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apparmor: make unpack_array return a trianary value
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currently unpack_array() does not return an error nor whether the
array is not present. The ability to detect an error or the array
not being present is needed so rework the unpack_array() to return
the needed information.

Signed-off-by: John Johansen <john.johansen@canonical.com>
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John Johansen committed Oct 3, 2022
1 parent ad596ea commit 371e50a
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Showing 2 changed files with 33 additions and 22 deletions.
43 changes: 27 additions & 16 deletions security/apparmor/policy_unpack.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,11 @@ struct aa_ext {
u32 version;
};

#define tri int
#define TRI_TRUE 1
#define TRI_NONE 0
#define TRI_FALSE -1

/* audit callback for unpack fields */
static void audit_cb(struct audit_buffer *ab, void *va)
{
Expand Down Expand Up @@ -344,22 +349,22 @@ static bool unpack_u64(struct aa_ext *e, u64 *data, const char *name)
return false;
}

static size_t unpack_array(struct aa_ext *e, const char *name)
static tri unpack_array(struct aa_ext *e, const char *name, u16 *size)
{
void *pos = e->pos;

if (unpack_nameX(e, AA_ARRAY, name)) {
int size;
if (!inbounds(e, sizeof(u16)))
goto fail;
size = (int)le16_to_cpu(get_unaligned((__le16 *) e->pos));
*size = le16_to_cpu(get_unaligned((__le16 *) e->pos));
e->pos += sizeof(u16);
return size;
return TRI_TRUE;
}

return TRI_NONE;
fail:
e->pos = pos;
return 0;
return TRI_FALSE;
}

static size_t unpack_blob(struct aa_ext *e, char **blob, const char *name)
Expand Down Expand Up @@ -477,11 +482,12 @@ static bool unpack_trans_table(struct aa_ext *e, struct aa_str_table *strs)

/* exec table is optional */
if (unpack_nameX(e, AA_STRUCT, "xtable")) {
int i, size;
u16 size;
int i;

size = unpack_array(e, NULL);
/* currently 2^24 bits entries 0-3 */
if (size > (1 << 24))
if (unpack_array(e, NULL, &size) != TRI_TRUE ||
size > (1 << 24))
/* currently 2^24 bits entries 0-3 */
goto fail;
table = kcalloc(size, sizeof(char *), GFP_KERNEL);
if (!table)
Expand Down Expand Up @@ -546,9 +552,11 @@ static bool unpack_xattrs(struct aa_ext *e, struct aa_profile *profile)
void *pos = e->pos;

if (unpack_nameX(e, AA_STRUCT, "xattrs")) {
int i, size;
u16 size;
int i;

size = unpack_array(e, NULL);
if (unpack_array(e, NULL, &size) != TRI_TRUE)
goto fail;
profile->xattr_count = size;
profile->xattrs = kcalloc(size, sizeof(char *), GFP_KERNEL);
if (!profile->xattrs)
Expand All @@ -573,10 +581,12 @@ static bool unpack_xattrs(struct aa_ext *e, struct aa_profile *profile)
static bool unpack_secmark(struct aa_ext *e, struct aa_profile *profile)
{
void *pos = e->pos;
int i, size;
u16 size;
int i;

if (unpack_nameX(e, AA_STRUCT, "secmark")) {
size = unpack_array(e, NULL);
if (unpack_array(e, NULL, &size) != TRI_TRUE)
goto fail;

profile->secmark = kcalloc(size, sizeof(struct aa_secmark),
GFP_KERNEL);
Expand Down Expand Up @@ -620,14 +630,15 @@ static bool unpack_rlimits(struct aa_ext *e, struct aa_profile *profile)

/* rlimits are optional */
if (unpack_nameX(e, AA_STRUCT, "rlimits")) {
int i, size;
u16 size;
int i;
u32 tmp = 0;
if (!unpack_u32(e, &tmp, NULL))
goto fail;
profile->rlimits.mask = tmp;

size = unpack_array(e, NULL);
if (size > RLIM_NLIMITS)
if (unpack_array(e, NULL, &size) != TRI_TRUE ||
size > RLIM_NLIMITS)
goto fail;
for (i = 0; i < size; i++) {
u64 tmp2 = 0;
Expand Down
12 changes: 6 additions & 6 deletions security/apparmor/policy_unpack_test.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -144,8 +144,8 @@ static void policy_unpack_test_unpack_array_with_null_name(struct kunit *test)

puf->e->pos += TEST_ARRAY_BUF_OFFSET;

array_size = unpack_array(puf->e, NULL);

KUNIT_EXPECT_EQ(test, unpack_array(puf->e, NULL, &array_size),
TRI_TRUE);
KUNIT_EXPECT_EQ(test, array_size, (u16)TEST_ARRAY_SIZE);
KUNIT_EXPECT_PTR_EQ(test, puf->e->pos,
puf->e->start + TEST_ARRAY_BUF_OFFSET + sizeof(u16) + 1);
Expand All @@ -159,8 +159,8 @@ static void policy_unpack_test_unpack_array_with_name(struct kunit *test)

puf->e->pos += TEST_NAMED_ARRAY_BUF_OFFSET;

array_size = unpack_array(puf->e, name);

KUNIT_EXPECT_EQ(test, unpack_array(puf->e, name, &array_size),
TRI_TRUE);
KUNIT_EXPECT_EQ(test, array_size, (u16)TEST_ARRAY_SIZE);
KUNIT_EXPECT_PTR_EQ(test, puf->e->pos,
puf->e->start + TEST_ARRAY_BUF_OFFSET + sizeof(u16) + 1);
Expand All @@ -175,8 +175,8 @@ static void policy_unpack_test_unpack_array_out_of_bounds(struct kunit *test)
puf->e->pos += TEST_NAMED_ARRAY_BUF_OFFSET;
puf->e->end = puf->e->start + TEST_ARRAY_BUF_OFFSET + sizeof(u16);

array_size = unpack_array(puf->e, name);

KUNIT_EXPECT_EQ(test, unpack_array(puf->e, name, &array_size),
TRI_TRUE);
KUNIT_EXPECT_EQ(test, array_size, 0);
KUNIT_EXPECT_PTR_EQ(test, puf->e->pos,
puf->e->start + TEST_NAMED_ARRAY_BUF_OFFSET);
Expand Down

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