Use a growing dynamically allocated buffer to format permission names of an access vector instead of a fixed static buffer to support very long permission names. This changes the behavior of the since libsepol 3.4 exported function sepol_av_perm_to_string(): previously it returned a pointer to a static buffer which must not be free'd by the caller, now an allocated string which should be free'd by the caller (to avoid memory leaks). Reported-by: oss-fuzz (issue 64832, 64933) Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx> --- The oss-fuzz issue 64832 got closed by the latest fuzzer updates (due to unrelated changes that invalid the current reproducer), but the issue is still valid. Supersedes https://patchwork.kernel.org/project/selinux/patch/20231207165319.63889-1-cgzones@xxxxxxxxxxxxxx/ --- checkpolicy/test/dismod.c | 11 +++-- checkpolicy/test/dispol.c | 7 ++-- libsepol/include/sepol/policydb/services.h | 5 +-- libsepol/include/sepol/policydb/util.h | 2 +- libsepol/src/assertion.c | 16 +++++-- libsepol/src/hierarchy.c | 7 +++- libsepol/src/kernel_to_cil.c | 7 ++++ libsepol/src/kernel_to_conf.c | 15 +++++-- libsepol/src/module_to_cil.c | 7 ++++ libsepol/src/services.c | 8 ++-- libsepol/src/util.c | 49 ++++++++++++---------- libsepol/utils/sepol_compute_av.c | 25 ++++++++--- 12 files changed, 106 insertions(+), 53 deletions(-) diff --git a/checkpolicy/test/dismod.c b/checkpolicy/test/dismod.c index ac2d61d2..bd45c95e 100644 --- a/checkpolicy/test/dismod.c +++ b/checkpolicy/test/dismod.c @@ -118,12 +118,11 @@ static __attribute__((__noreturn__)) void usage(const char *progname) static void render_access_mask(uint32_t mask, uint32_t class, policydb_t * p, FILE * fp) { - char *perm; + char *perm = sepol_av_to_string(p, class, mask); fprintf(fp, "{"); - perm = sepol_av_to_string(p, class, mask); - if (perm) - fprintf(fp, "%s ", perm); + fprintf(fp, "%s ", perm ?: "<format-failure>"); fprintf(fp, "}"); + free(perm); } static void render_access_bitmap(ebitmap_t * map, uint32_t class, @@ -135,8 +134,8 @@ static void render_access_bitmap(ebitmap_t * map, uint32_t class, for (i = ebitmap_startbit(map); i < ebitmap_length(map); i++) { if (ebitmap_get_bit(map, i)) { perm = sepol_av_to_string(p, class, UINT32_C(1) << i); - if (perm) - fprintf(fp, "%s", perm); + fprintf(fp, "%s", perm ?: "<format-failure>"); + free(perm); } } fprintf(fp, " }"); diff --git a/checkpolicy/test/dispol.c b/checkpolicy/test/dispol.c index 944ef7ec..2662048e 100644 --- a/checkpolicy/test/dispol.c +++ b/checkpolicy/test/dispol.c @@ -93,12 +93,11 @@ static __attribute__((__noreturn__)) void usage(const char *progname) static int render_access_mask(uint32_t mask, avtab_key_t * key, policydb_t * p, FILE * fp) { - char *perm; + char *perm = sepol_av_to_string(p, key->target_class, mask); fprintf(fp, "{"); - perm = sepol_av_to_string(p, key->target_class, mask); - if (perm) - fprintf(fp, "%s ", perm); + fprintf(fp, "%s ", perm ?: "<format-failure>"); fprintf(fp, "}"); + free(perm); return 0; } diff --git a/libsepol/include/sepol/policydb/services.h b/libsepol/include/sepol/policydb/services.h index f2e311aa..c5889da5 100644 --- a/libsepol/include/sepol/policydb/services.h +++ b/libsepol/include/sepol/policydb/services.h @@ -106,10 +106,9 @@ extern int sepol_string_to_av_perm(sepol_security_class_t tclass, /* * Return a string representation of the permission av bit associated with * tclass. - * Returns a pointer to an internal buffer, overridden by the next call to - * this function or sepol_av_to_string(). + * The returned string must be free'd by the caller using free(3). */ - extern const char *sepol_av_perm_to_string(sepol_security_class_t tclass, +extern char *sepol_av_perm_to_string(sepol_security_class_t tclass, sepol_access_vector_t av); /* diff --git a/libsepol/include/sepol/policydb/util.h b/libsepol/include/sepol/policydb/util.h index db8da213..70c531d3 100644 --- a/libsepol/include/sepol/policydb/util.h +++ b/libsepol/include/sepol/policydb/util.h @@ -31,7 +31,7 @@ extern "C" { extern int add_i_to_a(uint32_t i, uint32_t * cnt, uint32_t ** a); -extern char *sepol_av_to_string(policydb_t * policydbp, uint32_t tclass, +extern char *sepol_av_to_string(const policydb_t *policydbp, sepol_security_class_t tclass, sepol_access_vector_t av); char *sepol_extended_perms_to_string(avtab_extended_perms_t *xperms); diff --git a/libsepol/src/assertion.c b/libsepol/src/assertion.c index 6de7d031..3076babe 100644 --- a/libsepol/src/assertion.c +++ b/libsepol/src/assertion.c @@ -48,26 +48,30 @@ static void report_failure(sepol_handle_t *handle, policydb_t *p, const avrule_t unsigned int stype, unsigned int ttype, const class_perm_node_t *curperm, uint32_t perms) { + char *permstr = sepol_av_to_string(p, curperm->tclass, perms); + if (avrule->source_filename) { ERR(handle, "neverallow on line %lu of %s (or line %lu of %s) violated by allow %s %s:%s {%s };", avrule->source_line, avrule->source_filename, avrule->line, policy_name(p), p->p_type_val_to_name[stype], p->p_type_val_to_name[ttype], p->p_class_val_to_name[curperm->tclass - 1], - sepol_av_to_string(p, curperm->tclass, perms)); + permstr ?: "<format-failure>"); } else if (avrule->line) { ERR(handle, "neverallow on line %lu violated by allow %s %s:%s {%s };", avrule->line, p->p_type_val_to_name[stype], p->p_type_val_to_name[ttype], p->p_class_val_to_name[curperm->tclass - 1], - sepol_av_to_string(p, curperm->tclass, perms)); + permstr ?: "<format-failure>"); } else { ERR(handle, "neverallow violated by allow %s %s:%s {%s };", p->p_type_val_to_name[stype], p->p_type_val_to_name[ttype], p->p_class_val_to_name[curperm->tclass - 1], - sepol_av_to_string(p, curperm->tclass, perms)); + permstr ?: "<format-failure>"); } + + free(permstr); } static int match_any_class_permissions(class_perm_node_t *cp, uint32_t class, uint32_t data) @@ -200,13 +204,17 @@ static int report_assertion_extended_permissions(sepol_handle_t *handle, /* failure on the regular permissions */ if (!found_xperm) { + char *permstr = sepol_av_to_string(p, curperm->tclass, perms); + ERR(handle, "neverallowxperm on line %lu of %s (or line %lu of %s) violated by\n" "allow %s %s:%s {%s };", avrule->source_line, avrule->source_filename, avrule->line, policy_name(p), p->p_type_val_to_name[stype], p->p_type_val_to_name[ttype], p->p_class_val_to_name[curperm->tclass - 1], - sepol_av_to_string(p, curperm->tclass, perms)); + permstr ?: "<format-failure>"); + + free(permstr); errors++; } diff --git a/libsepol/src/hierarchy.c b/libsepol/src/hierarchy.c index 350443a8..06e05310 100644 --- a/libsepol/src/hierarchy.c +++ b/libsepol/src/hierarchy.c @@ -443,12 +443,15 @@ static void bounds_report(sepol_handle_t *handle, policydb_t *p, uint32_t child, p->p_type_val_to_name[child - 1], p->p_type_val_to_name[parent - 1]); for (; cur; cur = cur->next) { + char *permstr = sepol_av_to_string(p, cur->key.target_class, cur->datum.data); + ERR(handle, " %s %s : %s { %s }", p->p_type_val_to_name[cur->key.source_type - 1], p->p_type_val_to_name[cur->key.target_type - 1], p->p_class_val_to_name[cur->key.target_class - 1], - sepol_av_to_string(p, cur->key.target_class, - cur->datum.data)); + permstr ?: "<format-failure>"); + + free(permstr); } } diff --git a/libsepol/src/kernel_to_cil.c b/libsepol/src/kernel_to_cil.c index bcb58eee..634826d5 100644 --- a/libsepol/src/kernel_to_cil.c +++ b/libsepol/src/kernel_to_cil.c @@ -297,6 +297,11 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey, } perms = sepol_av_to_string(pdb, class->s.value, curr->permissions); + if (!perms) { + ERR(NULL, "Failed to generate permission string"); + rc = -1; + goto exit; + } if (is_mls) { key_word = "mlsconstrain"; @@ -307,6 +312,7 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey, } rc = strs_create_and_add(strs, "(%s (%s (%s)) %s)", key_word, classkey, perms+1, expr); + free(perms); free(expr); if (rc != 0) { goto exit; @@ -1772,6 +1778,7 @@ static char *avtab_node_to_str(struct policydb *pdb, avtab_key_t *key, avtab_dat } rule = create_str("(%s %s %s (%s (%s)))", flavor, src, tgt, class, perms+1); + free(perms); } else if (key->specified & AVTAB_XPERMS) { perms = xperms_to_str(datum->xperms); if (perms == NULL) { diff --git a/libsepol/src/kernel_to_conf.c b/libsepol/src/kernel_to_conf.c index 83f46e0f..de1d9e09 100644 --- a/libsepol/src/kernel_to_conf.c +++ b/libsepol/src/kernel_to_conf.c @@ -292,6 +292,11 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey, } perms = sepol_av_to_string(pdb, class->s.value, curr->permissions); + if (!perms) { + ERR(NULL, "Failed to generate permission string"); + rc = -1; + goto exit; + } if (strchr(perms, ' ')) { perm_prefix = "{ "; perm_suffix = " }"; @@ -311,6 +316,7 @@ static int class_constraint_rules_to_strs(struct policydb *pdb, char *classkey, flavor, classkey, perm_prefix, perms+1, perm_suffix, expr); + free(perms); free(expr); if (rc != 0) { goto exit; @@ -1682,7 +1688,7 @@ static char *avtab_node_to_str(struct policydb *pdb, avtab_key_t *key, avtab_dat { uint32_t data = datum->data; type_datum_t *type; - const char *flavor, *src, *tgt, *class, *perms, *new; + const char *flavor, *src, *tgt, *class, *new; char *rule = NULL, *permstring; switch (0xFFF & key->specified) { @@ -1730,13 +1736,14 @@ static char *avtab_node_to_str(struct policydb *pdb, avtab_key_t *key, avtab_dat class = pdb->p_class_val_to_name[key->target_class - 1]; if (key->specified & AVTAB_AV) { - perms = sepol_av_to_string(pdb, key->target_class, data); - if (perms == NULL) { + permstring = sepol_av_to_string(pdb, key->target_class, data); + if (permstring == NULL) { ERR(NULL, "Failed to generate permission string"); goto exit; } rule = create_str("%s %s %s:%s { %s };", - flavor, src, tgt, class, perms+1); + flavor, src, tgt, class, permstring+1); + free(permstring); } else if (key->specified & AVTAB_XPERMS) { permstring = sepol_extended_perms_to_string(datum->xperms); if (permstring == NULL) { diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c index ee22dbbd..2ec66292 100644 --- a/libsepol/src/module_to_cil.c +++ b/libsepol/src/module_to_cil.c @@ -597,6 +597,7 @@ static int avrule_to_cil(int indent, struct policydb *pdb, uint32_t type, const rule, src, tgt, pdb->p_class_val_to_name[classperm->tclass - 1], perms + 1); + free(perms); } else { cil_println(indent, "(%s %s %s %s %s)", rule, src, tgt, @@ -1967,7 +1968,13 @@ static int constraints_to_cil(int indent, struct policydb *pdb, char *classkey, if (is_constraint) { perms = sepol_av_to_string(pdb, class->s.value, node->permissions); + if (perms == NULL) { + ERR(NULL, "Failed to generate permission string"); + rc = -1; + goto exit; + } cil_println(indent, "(%sconstrain (%s (%s)) %s)", mls, classkey, perms + 1, expr); + free(perms); } else { cil_println(indent, "(%svalidatetrans %s %s)", mls, classkey, expr); } diff --git a/libsepol/src/services.c b/libsepol/src/services.c index 0eeee7ec..e37221c8 100644 --- a/libsepol/src/services.c +++ b/libsepol/src/services.c @@ -347,9 +347,11 @@ static char *get_class_info(sepol_security_class_t tclass, p += len; buf_used += len; if (state_num < 2) { + char *permstr = sepol_av_to_string(policydb, tclass, constraint->permissions); + len = snprintf(p, class_buf_len - buf_used, "{%s } (", - sepol_av_to_string(policydb, tclass, - constraint->permissions)); + permstr ?: "<format-failure>"); + free(permstr); } else { len = snprintf(p, class_buf_len - buf_used, "("); } @@ -1234,7 +1236,7 @@ out: return STATUS_ERR; } - const char *sepol_av_perm_to_string(sepol_security_class_t tclass, +char *sepol_av_perm_to_string(sepol_security_class_t tclass, sepol_access_vector_t av) { return sepol_av_to_string(policydb, tclass, av); diff --git a/libsepol/src/util.c b/libsepol/src/util.c index 2f877920..1d4f0005 100644 --- a/libsepol/src/util.c +++ b/libsepol/src/util.c @@ -32,7 +32,7 @@ struct val_to_name { unsigned int val; - char *name; + const char *name; }; /* Add an unsigned integer to a dynamically reallocated array. *cnt @@ -82,20 +82,26 @@ static int perm_name(hashtab_key_t key, hashtab_datum_t datum, void *data) return 0; } -char *sepol_av_to_string(policydb_t * policydbp, uint32_t tclass, +char *sepol_av_to_string(const policydb_t *policydbp, sepol_security_class_t tclass, sepol_access_vector_t av) { struct val_to_name v; - static char avbuf[1024]; - class_datum_t *cladatum; - char *perm = NULL, *p; - unsigned int i; + const class_datum_t *cladatum = policydbp->class_val_to_struct[tclass - 1]; + uint32_t i; int rc; - int avlen = 0, len; + char *buffer = NULL, *p; + int len; + size_t remaining, size = 64; + +retry: + if (__builtin_mul_overflow(size, 2, &size)) + goto err; + p = realloc(buffer, size); + if (!p) + goto err; + buffer = p; + remaining = size; - memset(avbuf, 0, sizeof avbuf); - cladatum = policydbp->class_val_to_struct[tclass - 1]; - p = avbuf; for (i = 0; i < cladatum->permissions.nprim; i++) { if (av & (UINT32_C(1) << i)) { v.val = i + 1; @@ -106,22 +112,23 @@ char *sepol_av_to_string(policydb_t * policydbp, uint32_t tclass, permissions.table, perm_name, &v); } - if (rc) - perm = v.name; - if (perm) { - len = - snprintf(p, sizeof(avbuf) - avlen, " %s", - perm); - if (len < 0 - || (size_t) len >= (sizeof(avbuf) - avlen)) - return NULL; + if (rc == 1) { + len = snprintf(p, remaining, " %s", v.name); + if (len < 0) + goto err; + if ((size_t) len >= remaining) + goto retry; p += len; - avlen += len; + remaining -= len; } } } - return avbuf; + return buffer; + +err: + free(buffer); + return NULL; } #define next_bit_in_range(i, p) (((i) + 1 < sizeof(p)*8) && xperm_test(((i) + 1), p)) diff --git a/libsepol/utils/sepol_compute_av.c b/libsepol/utils/sepol_compute_av.c index d64dc31d..2ffc7a53 100644 --- a/libsepol/utils/sepol_compute_av.c +++ b/libsepol/utils/sepol_compute_av.c @@ -49,12 +49,27 @@ int main(int argc, char *argv[]) rc = sepol_compute_av(ssid, tsid, tclass, 0, &avd); switch (rc) { - case 0: - printf("allowed: %s\n", sepol_av_perm_to_string(tclass, avd.allowed)); - printf("decided: %s\n", sepol_av_perm_to_string(tclass, avd.decided)); - printf("auditallow: %s\n", sepol_av_perm_to_string(tclass, avd.auditallow)); - printf("auditdeny: %s\n", sepol_av_perm_to_string(tclass, avd.auditdeny)); + case 0: { + char *permstr; + + permstr = sepol_av_perm_to_string(tclass, avd.allowed); + printf("allowed: %s\n", permstr ?: "<format-failure>"); + free(permstr); + + permstr = sepol_av_perm_to_string(tclass, avd.decided); + printf("decided: %s\n", permstr ?: "<format-failure>"); + free(permstr); + + permstr = sepol_av_perm_to_string(tclass, avd.auditallow); + printf("auditallow: %s\n", permstr ?: "<format-failure>"); + free(permstr); + + permstr = sepol_av_perm_to_string(tclass, avd.auditdeny); + printf("auditdeny: %s\n", permstr ?: "<format-failure>"); + free(permstr); + break; + } case -EINVAL: printf("Invalid request\n"); break; -- 2.43.0
