diff options
| author | Lennart Poettering <lennart@poettering.net> | 2018-12-04 18:21:25 +0100 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2018-12-04 23:28:14 +0100 |
| commit | 085b39e9df957b4a0ae7276d22011ac5dd20bc06 (patch) | |
| tree | 947ae80c4b0de6055eb9bf9980df2458beeccfa6 /src/basic/socket-util.c | |
| parent | 836f9cfebd63aa4285c005a3ff1bd59b3315eaac (diff) | |
| download | systemd-085b39e9df957b4a0ae7276d22011ac5dd20bc06.tar.gz | |
socket-util: Let's trick out ubsan when it validate struct sockaddr_un.sun_path[]
Linux is stupid and sometimes returns a "struct sockaddr_un" that is
longer than its fields, as it NUL terminates .sun_path[] even if it has
full length. ubsan detects this, rightfully. Since this is a Linux
misdesign let's trick out ubsan a bit.
Fixes: #11024
Diffstat (limited to 'src/basic/socket-util.c')
| -rw-r--r-- | src/basic/socket-util.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c index 9e70cc8c36..91bf801cdf 100644 --- a/src/basic/socket-util.c +++ b/src/basic/socket-util.c @@ -661,9 +661,14 @@ int sockaddr_pretty( /* The name must have at least one character (and the leading NUL does not count) */ p = strdup("<unnamed>"); else { + /* Note that we calculate the path pointer here through the .un_buffer[] field, in order to + * outtrick bounds checking tools such as ubsan, which are too smart for their own good: on + * Linux the kernel may return sun_path[] data one byte longer than the declared size of the + * field. */ + char *path = (char*) sa->un_buffer + offsetof(struct sockaddr_un, sun_path); size_t path_len = salen - offsetof(struct sockaddr_un, sun_path); - if (sa->un.sun_path[0] == 0) { + if (path[0] == 0) { /* Abstract socket. When parsing address information from, we * explicitly reject overly long paths and paths with embedded NULs. * But we might get such a socket from the outside. Let's return @@ -671,17 +676,17 @@ int sockaddr_pretty( _cleanup_free_ char *e = NULL; - e = cescape_length(sa->un.sun_path + 1, path_len - 1); + e = cescape_length(path + 1, path_len - 1); if (!e) return -ENOMEM; p = strjoin("@", e); } else { - if (sa->un.sun_path[path_len - 1] == '\0') + if (path[path_len - 1] == '\0') /* We expect a terminating NUL and don't print it */ path_len --; - p = cescape_length(sa->un.sun_path, path_len); + p = cescape_length(path, path_len); } } if (!p) |