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author | Riccardo Schirone <rschiron@redhat.com> | 2019-02-04 14:29:09 +0100 |
---|---|---|
committer | Lukas Nykryn <lnykryn@redhat.com> | 2019-04-08 13:43:16 +0200 |
commit | 9c2246f25010b9657b765c546c0e278d4824ab2c (patch) | |
tree | cffe0b32ae1eebb2f2cfaf15a226b1a5d47abea0 | |
parent | cce8d42c8d86167f22c86c226383a40dea28388a (diff) | |
download | systemd-9c2246f25010b9657b765c546c0e278d4824ab2c.tar.gz |
Refuse dbus message paths longer than BUS_PATH_SIZE_MAX limit.
Even though the dbus specification does not enforce any length limit on the
path of a dbus message, having to analyze too long strings in PID1 may be
time-consuming and it may have security impacts.
In any case, the limit is set so high that real-life applications should not
have a problem with it.
(cherry-picked from commit 61397a60d98e368a5720b37e83f3169e3eb511c4)
Related: #1678641
-rw-r--r-- | src/libsystemd/sd-bus/bus-internal.c | 2 | ||||
-rw-r--r-- | src/libsystemd/sd-bus/bus-internal.h | 4 |
2 files changed, 5 insertions, 1 deletions
diff --git a/src/libsystemd/sd-bus/bus-internal.c b/src/libsystemd/sd-bus/bus-internal.c index 7bb653338d..35e0b668ee 100644 --- a/src/libsystemd/sd-bus/bus-internal.c +++ b/src/libsystemd/sd-bus/bus-internal.c @@ -45,7 +45,7 @@ bool object_path_is_valid(const char *p) { if (slash) return false; - return true; + return (q - p) <= BUS_PATH_SIZE_MAX; } char* object_path_startswith(const char *a, const char *b) { diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h index 2087ef8eeb..90e6028983 100644 --- a/src/libsystemd/sd-bus/bus-internal.h +++ b/src/libsystemd/sd-bus/bus-internal.h @@ -333,6 +333,10 @@ struct sd_bus { #define BUS_MESSAGE_SIZE_MAX (128*1024*1024) #define BUS_AUTH_SIZE_MAX (64*1024) +/* Note that the D-Bus specification states that bus paths shall have no size limit. We enforce here one + * anyway, since truly unbounded strings are a security problem. The limit we pick is relatively large however, + * to not clash unnecessarily with real-life applications. */ +#define BUS_PATH_SIZE_MAX (64*1024) #define BUS_CONTAINER_DEPTH 128 |