diff --git a/libsepol/include/sepol/policydb/policydb.h b/libsepol/include/sepol/policydb/policydb.h index c27275e..0165eed 100644 --- a/libsepol/include/sepol/policydb/policydb.h +++ b/libsepol/include/sepol/policydb/policydb.h @@ -683,10 +683,11 @@ extern int policydb_set_target_platform(policydb_t *p, int platform); #define POLICYDB_VERSION_ROLETRANS 26 #define POLICYDB_VERSION_NEW_OBJECT_DEFAULTS 27 #define POLICYDB_VERSION_DEFAULT_TYPE 28 +#define POLICYDB_VERSION_CONSTRAINT_NAMES 29 /* Range of policy versions we understand*/ #define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE -#define POLICYDB_VERSION_MAX POLICYDB_VERSION_DEFAULT_TYPE +#define POLICYDB_VERSION_MAX POLICYDB_VERSION_CONSTRAINT_NAMES /* Module versions and specific changes*/ #define MOD_POLICYDB_VERSION_BASE 4 @@ -704,9 +705,10 @@ extern int policydb_set_target_platform(policydb_t *p, int platform); #define MOD_POLICYDB_VERSION_TUNABLE_SEP 14 #define MOD_POLICYDB_VERSION_NEW_OBJECT_DEFAULTS 15 #define MOD_POLICYDB_VERSION_DEFAULT_TYPE 16 +#define MOD_POLICYDB_VERSION_CONSTRAINT_NAMES 17 #define MOD_POLICYDB_VERSION_MIN MOD_POLICYDB_VERSION_BASE -#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_DEFAULT_TYPE +#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_CONSTRAINT_NAMES #define POLICYDB_CONFIG_MLS 1 diff --git a/libsepol/include/sepol/policydb/services.h b/libsepol/include/sepol/policydb/services.h index aef0c7b..1969a10 100644 --- a/libsepol/include/sepol/policydb/services.h +++ b/libsepol/include/sepol/policydb/services.h @@ -58,6 +58,38 @@ extern int sepol_compute_av_reason(sepol_security_id_t ssid, struct sepol_av_decision *avd, unsigned int *reason); +/* + * Same as above, but also returns the constraint expression calculations + * whether allowed or denied in a buffer. This buffer is allocated by + * this call and must be free'd by the caller using free(3). The contraint + * buffer will contain any constraints in infix notation. + * If the SHOW_GRANTED flag is set it will show granted and denied + * constraints. The default is to show only denied constraints. + */ +#define SHOW_GRANTED 1 +extern int sepol_compute_av_reason_buffer(sepol_security_id_t ssid, + sepol_security_id_t tsid, + sepol_security_class_t tclass, + sepol_access_vector_t requested, + struct sepol_av_decision *avd, + unsigned int *reason, + char **reason_buf, + unsigned int flags); +/* + * Return a class ID associated with the class string representation + * specified by `class_name'. + */ +extern int sepol_class_name_to_id(const char *class_name, + sepol_security_class_t *tclass); + +/* + * Return a permission av bit associated with tclass and the string + * representation of the `perm_name'. + */ +extern int sepol_perm_name_to_av(sepol_security_class_t tclass, + const char *perm_name, + sepol_access_vector_t *av); + /* * Compute a SID to use for labeling a new object in the * class `tclass' based on a SID pair. diff --git a/libsepol/src/expand.c b/libsepol/src/expand.c index f0555bb..6fd992f 100644 --- a/libsepol/src/expand.c +++ b/libsepol/src/expand.c @@ -384,6 +384,17 @@ static int constraint_node_clone(constraint_node_t ** dst, new_expr->op = expr->op; if (new_expr->expr_type == CEXPR_NAMES) { if (new_expr->attr & CEXPR_TYPE) { + /* + * Copy over constraint policy source types and/or + * attributes for sepol_compute_av_reason_buffer(3) so that + * utilities can analyse constraint errors. + */ + if (map_ebitmap(&expr->type_names->types, + &new_expr->type_names->types, + state->typemap)) { + ERR(NULL, "Failed to map type_names->types"); + goto out_of_mem; + } /* Type sets require expansion and conversion. */ if (expand_convert_type_set(state->out, state-> diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c index 1f49261..8c7efbc 100644 --- a/libsepol/src/policydb.c +++ b/libsepol/src/policydb.c @@ -165,6 +165,13 @@ static struct policydb_compat_info policydb_compat[] = { .target_platform = SEPOL_TARGET_SELINUX, }, { + .type = POLICY_KERN, + .version = POLICYDB_VERSION_CONSTRAINT_NAMES, + .sym_num = SYM_NUM, + .ocon_num = OCON_NODE6 + 1, + .target_platform = SEPOL_TARGET_SELINUX, + }, + { .type = POLICY_BASE, .version = MOD_POLICYDB_VERSION_BASE, .sym_num = SYM_NUM, @@ -256,6 +263,13 @@ static struct policydb_compat_info policydb_compat[] = { .target_platform = SEPOL_TARGET_SELINUX, }, { + .type = POLICY_BASE, + .version = MOD_POLICYDB_VERSION_CONSTRAINT_NAMES, + .sym_num = SYM_NUM, + .ocon_num = OCON_NODE6 + 1, + .target_platform = SEPOL_TARGET_SELINUX, + }, + { .type = POLICY_MOD, .version = MOD_POLICYDB_VERSION_BASE, .sym_num = SYM_NUM, @@ -346,6 +360,13 @@ static struct policydb_compat_info policydb_compat[] = { .ocon_num = 0, .target_platform = SEPOL_TARGET_SELINUX, }, + { + .type = POLICY_MOD, + .version = MOD_POLICYDB_VERSION_CONSTRAINT_NAMES, + .sym_num = SYM_NUM, + .ocon_num = 0, + .target_platform = SEPOL_TARGET_SELINUX, + }, }; #if 0 @@ -2019,6 +2040,10 @@ static int read_cons_helper(policydb_t * p, constraint_node_t ** nodep, if (p->policy_type != POLICY_KERN && type_set_read(e->type_names, fp)) return -1; + else if (p->policy_type == POLICY_KERN && + p->policyvers >= POLICYDB_VERSION_CONSTRAINT_NAMES && + type_set_read(e->type_names, fp)) + return -1; break; default: return -1; diff --git a/libsepol/src/services.c b/libsepol/src/services.c index 7fac4a0..43ec07e 100644 --- a/libsepol/src/services.c +++ b/libsepol/src/services.c @@ -43,6 +43,11 @@ * Implementation of the security services. */ +/* The initial sizes malloc'd for sepol_compute_av_reason_buffer() support */ +#define REASON_BUF_SIZE 2048 +#define EXPR_BUF_SIZE 1024 +#define STACK_LEN 32 + #include #include #include @@ -54,6 +59,7 @@ #include #include #include +#include #include "debug.h" #include "private.h" @@ -70,6 +76,50 @@ static int selinux_enforcing = 1; static sidtab_t mysidtab, *sidtab = &mysidtab; static policydb_t mypolicydb, *policydb = &mypolicydb; +/* Used by sepol_compute_av_reason_buffer() to keep track of entries */ +static int reason_buf_used; +static int reason_buf_len; + +/* Stack services for RPN to infix conversion. */ +static char **stack; +static int stack_len; +static int next_stack_entry; + +static void push(char * expr_ptr) +{ + if (next_stack_entry >= stack_len) { + char **new_stack = stack; + int new_stack_len; + + if (stack_len == 0) + new_stack_len = STACK_LEN; + else + new_stack_len = stack_len * 2; + + new_stack = realloc(stack, new_stack_len * sizeof(*stack)); + if (!new_stack) { + ERR(NULL, "unable to allocate stack space"); + return; + } + stack_len = new_stack_len; + stack = new_stack; + } + stack[next_stack_entry] = expr_ptr; + next_stack_entry++; +} + +static char *pop(void) +{ + next_stack_entry--; + if (next_stack_entry < 0) { + next_stack_entry = 0; + ERR(NULL, "pop called with no stack entries"); + return NULL; + } + return stack[next_stack_entry]; +} +/* End Stack services */ + int hidden sepol_set_sidtab(sidtab_t * s) { sidtab = s; @@ -113,20 +163,195 @@ int sepol_set_policydb_from_file(FILE * fp) static uint32_t latest_granting = 0; /* - * Return the boolean value of a constraint expression - * when it is applied to the specified source and target + * cat_expr_buf adds a string to an expression buffer and handles realloc's if + * buffer is too small. The array of expression text buffer pointers and its + * counter are globally defined here as constraint_expr_eval_reason() sets + * them up and cat_expr_buf updates the e_buf pointer if the buffer is realloc'ed. + */ +static int expr_counter; +static char **expr_list; +static int expr_buf_used; +static int expr_buf_len; + +static void cat_expr_buf(char *e_buf, char *string) +{ + int len, new_buf_len; + char *p, *new_buf = e_buf; + + while (1) { + p = e_buf + expr_buf_used; + len = snprintf(p, expr_buf_len - expr_buf_used, "%s", string); + if (len < 0 || len >= expr_buf_len - expr_buf_used) { + new_buf_len = expr_buf_len + EXPR_BUF_SIZE; + new_buf = realloc(e_buf, new_buf_len); + if (!new_buf) { + ERR(NULL, "failed to realloc expr buffer"); + return; + } + /* Update the new ptr in the expr list and locally + new len */ + expr_list[expr_counter] = new_buf; + e_buf = new_buf; + expr_buf_len = new_buf_len; + } else { + expr_buf_used += len; + return; + } + } +} + +/* + * If the POLICY_KERN version is < POLICYDB_VERSION_CONSTRAINT_NAMES, + * then just return. + * + * If the POLICY_KERN version is >= POLICYDB_VERSION_CONSTRAINT_NAMES, + * then for 'types' only, read the types_names->types list as it will + * contain a list of types and attributes that were defined in the + * policy source. + */ +static void get_names_list(constraint_expr_t *e, int type) +{ + ebitmap_t *types; + types = &e->type_names->types; + int rc = 0; + unsigned int i; + char tmp_buf[128]; + /* if -type_names->types is 0, then output string */ + int empty_set = 0; + + if (policydb->policy_type == POLICY_KERN && + policydb->policyvers >= POLICYDB_VERSION_CONSTRAINT_NAMES && + type == CEXPR_TYPE) { + /* + * Process >= POLICYDB_VERSION_CONSTRAINT_NAMES with CEXPR_TYPE, then + * obtain the list of names defined in the policy source. + */ + cat_expr_buf(expr_list[expr_counter], "{ POLICY_SOURCE: "); + for (i = ebitmap_startbit(types); i < ebitmap_length(types); i++) { + if ((rc = ebitmap_get_bit(types, i)) == 0) + continue; + /* Collect entries */ + snprintf(tmp_buf, sizeof(tmp_buf), "%s ", policydb->p_type_val_to_name[i]); + cat_expr_buf(expr_list[expr_counter], tmp_buf); + empty_set++; + } + if (empty_set == 0) + cat_expr_buf(expr_list[expr_counter], " "); + cat_expr_buf(expr_list[expr_counter], "} "); + } + return; +} + +static void msgcat(char *src, char *tgt, char *rel, int failed) +{ + char tmp_buf[1024]; + if (failed) + snprintf(tmp_buf, sizeof(tmp_buf), "(%s %s %s -Fail-) ", + src, rel, tgt); + else + snprintf(tmp_buf, sizeof(tmp_buf), "(%s %s %s -Pass-) ", + src, rel, tgt); + cat_expr_buf(expr_list[expr_counter], tmp_buf); +} + +/* Returns a buffer with class, statement type and permissions */ +static char *get_class_info(sepol_security_class_t tclass, + constraint_node_t *constraint, + context_struct_t * xcontext) +{ + constraint_expr_t *e; + int mls, state_num; + + /* Find if MLS statement or not */ + mls = 0; + for (e = constraint->expr; e; e = e->next) { + if (e->attr >= CEXPR_L1L2) { + mls = 1; + break; + } + } + + /* Determine statement type */ + char *statements[] = { + "constrain ", /* 0 */ + "mlsconstrain ", /* 1 */ + "validatetrans ", /* 2 */ + "mlsvalidatetrans ", /* 3 */ + 0 }; + + if (xcontext == NULL) + state_num = mls + 0; + else + state_num = mls + 2; + + int class_buf_len = 0; + int new_class_buf_len; + int len, buf_used; + char *class_buf = NULL, *p; + char *new_class_buf = NULL; + + while (1) { + new_class_buf_len = class_buf_len + EXPR_BUF_SIZE; + new_class_buf = realloc(class_buf, new_class_buf_len); + if (!new_class_buf) + return NULL; + class_buf_len = new_class_buf_len; + class_buf = new_class_buf; + buf_used = 0; + p = class_buf; + + /* Add statement type */ + len = snprintf(p, class_buf_len - buf_used, "%s", statements[state_num]); + if (len < 0 || len >= class_buf_len - buf_used) + continue; + + /* Add class entry */ + p += len; + buf_used += len; + len = snprintf(p, class_buf_len - buf_used, "%s ", + policydb->p_class_val_to_name[tclass - 1]); + if (len < 0 || len >= class_buf_len - buf_used) + continue; + + /* Add permission entries */ + p += len; + buf_used += len; + len = snprintf(p, class_buf_len - buf_used, "{%s } (", + sepol_av_to_string(policydb, tclass, constraint->permissions)); + if (len < 0 || len >= class_buf_len - buf_used) + continue; + break; + } + return class_buf; +} + +/* + * Modified version of constraint_expr_eval that will process each + * constraint as before but adds the information to text buffers that + * will hold various components. The expression will be in RPN format, + * therefore there is a stack based RPN to infix converter to produce + * the final readable constraint. + * + * Return the boolean value of a constraint expression + * when it is applied to the specified source and target * security contexts. * * xcontext is a special beast... It is used by the validatetrans rules * only. For these rules, scontext is the context before the transition, * tcontext is the context after the transition, and xcontext is the context * of the process performing the transition. All other callers of - * constraint_expr_eval should pass in NULL for xcontext. + * constraint_expr_eval_reason should pass in NULL for xcontext. + * + * This function will also build a buffer as the constraint is processed + * for analysis. If this option is not required, then: + * 'tclass' should be '0' and r_buf MUST be NULL. */ -static int constraint_expr_eval(context_struct_t * scontext, +static int constraint_expr_eval_reason(context_struct_t * scontext, context_struct_t * tcontext, context_struct_t * xcontext, - constraint_expr_t * cexpr) + sepol_security_class_t tclass, + constraint_node_t *constraint, + char **r_buf, + unsigned int flags) { uint32_t val1, val2; context_struct_t *c; @@ -136,56 +361,137 @@ static int constraint_expr_eval(context_struct_t * scontext, int s[CEXPR_MAXDEPTH]; int sp = -1; - for (e = cexpr; e; e = e->next) { + char tmp_buf[128]; + +/* + * Define the s_t_x_num values that make up r1, t2 etc. in text strings + * Set 1 = source, 2 = target, 3 = xcontext for validatetrans + */ +#define SOURCE 1 +#define TARGET 2 +#define XTARGET 3 + + int s_t_x_num = SOURCE; + + /* Set 0 = fail, u = CEXPR_USER, r = CEXPR_ROLE, t = CEXPR_TYPE */ + int u_r_t = 0; + + char *name1, *name2; + char *src = NULL; + char *tgt = NULL; + + int rc = 0, x; + + char *class_buf = NULL; + + class_buf = get_class_info(tclass, constraint, xcontext); + if (!class_buf) { + ERR(NULL, "failed to allocate class buffer"); + return -ENOMEM; + } + + /* Original function but with buffer support */ + int expr_list_len = 0; + expr_counter = 0; + expr_list = NULL; + for (e = constraint->expr; e; e = e->next) { + /* Allocate a stack to hold expression buffer entries */ + if (expr_counter >= expr_list_len) { + char **new_expr_list = expr_list; + int new_expr_list_len; + + if (expr_list_len == 0) + new_expr_list_len = STACK_LEN; + else + new_expr_list_len = expr_list_len * 2; + + new_expr_list = realloc(expr_list, new_expr_list_len * sizeof(*expr_list)); + if (!new_expr_list) { + ERR(NULL, "failed to allocate expr buffer stack"); + rc = -ENOMEM; + goto out; + } + expr_list_len = new_expr_list_len; + expr_list = new_expr_list; + } + + /* + * malloc a buffer to store each expression text component. If the + * buffer is too small cat_expr_buf() will realloc extra space. + */ + expr_buf_len = EXPR_BUF_SIZE; + expr_list[expr_counter] = malloc(expr_buf_len); + if (!expr_list[expr_counter]) { + ERR(NULL, "failed to allocate expr buffer"); + rc = -ENOMEM; + goto out; + } + expr_buf_used = 0; + + /* Now process each expression of the constraint */ switch (e->expr_type) { case CEXPR_NOT: BUG_ON(sp < 0); s[sp] = !s[sp]; + cat_expr_buf(expr_list[expr_counter], "not"); break; case CEXPR_AND: BUG_ON(sp < 1); sp--; s[sp] &= s[sp + 1]; + cat_expr_buf(expr_list[expr_counter], "and"); break; case CEXPR_OR: BUG_ON(sp < 1); sp--; s[sp] |= s[sp + 1]; + cat_expr_buf(expr_list[expr_counter], "or"); break; case CEXPR_ATTR: if (sp == (CEXPR_MAXDEPTH - 1)) - return 0; + goto out; + switch (e->attr) { case CEXPR_USER: val1 = scontext->user; val2 = tcontext->user; + free(src); src = strdup("u1"); + free(tgt); tgt = strdup("u2"); break; case CEXPR_TYPE: val1 = scontext->type; val2 = tcontext->type; + free(src); src = strdup("t1"); + free(tgt); tgt = strdup("t2"); break; case CEXPR_ROLE: val1 = scontext->role; val2 = tcontext->role; r1 = policydb->role_val_to_struct[val1 - 1]; r2 = policydb->role_val_to_struct[val2 - 1]; + name1 = policydb->p_role_val_to_name[r1->s.value - 1]; + name2 = policydb->p_role_val_to_name[r2->s.value - 1]; + snprintf(tmp_buf, sizeof(tmp_buf), "r1=%s", name1); + free(src); src = strdup(tmp_buf); + snprintf(tmp_buf, sizeof(tmp_buf), "r2=%s ", name2); + free(tgt); tgt = strdup(tmp_buf); + switch (e->op) { case CEXPR_DOM: - s[++sp] = - ebitmap_get_bit(&r1->dominates, - val2 - 1); + s[++sp] = ebitmap_get_bit(&r1->dominates, val2 - 1); + msgcat(src, tgt, "dom", s[sp] == 0); + expr_counter++; continue; case CEXPR_DOMBY: - s[++sp] = - ebitmap_get_bit(&r2->dominates, - val1 - 1); + s[++sp] = ebitmap_get_bit(&r2->dominates, val1 - 1); + msgcat(src, tgt, "domby", s[sp] == 0); + expr_counter++; continue; case CEXPR_INCOMP: - s[++sp] = - (!ebitmap_get_bit - (&r1->dominates, val2 - 1) - && !ebitmap_get_bit(&r2->dominates, - val1 - 1)); + s[++sp] = (!ebitmap_get_bit(&r1->dominates, val2 - 1) + && !ebitmap_get_bit(&r2->dominates, val1 - 1)); + msgcat(src, tgt, "incomp", s[sp] == 0); + expr_counter++; continue; default: break; @@ -194,110 +500,327 @@ static int constraint_expr_eval(context_struct_t * scontext, case CEXPR_L1L2: l1 = &(scontext->range.level[0]); l2 = &(tcontext->range.level[0]); + free(src); src = strdup("l1"); + free(tgt); tgt = strdup("l2"); goto mls_ops; case CEXPR_L1H2: l1 = &(scontext->range.level[0]); l2 = &(tcontext->range.level[1]); + free(src); src = strdup("l1"); + free(tgt); tgt = strdup("h2"); goto mls_ops; case CEXPR_H1L2: l1 = &(scontext->range.level[1]); l2 = &(tcontext->range.level[0]); + free(src); src = strdup("h1"); + free(tgt); tgt = strdup("L2"); goto mls_ops; case CEXPR_H1H2: l1 = &(scontext->range.level[1]); l2 = &(tcontext->range.level[1]); + free(src); src = strdup("h1"); + free(tgt); tgt = strdup("h2"); goto mls_ops; case CEXPR_L1H1: l1 = &(scontext->range.level[0]); l2 = &(scontext->range.level[1]); + free(src); src = strdup("l1"); + free(tgt); tgt = strdup("h1"); goto mls_ops; case CEXPR_L2H2: l1 = &(tcontext->range.level[0]); l2 = &(tcontext->range.level[1]); - goto mls_ops; - mls_ops: + free(src); src = strdup("l2"); + free(tgt); tgt = strdup("h2"); + mls_ops: switch (e->op) { case CEXPR_EQ: s[++sp] = mls_level_eq(l1, l2); + msgcat(src, tgt, "eq", s[sp] == 0); + expr_counter++; continue; case CEXPR_NEQ: s[++sp] = !mls_level_eq(l1, l2); + msgcat(src, tgt, "neq", s[sp] == 0); + expr_counter++; continue; case CEXPR_DOM: s[++sp] = mls_level_dom(l1, l2); + msgcat(src, tgt, "dom", s[sp] == 0); + expr_counter++; continue; case CEXPR_DOMBY: s[++sp] = mls_level_dom(l2, l1); + msgcat(src, tgt, "domby", s[sp] == 0); + expr_counter++; continue; case CEXPR_INCOMP: s[++sp] = mls_level_incomp(l2, l1); + msgcat(src, tgt, "incomp", s[sp] == 0); + expr_counter++; continue; default: BUG(); - return 0; + goto out; } break; default: BUG(); - return 0; + goto out; } switch (e->op) { case CEXPR_EQ: s[++sp] = (val1 == val2); + msgcat(src, tgt, "eq", s[sp] == 0); break; case CEXPR_NEQ: s[++sp] = (val1 != val2); + msgcat(src, tgt, "neq", s[sp] == 0); break; default: BUG(); - return 0; + goto out; } break; case CEXPR_NAMES: if (sp == (CEXPR_MAXDEPTH - 1)) - return 0; + goto out; + s_t_x_num = SOURCE; c = scontext; - if (e->attr & CEXPR_TARGET) + if (e->attr & CEXPR_TARGET) { + s_t_x_num = TARGET; c = tcontext; - else if (e->attr & CEXPR_XTARGET) { + } else if (e->attr & CEXPR_XTARGET) { + s_t_x_num = XTARGET; c = xcontext; - if (!c) { - BUG(); - return 0; - } } - if (e->attr & CEXPR_USER) + if (!c) { + BUG(); + goto out; + } + if (e->attr & CEXPR_USER) { + u_r_t = CEXPR_USER; val1 = c->user; - else if (e->attr & CEXPR_ROLE) + name1 = policydb->p_user_val_to_name[val1 - 1]; + snprintf(tmp_buf, sizeof(tmp_buf), "u%d=%s ", + s_t_x_num, name1); + free(src); src = strdup(tmp_buf); + } + else if (e->attr & CEXPR_ROLE) { + u_r_t = CEXPR_ROLE; val1 = c->role; - else if (e->attr & CEXPR_TYPE) + name1 = policydb->p_role_val_to_name[val1 - 1]; + snprintf(tmp_buf, sizeof(tmp_buf), "r%d=%s ", s_t_x_num, name1); + free(src); src = strdup(tmp_buf); + } + else if (e->attr & CEXPR_TYPE) { + u_r_t = CEXPR_TYPE; val1 = c->type; + name1 = policydb->p_type_val_to_name[val1 - 1]; + snprintf(tmp_buf, sizeof(tmp_buf), + "t%d=%s ", s_t_x_num, name1); + free(src); src = strdup(tmp_buf); + } else { BUG(); - return 0; + goto out; } switch (e->op) { case CEXPR_EQ: + switch (u_r_t) { + case CEXPR_USER: + free(tgt); tgt=strdup("USER_ENTRY"); + break; + case CEXPR_ROLE: + free(tgt); tgt=strdup("ROLE_ENTRY"); + break; + case CEXPR_TYPE: + free(tgt); tgt=strdup("TYPE_ENTRY"); + break; + default: + ERR(NULL, "unrecognized u_r_t Value: %d", u_r_t); + break; + } + s[++sp] = ebitmap_get_bit(&e->names, val1 - 1); + msgcat(src, tgt, "eq", s[sp] == 0); + if (s[sp] == 0) { + get_names_list(e, u_r_t); + } break; + case CEXPR_NEQ: + switch (u_r_t) { + case CEXPR_USER: + free(tgt); tgt=strdup("USER_ENTRY"); + break; + case CEXPR_ROLE: + free(tgt); tgt=strdup("ROLE_ENTRY"); + break; + case CEXPR_TYPE: + free(tgt); tgt=strdup("TYPE_ENTRY"); + break; + default: + ERR(NULL, "unrecognized u_r_t Value: %d", u_r_t); + break; + } + s[++sp] = !ebitmap_get_bit(&e->names, val1 - 1); + msgcat(src, tgt, "neq", s[sp] == 0); + if (s[sp] == 0) { + get_names_list(e, u_r_t); + } break; default: BUG(); - return 0; + goto out; } break; default: BUG(); - return 0; + goto out; } + expr_counter++; + } + + /* + * At this point each expression of the constraint is in + * expr_list[n+1] and in RPN format. Now convert to 'infix' + */ + + /* + * Save expr count but zero expr_counter to detect if 'BUG(); goto out;' + * was called as we need to release any used expr_list malloc's. Normally + * they are released by the RPN to infix code. + */ + int expr_count = expr_counter; + expr_counter = 0; + + /* + * The array of expression answer buffer pointers and counter. Generate + * the same number of answer buffer entries as expression buffers (as + * there will never be more required). + */ + char **answer_list; + int answer_counter = 0; + + answer_list = malloc(expr_count * sizeof(*answer_list)); + if (!answer_list) { + ERR(NULL, "failed to allocate answer stack"); + rc = -ENOMEM; + goto out; } - BUG_ON(sp != 0); - return s[0]; + /* The pop operands */ + char *a; + char *b; + int a_len, b_len; + + /* Convert constraint from RPN to infix notation. */ + for (x = 0; x != expr_count; x++) { + if (strncmp(expr_list[x], "and", 3) == 0 || strncmp(expr_list[x], + "or", 2) == 0) { + b = pop(); + b_len = strlen(b); + a = pop(); + a_len = strlen(a); + + /* get a buffer to hold the answer */ + answer_list[answer_counter] = malloc(a_len + b_len + 8); + if (!answer_list[answer_counter]) { + ERR(NULL, "failed to allocate answer buffer"); + rc = -ENOMEM; + goto out; + } + memset(answer_list[answer_counter], '\0', a_len + b_len + 8); + + sprintf(answer_list[answer_counter], "%s %s %s", a, expr_list[x], b); + push(answer_list[answer_counter++]); + free(a); + free(b); + } else if (strncmp(expr_list[x], "not", 3) == 0) { + b = pop(); + b_len = strlen(b); + + answer_list[answer_counter] = malloc(b_len + 8); + if (!answer_list[answer_counter]) { + ERR(NULL, "failed to allocate answer buffer"); + rc = -ENOMEM; + goto out; + } + memset(answer_list[answer_counter], '\0', b_len + 8); + + if (strncmp(b, "not", 3) == 0) + sprintf(answer_list[answer_counter], "%s (%s)", expr_list[x], b); + else + sprintf(answer_list[answer_counter], "%s%s", expr_list[x], b); + push(answer_list[answer_counter++]); + free(b); + } else { + push(expr_list[x]); + } + } + /* Get the final answer from tos and build constraint text */ + a = pop(); + + /* Constraint calculation: rc = 0 is denied, rc = 1 is granted */ + sprintf(tmp_buf,"Constraint %s\n", s[0] ? "GRANTED" : "DENIED"); + + int len, new_buf_len; + char *p, **new_buf = r_buf; + /* + * These contain the constraint components that are added to the + * callers reason buffer. + */ + char *buffers[] = { class_buf, a, "); ", tmp_buf, 0 }; + + /* + * This will add the constraints to the callers reason buffer (who is + * responsible for freeing the memory). It will handle any realloc's + * should the buffer be too short. + * The reason_buf_used and reason_buf_len counters are defined globally + * as multiple constraints can be in the buffer. + */ + if (r_buf && ((s[0] == 0) || ((s[0] == 1 && + (flags & SHOW_GRANTED) == SHOW_GRANTED)))) { + for (x = 0; buffers[x] != NULL; x++) { + while (1) { + p = *r_buf + reason_buf_used; + len = snprintf(p, reason_buf_len - reason_buf_used, "%s", buffers[x]); + if (len < 0 || len >= reason_buf_len - reason_buf_used) { + new_buf_len = reason_buf_len + REASON_BUF_SIZE; + *new_buf = realloc(*r_buf, new_buf_len); + if (!new_buf) { + ERR(NULL, "failed to realloc reason buffer"); + goto out1; + } + **r_buf = **new_buf; + reason_buf_len = new_buf_len; + continue; + } else { + reason_buf_used += len; + break; + } + } + } + } + +out1: + rc = s[0]; + free(a); + +out: + free(class_buf); + free(src); + free(tgt); + + if (expr_counter) { + for (x = 0; expr_list[x] != NULL; x++) + free(expr_list[x]); + } + return rc; } /* @@ -309,7 +832,9 @@ static int context_struct_compute_av(context_struct_t * scontext, sepol_security_class_t tclass, sepol_access_vector_t requested, struct sepol_av_decision *avd, - unsigned int *reason) + unsigned int *reason, + char **r_buf, + unsigned int flags) { constraint_node_t *constraint; struct role_allow *ra; @@ -384,8 +909,8 @@ static int context_struct_compute_av(context_struct_t * scontext, constraint = tclass_datum->constraints; while (constraint) { if ((constraint->permissions & (avd->allowed)) && - !constraint_expr_eval(scontext, tcontext, NULL, - constraint->expr)) { + !constraint_expr_eval_reason(scontext, tcontext, NULL, + tclass, constraint, r_buf, flags)) { avd->allowed = (avd->allowed) & ~(constraint->permissions); } @@ -460,8 +985,8 @@ int hidden sepol_validate_transition(sepol_security_id_t oldsid, constraint = tclass_datum->validatetrans; while (constraint) { - if (!constraint_expr_eval(ocontext, ncontext, tcontext, - constraint->expr)) { + if (!constraint_expr_eval_reason(ocontext, ncontext, tcontext, + 0, constraint, NULL, 0)) { return -EPERM; } constraint = constraint->next; @@ -494,11 +1019,59 @@ int hidden sepol_compute_av_reason(sepol_security_id_t ssid, } rc = context_struct_compute_av(scontext, tcontext, tclass, - requested, avd, reason); + requested, avd, reason, NULL, 0); out: return rc; } +/* + * sepol_compute_av_reason_buffer - the reason buffer is malloc'd to + * REASON_BUF_SIZE. If the buffer size is exceeded, then it is realloc'd + * in the constraint_expr_eval_reason() function. + */ +int hidden sepol_compute_av_reason_buffer(sepol_security_id_t ssid, + sepol_security_id_t tsid, + sepol_security_class_t tclass, + sepol_access_vector_t requested, + struct sepol_av_decision *avd, + unsigned int *reason, + char **reason_buf, + unsigned int flags) +{ + *reason_buf = malloc(REASON_BUF_SIZE); + if (!*reason_buf) { + ERR(NULL, "failed to allocate reason buffer"); + return -ENOMEM; + } + /* + * These are defined globally as the buffer can contain multiple + * constraint statements so need to keep track + */ + reason_buf_used = 0; + reason_buf_len = REASON_BUF_SIZE; + + context_struct_t *scontext = 0, *tcontext = 0; + int rc = 0; + + scontext = sepol_sidtab_search(sidtab, ssid); + if (!scontext) { + ERR(NULL, "unrecognized SID %d", ssid); + rc = -EINVAL; + goto out; + } + tcontext = sepol_sidtab_search(sidtab, tsid); + if (!tcontext) { + ERR(NULL, "unrecognized SID %d", tsid); + rc = -EINVAL; + goto out; + } + + rc = context_struct_compute_av(scontext, tcontext, tclass, + requested, avd, reason, reason_buf, flags); +out: + return rc; +} + int hidden sepol_compute_av(sepol_security_id_t ssid, sepol_security_id_t tsid, sepol_security_class_t tclass, @@ -511,6 +1084,70 @@ int hidden sepol_compute_av(sepol_security_id_t ssid, } /* + * Return a class ID associated with the class string specified by + * class_name. + */ +int hidden sepol_class_name_to_id(const char *class_name, + sepol_security_class_t *tclass) +{ + char *class = NULL; + sepol_security_class_t id; + + for (id = 1; ; id++) { + if ((class = policydb->p_class_val_to_name[id - 1]) == NULL) { + ERR(NULL, "could not convert %s to class id", class_name); + return STATUS_ERR; + } + if ((strcmp(class, class_name)) == 0) { + *tclass = id; + return STATUS_SUCCESS; + } + } +} + +/* + * Return access vector bit associated with the class ID and permission + * string. + */ +int hidden sepol_perm_name_to_av(sepol_security_class_t tclass, + const char *perm_name, + sepol_access_vector_t *av) +{ + class_datum_t *tclass_datum; + perm_datum_t *perm_datum; + + if (!tclass || tclass > policydb->p_classes.nprim) { + ERR(NULL, "unrecognized class %d", tclass); + return -EINVAL; + } + tclass_datum = policydb->class_val_to_struct[tclass - 1]; + + /* Check for unique perms then the common ones (if any) */ + perm_datum = (perm_datum_t *) + hashtab_search(tclass_datum->permissions.table, + (hashtab_key_t)perm_name); + if (perm_datum != NULL) { + *av = 0x1 << (perm_datum->s.value - 1); + return STATUS_SUCCESS; + } + + if (tclass_datum->comdatum == NULL) + goto out; + + perm_datum = (perm_datum_t *) + hashtab_search(tclass_datum->comdatum->permissions.table, + (hashtab_key_t)perm_name); + + if (perm_datum != NULL) { + *av = 0x1 << (perm_datum->s.value - 1); + return STATUS_SUCCESS; + } +out: + ERR(NULL, "could not convert %s to av bit", perm_name); + return STATUS_ERR; +} + +/* * Write the security context string representation of * the context associated with `sid' into a dynamically * allocated string of the correct size. Set `*scontext' @@ -1339,7 +1976,7 @@ int hidden sepol_get_user_sids(sepol_security_id_t fromsid, rc = context_struct_compute_av(fromcon, &usercon, SECCLASS_PROCESS, PROCESS__TRANSITION, - &avd, &reason); + &avd, &reason, NULL, 0); if (rc || !(avd.allowed & PROCESS__TRANSITION)) continue; rc = sepol_sidtab_context_to_sid(sidtab, &usercon, diff --git a/libsepol/src/write.c b/libsepol/src/write.c index 55992f8..6fe73e6 100644 --- a/libsepol/src/write.c +++ b/libsepol/src/write.c @@ -893,8 +893,11 @@ static int write_cons_helper(policydb_t * p, if (ebitmap_write(&e->names, fp)) { return POLICYDB_ERROR; } - if (p->policy_type != POLICY_KERN && - type_set_write(e->type_names, fp)) { + if ((p->policy_type != POLICY_KERN && + type_set_write(e->type_names, fp)) || + (p->policy_type == POLICY_KERN && + (p->policyvers >= POLICYDB_VERSION_CONSTRAINT_NAMES) && + type_set_write(e->type_names, fp))) { return POLICYDB_ERROR; } break;