *ctx, /* Datalen, childlen, number of permissions */ hdr = (void *)data.dptr; node->generation = hdr->generation; - node->num_perms = hdr->num_perms; + node->perms.num = hdr->num_perms; node->datalen = hdr->datalen; node->childlen = hdr->childlen; /* Permissions are struct xs_permissions. */ - node->perms = hdr->perms; + node->perms.p = hdr->perms; /* Data is binary blob (usually ascii, no nul). */ - node->data = node->perms + node->num_perms; + node->data = node->perms.p + node->perms.num; /* Children is strings, nul separated. */ node->children = node->data + node->datalen; @@ -427,7 +427,7 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, struct xs_tdb_record_hdr *hdr; data.dsize = sizeof(*hdr) - + node->num_perms*sizeof(node->perms[0]) + + node->perms.num * sizeof(node->perms.p[0]) + node->datalen + node->childlen; if (!no_quota_check && domain_is_unprivileged(conn) && @@ -439,12 +439,13 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, data.dptr = talloc_size(node, data.dsize); hdr = (void *)data.dptr; hdr->generation = node->generation; - hdr->num_perms = node->num_perms; + hdr->num_perms = node->perms.num; hdr->datalen = node->datalen; hdr->childlen = node->childlen; - memcpy(hdr->perms, node->perms, node->num_perms*sizeof(node->perms[0])); - p = hdr->perms + node->num_perms; + memcpy(hdr->perms, node->perms.p, + node->perms.num * sizeof(*node->perms.p)); + p = hdr->perms + node->perms.num; memcpy(p, node->data, node->datalen); p += node->datalen; memcpy(p, node->children, node->childlen); @@ -470,8 +471,7 @@ static int write_node(struct connection *conn, struct node *node, } static enum xs_perm_type perm_for_conn(struct connection *conn, - struct xs_permissions *perms, - unsigned int num) + const struct node_perms *perms) { unsigned int i; enum xs_perm_type mask = XS_PERM_READ|XS_PERM_WRITE|XS_PERM_OWNER; @@ -480,16 +480,16 @@ static enum xs_perm_type perm_for_conn(struct connection *conn, mask &= ~XS_PERM_WRITE; /* Owners and tools get it all... */ - if (!domain_is_unprivileged(conn) || perms[0].id == conn->id - || (conn->target && perms[0].id == conn->target->id)) + if (!domain_is_unprivileged(conn) || perms->p[0].id == conn->id + || (conn->target && perms->p[0].id == conn->target->id)) return (XS_PERM_READ|XS_PERM_WRITE|XS_PERM_OWNER) & mask; - for (i = 1; i < num; i++) - if (perms[i].id == conn->id - || (conn->target && perms[i].id == conn->target->id)) - return perms[i].perms & mask; + for (i = 1; i < perms->num; i++) + if (perms->p[i].id == conn->id + || (conn->target && perms->p[i].id == conn->target->id)) + return perms->p[i].perms & mask; - return perms[0].perms & mask; + return perms->p[0].perms & mask; } /* @@ -536,7 +536,7 @@ static int ask_parents(struct connection *conn, const void *ctx, return 0; } - *perm = perm_for_conn(conn, node->perms, node->num_perms); + *perm = perm_for_conn(conn, &node->perms); return 0; } @@ -582,8 +582,7 @@ struct node *get_node(struct connection *conn, node = read_node(conn, ctx, name); /* If we don't have permission, we don't have node. */ if (node) { - if ((perm_for_conn(conn, node->perms, node->num_perms) & perm) - != perm) { + if ((perm_for_conn(conn, &node->perms) & perm) != perm) { errno = EACCES; node = NULL; } @@ -759,16 +758,15 @@ const char *onearg(struct buffered_data *in) return in->buffer; } -static char *perms_to_strings(const void *ctx, - struct xs_permissions *perms, unsigned int num, +static char *perms_to_strings(const void *ctx, const struct node_perms *perms, unsigned int *len) { unsigned int i; char *strings = NULL; char buffer[MAX_STRLEN(unsigned int) + 1]; - for (*len = 0, i = 0; i < num; i++) { - if (!xs_perm_to_string(&perms[i], buffer, sizeof(buffer))) + for (*len = 0, i = 0; i < perms->num; i++) { + if (!xs_perm_to_string(&perms->p[i], buffer, sizeof(buffer))) return NULL; strings = talloc_realloc(ctx, strings, char, @@ -947,13 +945,13 @@ static struct node *construct_node(struct connection *conn, const void *ctx, goto nomem; /* Inherit permissions, except unprivileged domains own what they create */ - node->num_perms = parent->num_perms; - node->perms = talloc_memdup(node, parent->perms, - node->num_perms * sizeof(node->perms[0])); - if (!node->perms) + node->perms.num = parent->perms.num; + node->perms.p = talloc_memdup(node, parent->perms.p, + node->perms.num * sizeof(*node->perms.p)); + if (!node->perms.p) goto nomem; if (domain_is_unprivileged(conn)) - node->perms[0].id = conn->id; + node->perms.p[0].id = conn->id; /* No children, no data */ node->children = node->data = NULL; @@ -1230,7 +1228,7 @@ static int do_get_perms(struct connection *conn, struct buffered_data *in) if (!node) return errno; - strings = perms_to_strings(node, node->perms, node->num_perms, &len); + strings = perms_to_strings(node, &node->perms, &len); if (!strings) return errno; @@ -1241,13 +1239,12 @@ static int do_get_perms(struct connection *conn, struct buffered_data *in) static int do_set_perms(struct connection *conn, struct buffered_data *in) { - unsigned int num; - struct xs_permissions *perms; + struct node_perms perms; char *name, *permstr; struct node *node; - num = xs_count_strings(in->buffer, in->used); - if (num < 2) + perms.num = xs_count_strings(in->buffer, in->used); + if (perms.num < 2) return EINVAL; /* First arg is node name. */ @@ -1258,21 +1255,21 @@ static int do_set_perms(struct connection *conn, struct buffered_data *in) return errno; permstr = in->buffer + strlen(in->buffer) + 1; - num--; + perms.num--; - perms = talloc_array(node, struct xs_permissions, num); - if (!perms) + perms.p = talloc_array(node, struct xs_permissions, perms.num); + if (!perms.p) return ENOMEM; - if (!xs_strings_to_perms(perms, num, permstr)) + if (!xs_strings_to_perms(perms.p, perms.num, permstr)) return errno; /* Unprivileged domains may not change the owner. */ - if (domain_is_unprivileged(conn) && perms[0].id != node->perms[0].id) + if (domain_is_unprivileged(conn) && + perms.p[0].id != node->perms.p[0].id) return EPERM; domain_entry_dec(conn, node); node->perms = perms; - node->num_perms = num; domain_entry_inc(conn, node); if (write_node(conn, node, false)) @@ -1547,8 +1544,8 @@ static void manual_node(const char *name, const char *child) barf_perror("Could not allocate initial node %s", name); node->name = name; - node->perms = &perms; - node->num_perms = 1; + node->perms.p = &perms; + node->perms.num = 1; node->children = (char *)child; if (child) node->childlen = strlen(child) + 1; diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h index 29d638fbc5..47ba0916db 100644 --- a/tools/xenstore/xenstored_core.h +++ b/tools/xenstore/xenstored_core.h @@ -109,6 +109,11 @@ struct connection }; extern struct list_head connections; +struct node_perms { + unsigned int num; + struct xs_permissions *p; +}; + struct node { const char *name; @@ -120,8 +125,7 @@ struct node { #define NO_GENERATION ~((uint64_t)0) /* Permissions. */ - unsigned int num_perms; - struct xs_permissions *perms; + struct node_perms perms; /* Contents. */ unsigned int datalen; diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c index 2d0d87ee89..aa9942fcc2 100644 --- a/tools/xenstore/xenstored_domain.c +++ b/tools/xenstore/xenstored_domain.c @@ -650,12 +650,12 @@ void domain_entry_inc(struct connection *conn, struct node *node) if (!conn) return; - if (node->perms && node->perms[0].id != conn->id) { + if (node->perms.p && node->perms.p[0].id != conn->id) { if (conn->transaction) { transaction_entry_inc(conn->transaction, - node->perms[0].id); + node->perms.p[0].id); } else { - d = find_domain_by_domid(node->perms[0].id); + d = find_domain_by_domid(node->perms.p[0].id); if (d) d->nbentry++; } @@ -676,12 +676,12 @@ void domain_entry_dec(struct connection *conn, struct node *node) if (!conn) return; - if (node->perms && node->perms[0].id != conn->id) { + if (node->perms.p && node->perms.p[0].id != conn->id) { if (conn->transaction) { transaction_entry_dec(conn->transaction, - node->perms[0].id); + node->perms.p[0].id); } else { - d = find_domain_by_domid(node->perms[0].id); + d = find_domain_by_domid(node->perms.p[0].id); if (d && d->nbentry) d->nbentry--; } -- generated by git-patchbot for /home/xen/git/xen.git#stable-4.14

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