It may not be clear to all users of this API if the provided maxlen argument
refers to the maximum string length or the maximum buffer size.
In order to improve safety and convenience of this API, make it refer to
the maximum string length.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
When dealing with 64-bit integers in JSON documents, blobmsg_parse
becomes useless as blobmsg-json only uses BLOBMSG_TYPE_INT64 if the
value exceeds the range of a 32-bit integer, otherwise
BLOBMSG_TYPE_INT32 is used. This is because blobmsg-json parses the
JSON document ad-hoc without knowing the schema in advance and hence
a result of the design of blobmsg-json (and the absence of JSON
schema definitions).
In practise, this made code less readable as instead of using
blobmsg_parse() one had to to deal with *all* attributes manually just
to catch fields which can be both, BLOBMSG_TYPE_INT32 or
BLOBMSG_TYPE_INT64, but are always dealt with as uint64_t in code as
they potentially could exceed the 32-bit range.
To resolve this issue, introduce as special wildcard attribute
type BLOBMSG_CAST_INT64 which should only be used in policies used
by blobmsg_parse(). If used for an attribute in the policy,
blobmsg_parse shall accept all integer types and allow the user
to retrieve the value using the uint64_t blobmsg_cast_u64() and
int64_t blobmsg_cast_s64() functions which is also introduced by this
commit.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
blobmsg_check_attr_len was calling blobmsg_check_data for some, but not all
attribute types. These checks was missing for arrays and tables.
Additionally, the length check in blobmsg_check_data was a bit off, since
it was comparing the blobmsg data length against the raw blob attr length.
Fix this by checking the raw blob length against the buffer length in
blobmsg_hdr_from_blob
Signed-off-by: Felix Fietkau <nbd@nbd.name>
blobmsg_hdr_valid_namelen was omitted when name==false
The blob_len vs blobmsg_namelen changes were not taking into account
potential padding between name and data
Signed-off-by: Felix Fietkau <nbd@nbd.name>
blobmsg_check_array_len expects the length of the full attribute buffer,
not just the data length.
Due to other missing length checks (fixed in the next commit), this did
not show up as a test failure
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Starting with 75e300aeec ("blobmsg: fix wrong payload len passed from
blobmsg_check_array") blobmsg_check_array_len() gets *blob* length
passed as argument. It cannot be used with __blobmsg_for_each_attr()
which expects *data* length.
Use blobmsg_for_each_attr() which calculates *data* length on its own.
The same bug was already reported in the past and there was fix attempt
in the commit cd75136b13 ("blobmsg: fix wrong payload len passed from
blobmsg_check_array"). That change made blobmsg_check_attr_len() calls
fail however.
This is hopefully the correct & complete fix:
1. blobmsg_check_array_len() gets *blob* length
2. It calls blobmsg_check_attr_len() which requires *blob* length
3. It uses blobmsg_for_each_attr() which gets *data* length
This fixes iterating over random memory treated as attrs. That was
resulting in check failing randomly for totally correct blobs. It's
critical e.g. for procd project with its instance_fill_array() failing
and procd not starting services.
Fixes: 75e300aeec ("blobmsg: fix wrong payload len passed from blobmsg_check_array")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Fix incorrect use of blobmsg_len() on passed blobmsg to
blobmsg_check_array_len() introduced in commit 379cd33d19
("fix wrong payload len passed from blobmsg_check_array") by using correct
blob_len().
By using blobmsg_len() a value too small was passed to blobmsg_check_array()
which could lead to this function returning an error when there is none.
Fixes: 379cd33d19 ("fix wrong payload len passed from blobmsg_check_array")
Signed-off-by: Chris Nisbet <nischris@gmail.com>
[add fixes tag, rewrap commit message]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
Fix out of bounds read in blobmsg_parse and blobmsg_check_name. The
out of bounds read happens because blob_attr and blobmsg_hdr have
flexible array members, whose size is 0 in the corresponding sizeofs.
For example the __blob_for_each_attr macro checks whether rem >=
sizeof(struct blob_attr). However, what LibFuzzer discovered was,
if the input data was only 4 bytes, the data would be casted to blob_attr,
and later on blob_data(attr) would be called even though attr->data was empty.
The same issue could appear with data larger than 4 bytes, where data
wasn't empty, but contained only the start of the blobmsg_hdr struct,
and blobmsg_hdr name was empty. The bugs were discovered by fuzzing
blobmsg_parse and blobmsg_array_parse with LibFuzzer.
CC: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>
[refactored some checks, added fuzz inputs, adjusted unit test results]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Better safe than sorry and while at it add handling of possible
*printf() failures.
Reviewed-by: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Fix incorrect use of blob_raw_len() on passed blobmsg to
blobmsg_check_array_len() introduced in commit b0e21553ae ("blobmsg:
add _len variants for all attribute checking methods") by using correct
blobmsg_len().
This wrong (higher) length was then for example causing issues in
procd's instance_config_parse_command() where blobmsg_check_attr_list()
was failing sanity checking of service command, thus resulting in the
startup failures of some services like collectd, nlbwmon and samba4.
Ref: http://lists.infradead.org/pipermail/openwrt-devel/2019-December/020840.html
Fixes: b0e21553ae ("blobmsg: add _len variants for all attribute checking methods")
Reported-by: Hannu Nyman <hannu.nyman@welho.com>
Tested-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Fixes following warning reported by GCC 10.0.0 20191203:
blobmsg.c:234:2: error: 'strcpy' offset 6 from the object at 'attr' is out of the bounds of referenced subobject 'name' with type 'uint8_t[0]' {aka 'unsigned char[0]'} at offset 6 [-Werror=array-bounds]
234 | strcpy((char *) hdr->name, (const char *)name);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from blobmsg.c:16:
blobmsg.h:42:10: note: subobject 'name' declared here
42 | uint8_t name[];
| ^~~~
Reported-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Introduce _len variants of blobmsg attribute checking functions which
aims to provide safer implementation as those functions should limit all
memory accesses performed on the blob to the range [attr, attr + len]
(upper bound non inclusive) and thus should be suited for checking of
untrusted blob attributes.
While at it add some comments in order to make it clear.
Signed-off-by: Tobias Schramm <tobleminer@gmail.com>
[_safe -> _len, blobmsg_check_array_len fix, commit subject/desc facelift]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
blobmsg_check_attr_len adds a length limit specifying the max offset
from attr that can be read safely.
Signed-off-by: Tobias Schramm <tobleminer@gmail.com>
[rebased and reworked, line wrapped commit message, _safe -> _len]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Fixes following error found by the fuzzer:
==29774==ERROR: AddressSanitizer: heap-buffer-overflow
READ of size 1 at 0x6020004f1c56 thread T0
#0 strcmp sanitizer_common_interceptors.inc:442:3
#1 blobmsg_parse blobmsg.c:168:8
Signed-off-by: Petr Štetiar <ynezz@true.cz>
Fixes following compiler warnings:
blobmsg.c:242:39: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
blobmsg.c:248:23: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
ulog.c💯18: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
ulog.c:112:16: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
ulog.c:117:20: error: format string is not a string literal [-Werror,-Wformat-nonliteral]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
gcc-9 on x86/64 has reported following issues:
base64.c:173:17: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:230:18: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:238:18: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:242:22: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:252:18: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:256:22: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:266:18: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:315:27: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
base64.c:329:15: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
blob.c:207:11: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
blob.c:210:11: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
blob.c:243:31: error: comparison of integer expressions of different signedness: ‘int’ and ‘unsigned int’ [-Werror=sign-compare]
blob.c:246:31: error: comparison of integer expressions of different signedness: ‘int’ and ‘unsigned int’ [-Werror=sign-compare]
blob.h:245:37: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
blob.h:253:37: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
blobmsg.h:269:37: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
blobmsg_json.c:155:10: error: comparison of integer expressions of different signedness: ‘int’ and ‘size_t’ {aka ‘long unsigned int’} [-Werror=sign-compare]
examples/../blob.h:245:37: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
examples/../blobmsg.h:269:37: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
json_script.c:590:7: error: this statement may fall through [-Werror=implicit-fallthrough=]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
This adds support for double floating point type to make it more JSON
compatible. For type checking it also adds a stub BLOB_ATTR_DOUBLE type.
If necessary, the accessor functions for blob can be added later
Signed-off-by: André Gaul <andre@gaul.io>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Consistently handle allocation failures. Some functions are changed to
return bool or int instead of void to allow returning an error.
Also fix a buffer size miscalculation in lua/uloop and use _exit() instead
of exit() on errors after forking.
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
This primarily helps with simplifying the ubus APIs.
blobmsg header presence is indicated by the BLOB_ATTR_EXTENDED bit in
the id_len field.
This changes the format ABI, but not the API.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
