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libsepol: fix overflow and 0 length allocations

Browse source 
Throughout libsepol, values taken from sepolicy are used in
places where length == 0 or length == <saturated> matter,
find and fix these.

Also, correct any type mismatches noticed along the way.

Signed-off-by: William Roberts <william.c.roberts@intel.com>
This commit is contained in:
William Roberts 2016-08-16 10:28:37 -07:00 committed by James Carter
parent 02081779f3
commit 8673854fb8
7 changed files with 129 additions and 32 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
libsepol/src/conditional.c
View file

@ -589,7 +589,8 @@ int cond_read_bool(policydb_t * p,
goto err;
len = le32_to_cpu(buf[2]);
if (zero_or_saturated(len))
goto err;
key = malloc(len + 1);
if (!key)
goto err;

16
libsepol/src/context.c
View file

@ -10,6 +10,7 @@
#include "context.h"
#include "handle.h"
#include "mls.h"
#include "private.h"
/* ----- Compatibility ---- */
int policydb_context_isvalid(const policydb_t * p, const context_struct_t * c)
@ -297,10 +298,18 @@ int context_from_string(sepol_handle_t * handle,
char *con_cpy = NULL;
sepol_context_t *ctx_record = NULL;
if (zero_or_saturated(con_str_len)) {
ERR(handle, "Invalid context length");
goto err;
}
/* sepol_context_from_string expects a NULL-terminated string */
con_cpy = malloc(con_str_len + 1);
if (!con_cpy)
goto omem;
if (!con_cpy) {
ERR(handle, "out of memory");
goto err;
}
memcpy(con_cpy, con_str, con_str_len);
con_cpy[con_str_len] = '\0';
@ -315,9 +324,6 @@ int context_from_string(sepol_handle_t * handle,
sepol_context_free(ctx_record);
return STATUS_SUCCESS;
omem:
ERR(handle, "out of memory");
err:
ERR(handle, "could not create context structure");
free(con_cpy);

70
libsepol/src/context_record.c
View file

@ -5,6 +5,7 @@
#include "context_internal.h"
#include "debug.h"
#include "private.h"
struct sepol_context {
@ -279,44 +280,69 @@ int sepol_context_from_string(sepol_handle_t * handle,
hidden_def(sepol_context_from_string)
static inline int safe_sum(size_t *sum, const size_t augends[], const size_t cnt) {
size_t a, i;
*sum = 0;
for(i=0; i < cnt; i++) {
/* sum should not be smaller than the addend */
a = augends[i];
*sum += a;
if (*sum < a) {
return i;
}
}
return 0;
}
int sepol_context_to_string(sepol_handle_t * handle,
const sepol_context_t * con, char **str_ptr)
{
int rc;
const int user_sz = strlen(con->user);
const int role_sz = strlen(con->role);
const int type_sz = strlen(con->type);
const int mls_sz = (con->mls) ? strlen(con->mls) : 0;
const int total_sz = user_sz + role_sz + type_sz +
mls_sz + ((con->mls) ? 3 : 2);
char *str = NULL;
size_t total_sz, err;
const size_t sizes[] = {
strlen(con->user), /* user length */
strlen(con->role), /* role length */
strlen(con->type), /* type length */
(con->mls) ? strlen(con->mls) : 0, /* mls length */
((con->mls) ? 3 : 2) + 1 /* mls has extra ":" also null byte */
};
char *str = (char *)malloc(total_sz + 1);
if (!str)
goto omem;
err = safe_sum(&total_sz, sizes, ARRAY_SIZE(sizes));
if (err) {
ERR(handle, "invalid size, overflow at position: %zu", err);
goto err;
}
str = (char *)malloc(total_sz);
if (!str) {
ERR(handle, "out of memory");
goto err;
}
if (con->mls) {
rc = snprintf(str, total_sz + 1, "%s:%s:%s:%s",
rc = snprintf(str, total_sz, "%s:%s:%s:%s",
con->user, con->role, con->type, con->mls);
if (rc < 0 || (rc >= total_sz + 1)) {
ERR(handle, "print error");
goto err;
}
} else {
rc = snprintf(str, total_sz + 1, "%s:%s:%s",
rc = snprintf(str, total_sz, "%s:%s:%s",
con->user, con->role, con->type);
if (rc < 0 || (rc >= total_sz + 1)) {
ERR(handle, "print error");
goto err;
}
}
/*
* rc is >= 0 on the size_t cast and is safe to promote
* to an unsigned value.
*/
if (rc < 0 || (size_t)rc >= total_sz) {
ERR(handle, "print error");
goto err;
}
*str_ptr = str;
return STATUS_SUCCESS;
omem:
ERR(handle, "out of memory");
err:
ERR(handle, "could not convert context to string");
free(str);

13
libsepol/src/module.c
View file

@ -30,6 +30,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <inttypes.h>
#define SEPOL_PACKAGE_SECTION_FC 0xf97cff90
#define SEPOL_PACKAGE_SECTION_SEUSER 0x97cff91
@ -793,6 +794,12 @@ int sepol_module_package_info(struct sepol_policy_file *spf, int *type,
goto cleanup;
}
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len)) {
ERR(file->handle,
"invalid module name length: 0x%"PRIx32,
len);
goto cleanup;
}
*name = malloc(len + 1);
if (!*name) {
ERR(file->handle, "out of memory");
@ -814,6 +821,12 @@ int sepol_module_package_info(struct sepol_policy_file *spf, int *type,
goto cleanup;
}
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len)) {
ERR(file->handle,
"invalid module version length: 0x%"PRIx32,
len);
goto cleanup;
}
*version = malloc(len + 1);
if (!*version) {
ERR(file->handle, "out of memory");

4
libsepol/src/module_to_cil.c
View file

@ -47,6 +47,8 @@
#include <sepol/policydb/services.h>
#include <sepol/policydb/util.h>
#include "private.h"
#ifdef __GNUC__
# define UNUSED(x) UNUSED_ ## x __attribute__((__unused__))
#else
@ -124,7 +126,7 @@ static int get_line(char **start, char *end, char **line)
for (len = 0; p < end && *p != '\n' && *p != '\0'; p++, len++);
if (len == 0) {
if (zero_or_saturated(len)) {
rc = 0;
goto exit;
}

52
libsepol/src/policydb.c
View file

@ -1911,6 +1911,9 @@ static int perm_read(policydb_t * p
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
perdatum->s.value = le32_to_cpu(buf[1]);
key = malloc(len + 1);
@ -1949,6 +1952,9 @@ static int common_read(policydb_t * p, hashtab_t h, struct policy_file *fp)
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
comdatum->s.value = le32_to_cpu(buf[1]);
if (symtab_init(&comdatum->permissions, PERM_SYMTAB_SIZE))
@ -2092,7 +2098,11 @@ static int class_read(policydb_t * p, hashtab_t h, struct policy_file *fp)
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
len2 = le32_to_cpu(buf[1]);
if (is_saturated(len2))
goto bad;
cladatum->s.value = le32_to_cpu(buf[2]);
if (symtab_init(&cladatum->permissions, PERM_SYMTAB_SIZE))
@ -2199,6 +2209,9 @@ static int role_read(policydb_t * p, hashtab_t h, struct policy_file *fp)
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
role->s.value = le32_to_cpu(buf[1]);
if (policydb_has_boundary_feature(p))
role->bounds = le32_to_cpu(buf[2]);
@ -2287,6 +2300,9 @@ static int type_read(policydb_t * p, hashtab_t h, struct policy_file *fp)
goto bad;
len = le32_to_cpu(buf[pos]);
if (zero_or_saturated(len))
goto bad;
typdatum->s.value = le32_to_cpu(buf[++pos]);
if (policydb_has_boundary_feature(p)) {
uint32_t properties;
@ -2447,6 +2463,8 @@ int filename_trans_read(filename_trans_t **t, struct policy_file *fp)
if (rc < 0)
return -1;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
return -1;
name = calloc(len + 1, sizeof(*name));
if (!name)
@ -2556,6 +2574,9 @@ static int ocontext_read_xen(struct policydb_compat_info *info,
if (rc < 0)
return -1;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
return -1;
c->u.name = malloc(len + 1);
if (!c->u.name)
return -1;
@ -2618,6 +2639,8 @@ static int ocontext_read_selinux(struct policydb_compat_info *info,
if (rc < 0)
return -1;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
return -1;
c->u.name = malloc(len + 1);
if (!c->u.name)
return -1;
@ -2659,6 +2682,8 @@ static int ocontext_read_selinux(struct policydb_compat_info *info,
return -1;
c->v.behavior = le32_to_cpu(buf[0]);
len = le32_to_cpu(buf[1]);
if (zero_or_saturated(len))
return -1;
c->u.name = malloc(len + 1);
if (!c->u.name)
return -1;
@ -2719,7 +2744,7 @@ static int genfs_read(policydb_t * p, struct policy_file *fp)
uint32_t buf[1];
size_t nel, nel2, len, len2;
genfs_t *genfs_p, *newgenfs, *genfs;
unsigned int i, j;
size_t i, j;
ocontext_t *l, *c, *newc = NULL;
int rc;
@ -2733,6 +2758,8 @@ static int genfs_read(policydb_t * p, struct policy_file *fp)
if (rc < 0)
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
newgenfs = calloc(1, sizeof(genfs_t));
if (!newgenfs)
goto bad;
@ -2778,6 +2805,8 @@ static int genfs_read(policydb_t * p, struct policy_file *fp)
if (rc < 0)
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
newc->u.name = malloc(len + 1);
if (!newc->u.name) {
goto bad;
@ -2877,6 +2906,9 @@ static int user_read(policydb_t * p, hashtab_t h, struct policy_file *fp)
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
usrdatum->s.value = le32_to_cpu(buf[1]);
if (policydb_has_boundary_feature(p))
usrdatum->bounds = le32_to_cpu(buf[2]);
@ -2960,6 +2992,9 @@ static int sens_read(policydb_t * p
goto bad;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
levdatum->isalias = le32_to_cpu(buf[1]);
key = malloc(len + 1);
@ -3003,6 +3038,9 @@ static int cat_read(policydb_t * p
goto bad;
len = le32_to_cpu(buf[0]);
if(zero_or_saturated(len))
goto bad;
catdatum->s.value = le32_to_cpu(buf[1]);
catdatum->isalias = le32_to_cpu(buf[2]);
@ -3339,6 +3377,8 @@ static int filename_trans_rule_read(filename_trans_rule_t ** r, struct policy_fi
return -1;
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
return -1;
ftr->name = malloc(len + 1);
if (!ftr->name)
@ -3580,6 +3620,8 @@ static int scope_read(policydb_t * p, int symnum, struct policy_file *fp)
if (rc < 0)
goto cleanup;
key_len = le32_to_cpu(buf[0]);
if (zero_or_saturated(key_len))
goto cleanup;
key = malloc(key_len + 1);
if (!key)
goto cleanup;
@ -3664,8 +3706,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, unsigned verbose)
}
len = buf[1];
if (len > POLICYDB_STRING_MAX_LENGTH) {
ERR(fp->handle, "policydb string length too long ");
if (len == 0 || len > POLICYDB_STRING_MAX_LENGTH) {
ERR(fp->handle, "policydb string length %s ", len ? "too long" : "zero");
return POLICYDB_ERROR;
}
@ -3798,6 +3840,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, unsigned verbose)
goto bad;
}
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
if ((p->name = malloc(len + 1)) == NULL) {
goto bad;
}
@ -3809,6 +3853,8 @@ int policydb_read(policydb_t * p, struct policy_file *fp, unsigned verbose)
goto bad;
}
len = le32_to_cpu(buf[0]);
if (zero_or_saturated(len))
goto bad;
if ((p->version = malloc(len + 1)) == NULL) {
goto bad;
}

3
libsepol/src/private.h
View file

@ -45,6 +45,9 @@
#define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
#define is_saturated(x) (x == (typeof(x))-1)
#define zero_or_saturated(x) ((x == 0) || is_saturated(x))
/* Policy compatibility information. */
struct policydb_compat_info {
unsigned int type;