In the internal function sepol_av_to_string(), use a dynamically
allocated buffer for the permission names of an access vector instead
of a fixed static buffer to support very long permission names.
Update the internal users of sepol_av_to_string() to free the buffer.
The exported function sepol_perm_to_string() is just a wrapper to
the internal function. To avoid changing the behavior of this function,
use a static buffer and copy the resulting string from the internal
function. If the string is too long for the buffer or there was an
error in creating the string, return a string indicating the error.
All of the changes to the internal function and users was the work
of Christian Göttsche <cgzones@xxxxxxxxxxxxxx>.
Reported-by: oss-fuzz (issue 64832, 64933)
Suggested-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
Signed-off-by: James Carter <jwcart2@xxxxxxxxx>
---
v2: In sepol_av_perm_to_string():
- Use "sizeof(avbuf)" instead of 1024
- Added "free(avstr)"
In sepol_av_to_string():
- Added "*p = '\0';" to ensure buffer is initialized
checkpolicy/test/dismod.c | 11 +++---
checkpolicy/test/dispol.c | 7 ++--
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 | 26 ++++++++++++--
libsepol/src/util.c | 50 +++++++++++++++-----------
10 files changed, 103 insertions(+), 45 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/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..36e2368f 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, "(");
}
@@ -1237,7 +1239,25 @@ out:
const char *sepol_av_perm_to_string(sepol_security_class_t tclass,
sepol_access_vector_t av)
{
- return sepol_av_to_string(policydb, tclass, av);
+ static char avbuf[1024];
+ char *avstr = sepol_av_to_string(policydb, tclass, av);
+ size_t len;
+
+ memset(avbuf, 0, sizeof(avbuf));
+
+ if (avstr) {
+ len = strlen(avstr);
+ if (len < sizeof(avbuf)) {
+ strcpy(avbuf, avstr);
+ } else {
+ sprintf(avbuf, "<access-vector overflowed buffer>");
+ }
+ free(avstr);
+ } else {
+ sprintf(avbuf, "<format-failure>");
+ }
+
+ return avbuf;
}
/*
diff --git a/libsepol/src/util.c b/libsepol/src/util.c
index 2f877920..dcbdccf1 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 +82,27 @@ 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;
+ *p = '\0'; /* Just in case there are no permissions */
+ 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 +113,23 @@ 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))
--
2.43.0
