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sd-rtnl: message - protect against SEGFAULT when reading messages

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Make sure the returned data fits the datatype we requested. Otherwise return -EIO.

Also fix a broken test that this exposed.
This commit is contained in:
Tom Gundersen 2014-03-23 21:44:47 +01:00
parent a212d0dadd
commit f66eeb6bb6
2 changed files with 26 additions and 10 deletions
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32
src/libsystemd/sd-rtnl/rtnl-message.c
View file

@ -807,6 +807,8 @@ int sd_rtnl_message_read(sd_rtnl_message *m, unsigned short *type, void **data)
}
int rtnl_message_read_internal(sd_rtnl_message *m, unsigned short type, void **data) {
struct rtattr *rta;
assert_return(m, -EINVAL);
assert_return(m->sealed, -EPERM);
assert_return(data, -EINVAL);
@ -816,9 +818,11 @@ int rtnl_message_read_internal(sd_rtnl_message *m, unsigned short type, void **d
if(!m->rta_offset_tb[type])
return -ENODATA;
*data = RTA_DATA((struct rtattr *)((uint8_t *) m->hdr + m->rta_offset_tb[type]));
rta = (struct rtattr*)((uint8_t *) m->hdr + m->rta_offset_tb[type]);
return 0;
*data = RTA_DATA(rta);
return RTA_PAYLOAD(rta);
}
int sd_rtnl_message_read_string(sd_rtnl_message *m, unsigned short type, char **data) {
@ -828,8 +832,10 @@ int sd_rtnl_message_read_string(sd_rtnl_message *m, unsigned short type, char **
assert_return(data, -EINVAL);
r = rtnl_message_read_internal(m, type, &attr_data);
if(r < 0)
if (r < 0)
return r;
else if (strnlen(attr_data, r) >= (size_t) r)
return -EIO;
*data = (char *) attr_data;
@ -843,8 +849,10 @@ int sd_rtnl_message_read_u8(sd_rtnl_message *m, unsigned short type, uint8_t *da
assert_return(data, -EINVAL);
r = rtnl_message_read_internal(m, type, &attr_data);
if(r < 0)
if (r < 0)
return r;
else if ((size_t) r < sizeof(uint8_t))
return -EIO;
*data = *(uint8_t *) attr_data;
@ -858,8 +866,10 @@ int sd_rtnl_message_read_u16(sd_rtnl_message *m, unsigned short type, uint16_t *
assert_return(data, -EINVAL);
r = rtnl_message_read_internal(m, type, &attr_data);
if(r < 0)
if (r < 0)
return r;
else if ((size_t) r < sizeof(uint16_t))
return -EIO;
*data = *(uint16_t *) attr_data;
@ -873,8 +883,10 @@ int sd_rtnl_message_read_u32(sd_rtnl_message *m, unsigned short type, uint32_t *
assert_return(data, -EINVAL);
r = rtnl_message_read_internal(m, type, &attr_data);
if(r < 0)
if (r < 0)
return r;
else if ((size_t)r < sizeof(uint32_t))
return -EIO;
*data = *(uint32_t *) attr_data;
@ -888,8 +900,10 @@ int sd_rtnl_message_read_ether_addr(sd_rtnl_message *m, unsigned short type, str
assert_return(data, -EINVAL);
r = rtnl_message_read_internal(m, type, &attr_data);
if(r < 0)
if (r < 0)
return r;
else if ((size_t)r < sizeof(struct ether_addr))
return -EIO;
memcpy(data, attr_data, sizeof(struct ether_addr));
@ -903,8 +917,10 @@ int sd_rtnl_message_read_in_addr(sd_rtnl_message *m, unsigned short type, struct
assert_return(data, -EINVAL);
r = rtnl_message_read_internal(m, type, &attr_data);
if(r < 0)
if (r < 0)
return r;
else if ((size_t)r < sizeof(struct in_addr))
return -EIO;
memcpy(data, attr_data, sizeof(struct in_addr));

4
src/libsystemd/sd-rtnl/test-rtnl.c
View file

@ -152,6 +152,7 @@ static void test_address_get(sd_rtnl *rtnl, int ifindex) {
sd_rtnl_message *m;
sd_rtnl_message *r;
struct in_addr in_data;
char *label;
assert_se(sd_rtnl_message_new_addr(rtnl, &m, RTM_GETADDR, ifindex, AF_INET) >= 0);
assert_se(m);
@ -160,8 +161,7 @@ static void test_address_get(sd_rtnl *rtnl, int ifindex) {
assert_se(sd_rtnl_message_read_in_addr(r, IFA_LOCAL, &in_data) == 0);
assert_se(sd_rtnl_message_read_in_addr(r, IFA_ADDRESS, &in_data) == 0);
assert_se(sd_rtnl_message_read_in_addr(r, IFA_LABEL, &in_data) == 0);
assert_se(sd_rtnl_message_read_in_addr(r, IFA_CACHEINFO, &in_data) == 0);
assert_se(sd_rtnl_message_read_string(r, IFA_LABEL, &label) == 0);
assert_se(sd_rtnl_flush(rtnl) >= 0);
assert_se((m = sd_rtnl_message_unref(m)) == NULL);