[RFC,v2,18/22] selinux: beef up isvalid checks

Message ID	20241216164055.96267-18-cgoettsche@seltendoof.de (mailing list archive)
State	New
Headers	show Received: from server02.seltendoof.de (server02.seltendoof.de [168.119.48.163]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE4D520B218; Mon, 16 Dec 2024 16:41:59 +0000 (UTC) From: =?utf-8?q?Christian_G=C3=B6ttsche?= <cgoettsche@seltendoof.de> To: selinux@vger.kernel.org Cc: =?utf-8?q?Christian_G=C3=B6ttsche?= <cgzones@googlemail.com>, Paul Moore <paul@paul-moore.com>, Stephen Smalley <stephen.smalley.work@gmail.com>, Ondrej Mosnacek <omosnace@redhat.com>, Nathan Chancellor <nathan@kernel.org>, Nick Desaulniers <ndesaulniers@google.com>, Bill Wendling <morbo@google.com>, Justin Stitt <justinstitt@google.com>, =?utf-8?q?Thi=C3=A9baud_Weksteen?= <tweek@google.com>, =?utf-8?q?Bram_Bonn?= =?utf-8?q?=C3=A9?= <brambonne@google.com>, Masahiro Yamada <masahiroy@kernel.org>, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Casey Schaufler <casey@schaufler-ca.com>, Canfeng Guo <guocanfeng@uniontech.com>, GUO Zihua <guozihua@huawei.com> Subject: [RFC PATCH v2 18/22] selinux: beef up isvalid checks Date: Mon, 16 Dec 2024 17:40:16 +0100 Message-ID: <20241216164055.96267-18-cgoettsche@seltendoof.de> In-Reply-To: <20241216164055.96267-1-cgoettsche@seltendoof.de> References: <20241216164055.96267-1-cgoettsche@seltendoof.de> Reply-To: cgzones@googlemail.com Precedence: bulk MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
Series	[RFC,v2,01/22] selinux: supply missing field initializers \| expand [RFC,v2,01/22] selinux: supply missing field initializers [RFC,v2,02/22] selinux: avoid using types indicating user space interaction [RFC,v2,03/22] selinux: align and constify functions [RFC,v2,04/22] selinux: rework match_ipv6_addrmask() [RFC,v2,05/22] selinux: avoid nontransitive comparison [RFC,v2,06/22] selinux: rename comparison functions for clarity [RFC,v2,07/22] selinux: use known type instead of void pointer [RFC,v2,08/22] selinux: avoid unnecessary indirection in struct level_datum [RFC,v2,09/22] selinux: make use of str_read() [RFC,v2,10/22] selinux: use u16 for security classes [RFC,v2,11/22] selinux: more strict policy parsing [RFC,v2,12/22] selinux: check length fields in policies [RFC,v2,13/22] selinux: validate constraints [RFC,v2,14/22] selinux: pre-validate conditional expressions [RFC,v2,15/22] selinux: introduce ebitmap_highest_set_bit() [RFC,v2,16/22] selinux: check type attr map overflows [RFC,v2,17/22] selinux: reorder policydb_index() [RFC,v2,18/22] selinux: beef up isvalid checks [RFC,v2,19/22] selinux: validate symbols [RFC,v2,20/22] selinux: more strict bounds check [RFC,v2,21/22] selinux: check for simple types [RFC,v2,22/22] selinux: restrict policy strings

diff --git a/security/selinux/ss/hashtab.h b/security/selinux/ss/hashtab.h index deba82d78c3a..c641fb12916b 100644 --- a/security/selinux/ss/hashtab.h +++ b/security/selinux/ss/hashtab.h @@ -94,11 +94,11 @@ static inline int hashtab_insert(struct hashtab *h, void *key, void *datum, * Returns NULL if no entry has the specified key or * the datum of the entry otherwise. */ -static inline void *hashtab_search(struct hashtab *h, const void *key, +static inline void *hashtab_search(const struct hashtab *h, const void *key, struct hashtab_key_params key_params) { u32 hvalue; - struct hashtab_node *cur; + const struct hashtab_node *cur; if (!h->size) return NULL; diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c index a6e49269f535..3cd36e2015fa 100644 --- a/security/selinux/ss/mls.c +++ b/security/selinux/ss/mls.c @@ -32,7 +32,7 @@ int mls_compute_context_len(struct policydb *p, struct context *context) { int i, l, len, head, prev; - char *nm; + const char *nm; struct ebitmap *e; struct ebitmap_node *node; @@ -86,7 +86,8 @@ int mls_compute_context_len(struct policydb *p, struct context *context) void mls_sid_to_context(struct policydb *p, struct context *context, char **scontext) { - char *scontextp, *nm; + const char *nm; + char *scontextp; int i, l, head, prev; struct ebitmap *e; struct ebitmap_node *node; @@ -155,27 +156,44 @@ void mls_sid_to_context(struct policydb *p, struct context *context, *scontext = scontextp; } -int mls_level_isvalid(struct policydb *p, struct mls_level *l) +bool mls_level_isvalid(const struct policydb *p, const struct mls_level *l) { - struct level_datum *levdatum; + const char *name; + const struct level_datum *levdatum; + struct ebitmap_node *node; + u32 bit; + int rc; if (!l->sens || l->sens > p->p_levels.nprim) - return 0; - levdatum = symtab_search(&p->p_levels, - sym_name(p, SYM_LEVELS, l->sens - 1)); + return false; + + name = sym_name(p, SYM_LEVELS, l->sens - 1); + if (!name) + return false; + + levdatum = symtab_search(&p->p_levels, name); if (!levdatum) - return 0; + return false; /* - * Return 1 iff all the bits set in l->cat are also be set in + * Validate that all bits set in l->cat are also be set in * levdatum->level->cat and no bit in l->cat is larger than * p->p_cats.nprim. */ - return ebitmap_contains(&levdatum->level.cat, &l->cat, - p->p_cats.nprim); + rc = ebitmap_contains(&levdatum->level.cat, &l->cat, + p->p_cats.nprim); + if (!rc) + return false; + + ebitmap_for_each_positive_bit(&levdatum->level.cat, node, bit) { + if (!sym_name(p, SYM_CATS, bit)) + return false; + } + + return true; } -int mls_range_isvalid(struct policydb *p, struct mls_range *r) +bool mls_range_isvalid(const struct policydb *p, const struct mls_range *r) { return (mls_level_isvalid(p, &r->level[0]) && mls_level_isvalid(p, &r->level[1]) && @@ -183,32 +201,32 @@ int mls_range_isvalid(struct policydb *p, struct mls_range *r) } /* - * Return 1 if the MLS fields in the security context + * Return true if the MLS fields in the security context * structure `c' are valid. Return 0 otherwise. */ -int mls_context_isvalid(struct policydb *p, struct context *c) +bool mls_context_isvalid(const struct policydb *p, const struct context *c) { - struct user_datum *usrdatum; + const struct user_datum *usrdatum; if (!p->mls_enabled) - return 1; + return true; if (!mls_range_isvalid(p, &c->range)) - return 0; + return false; if (c->role == OBJECT_R_VAL) - return 1; + return true; /* * User must be authorized for the MLS range. */ if (!c->user || c->user > p->p_users.nprim) - return 0; + return false; usrdatum = p->user_val_to_struct[c->user - 1]; - if (!mls_range_contains(usrdatum->range, c->range)) - return 0; /* user may not be associated with range */ + if (!usrdatum || !mls_range_contains(usrdatum->range, c->range)) + return false; /* user may not be associated with range */ - return 1; + return true; } /* @@ -449,8 +467,8 @@ int mls_convert_context(struct policydb *oldp, struct policydb *newp, return 0; for (l = 0; l < 2; l++) { - char *name = sym_name(oldp, SYM_LEVELS, - oldc->range.level[l].sens - 1); + const char *name = sym_name(oldp, SYM_LEVELS, + oldc->range.level[l].sens - 1); levdatum = symtab_search(&newp->p_levels, name); diff --git a/security/selinux/ss/mls.h b/security/selinux/ss/mls.h index 07980636751f..93cde1b22992 100644 --- a/security/selinux/ss/mls.h +++ b/security/selinux/ss/mls.h @@ -27,9 +27,9 @@ int mls_compute_context_len(struct policydb *p, struct context *context); void mls_sid_to_context(struct policydb *p, struct context *context, char **scontext); -int mls_context_isvalid(struct policydb *p, struct context *c); -int mls_range_isvalid(struct policydb *p, struct mls_range *r); -int mls_level_isvalid(struct policydb *p, struct mls_level *l); +bool mls_context_isvalid(const struct policydb *p, const struct context *c); +bool mls_range_isvalid(const struct policydb *p, const struct mls_range *r); +bool mls_level_isvalid(const struct policydb *p, const struct mls_level *l); int mls_context_to_sid(struct policydb *p, char oldc, char *scontext, struct context *context, struct sidtab *s, u32 def_sid); diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index 348cbe36502e..a4c9377b8060 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -923,51 +923,59 @@ int policydb_load_isids(struct policydb *p, struct sidtab *s) return 0; } -int policydb_class_isvalid(struct policydb *p, u16 class) +bool policydb_class_isvalid(const struct policydb *p, u16 class) { if (!class || class > p->p_classes.nprim) - return 0; - return 1; + return false; + if (!p->sym_val_to_name[SYM_CLASSES][class - 1]) + return false; + return true; } -int policydb_role_isvalid(struct policydb *p, unsigned int role) +bool policydb_role_isvalid(const struct policydb *p, u32 role) { if (!role || role > p->p_roles.nprim) - return 0; - return 1; + return false; + if (!p->sym_val_to_name[SYM_ROLES][role - 1]) + return false; + return true; } -int policydb_type_isvalid(struct policydb *p, unsigned int type) +bool policydb_type_isvalid(const struct policydb *p, u32 type) { if (!type || type > p->p_types.nprim) - return 0; - return 1; + return false; + if (!p->sym_val_to_name[SYM_TYPES][type - 1]) + return false; + return true; } -int policydb_boolean_isvalid(const struct policydb *p, u32 boolean) +bool policydb_boolean_isvalid(const struct policydb *p, u32 boolean) { if (!boolean || boolean > p->p_bools.nprim) - return 0; - return 1; + return false; + if (!p->sym_val_to_name[SYM_BOOLS][boolean - 1]) + return false; + return true; } /* - * Return 1 if the fields in the security context + * Return true if the fields in the security context * structure `c' are valid. Return 0 otherwise. */ -int policydb_context_isvalid(struct policydb *p, struct context *c) +bool policydb_context_isvalid(const struct policydb *p, const struct context *c) { - struct role_datum *role; - struct user_datum *usrdatum; + const struct role_datum *role; + const struct user_datum *usrdatum; if (!c->role || c->role > p->p_roles.nprim) - return 0; + return false; if (!c->user || c->user > p->p_users.nprim) - return 0; + return false; if (!c->type || c->type > p->p_types.nprim) - return 0; + return false; if (c->role != OBJECT_R_VAL) { /* @@ -976,24 +984,24 @@ int policydb_context_isvalid(struct policydb *p, struct context *c) role = p->role_val_to_struct[c->role - 1]; if (!role || !ebitmap_get_bit(&role->types, c->type - 1)) /* role may not be associated with type */ - return 0; + return false; /* * User must be authorized for the role. */ usrdatum = p->user_val_to_struct[c->user - 1]; if (!usrdatum) - return 0; + return false; if (!ebitmap_get_bit(&usrdatum->roles, c->role - 1)) /* user may not be associated with role */ - return 0; + return false; } if (!mls_context_isvalid(p, c)) - return 0; + return false; - return 1; + return true; } /* diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h index 615fdd5ef3c3..aa3b21bd5286 100644 --- a/security/selinux/ss/policydb.h +++ b/security/selinux/ss/policydb.h @@ -319,11 +319,11 @@ struct policy_file { extern void policydb_destroy(struct policydb *p); extern int policydb_load_isids(struct policydb *p, struct sidtab *s); -extern int policydb_context_isvalid(struct policydb *p, struct context *c); -extern int policydb_class_isvalid(struct policydb *p, u16 class); -extern int policydb_type_isvalid(struct policydb *p, unsigned int type); -extern int policydb_role_isvalid(struct policydb *p, unsigned int role); -extern int policydb_boolean_isvalid(const struct policydb *p, u32 boolean); +extern bool policydb_context_isvalid(const struct policydb *p, const struct context *c); +extern bool policydb_class_isvalid(const struct policydb *p, u16 class); +extern bool policydb_type_isvalid(const struct policydb *p, u32 type); +extern bool policydb_role_isvalid(const struct policydb *p, u32 role); +extern bool policydb_boolean_isvalid(const struct policydb *p, u32 boolean); extern int policydb_read(struct policydb *p, struct policy_file *fp); extern int policydb_write(struct policydb *p, struct policy_file *fp); @@ -394,7 +394,7 @@ static inline int put_entry(const void *buf, size_t bytes, size_t num, return 0; } -static inline char *sym_name(struct policydb *p, unsigned int sym_num, +static inline const char *sym_name(const struct policydb *p, unsigned int sym_num, unsigned int element_nr) { return p->sym_val_to_name[sym_num][element_nr]; diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 797b9a0692fd..227fe7832c08 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -463,7 +463,7 @@ static void security_dump_masked_av(struct policydb *policydb, struct common_datum *common_dat; struct class_datum *tclass_dat; struct audit_buffer *ab; - char *tclass_name; + const char *tclass_name; char *scontext_name = NULL; char *tcontext_name = NULL; char *permission_names[32]; diff --git a/security/selinux/ss/symtab.c b/security/selinux/ss/symtab.c index 832660fd84a9..a756554e7f1d 100644 --- a/security/selinux/ss/symtab.c +++ b/security/selinux/ss/symtab.c @@ -50,7 +50,7 @@ int symtab_insert(struct symtab *s, char *name, void *datum) return hashtab_insert(&s->table, name, datum, symtab_key_params); } -void *symtab_search(struct symtab *s, const char *name) +void *symtab_search(const struct symtab *s, const char *name) { return hashtab_search(&s->table, name, symtab_key_params); } diff --git a/security/selinux/ss/symtab.h b/security/selinux/ss/symtab.h index 8e667cdbf38f..7cfa3b44953a 100644 --- a/security/selinux/ss/symtab.h +++ b/security/selinux/ss/symtab.h @@ -21,6 +21,6 @@ struct symtab { int symtab_init(struct symtab *s, u32 size); int symtab_insert(struct symtab *s, char *name, void *datum); -void *symtab_search(struct symtab *s, const char *name); +void *symtab_search(const struct symtab *s, const char *name); #endif /* _SS_SYMTAB_H_ */

[RFC,v2,18/22] selinux: beef up isvalid checks

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