Commit graph

4 commits

Author SHA1 Message Date
Patrick Steinhardt
b35792dccb json: Remove invalid typedef redefinition
The C standard does not allow for typedef redefinitions, even if they
map to the same underlying type. In order to avoid including the
jsmn.h in json.h and thus exposing jsmn's internals, we have exactly
such a forward-declaring typedef in json.h. If enforcing the GNU99 C
standard, clang may generate a warning about this non-standard
construct.

Fix the issue by using a simple "struct jsmntok" forward declaration
instead of using a typedef.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Tested-by: Chuck Tuffli <chuck@freebsd.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-09-11 15:46:55 +02:00
Chris Coulson
dc052e5ac7 json: Avoid a double-free when parsing fails.
When grub_json_parse() succeeds, it returns the root object which
contains a pointer to the provided JSON string. Callers are
responsible for ensuring that this string outlives the root
object and for freeing its memory when it's no longer needed.

If grub_json_parse() fails to parse the provided JSON string,
it frees the string before returning an error. This results
in a double free in luks2_recover_key(), which also frees the
same string after grub_json_parse() returns an error.

This changes grub_json_parse() to never free the JSON string
passed to it, and updates the documentation for it to make it
clear that callers are responsible for ensuring that the string
outlives the root JSON object.

Fixes: CID 292465

Signed-off-by: Chris Coulson <chris.coulson@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-07-29 16:55:48 +02:00
Patrick Steinhardt
e933feb578 json: Get rid of casts for "jsmntok_t"
With the upstream change having landed that adds a name to the
previously anonymous "jsmntok" typedef, we can now add a forward
declaration for that struct in our code. As a result, we no longer have
to store the "tokens" member of "struct grub_json" as a void pointer but
can instead use the forward declaration, allowing us to get rid of casts
of that field.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-04-21 22:16:41 +02:00
Patrick Steinhardt
c6a84545a3 json: Implement wrapping interface
While the newly added jsmn library provides the parsing interface, it
does not provide any kind of interface to act on parsed tokens. Instead,
the caller is expected to handle pointer arithmetics inside of the token
array in order to extract required information. While simple, this
requires users to know some of the inner workings of the library and is
thus quite an unintuitive interface.

This commit adds a new interface on top of the jsmn parser that provides
convenience functions to retrieve values from the parsed json type, grub_json_t.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2020-01-10 14:13:22 +01:00