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authorJeremy Huddleston Sequoia <jeremyhu@apple.com>2016-05-30 00:46:21 -0700
committerJeremy Huddleston Sequoia <jeremyhu@apple.com>2016-05-30 02:10:00 -0700
commit6972ea08ee5b2ef1cfbdc2fcaf14f06bbd391561 (patch)
treeecf928e65faa9bf2108b407cd4228cba0594253e
parentd967caa988eaabd9e84c82879e2f21bd33b952a7 (diff)
fserve: Fix a buffer read overrun in _fs_client_access
https://bugs.freedesktop.org/show_bug.cgi?id=83224 Found by clang's Address Sanitizer crac.num_auths = set_font_authorizations(&authorizations, &authlen, client); /* Work around bug in xfs versions up through modular release 1.0.8 which rejects CreateAC packets with num_auths = 0 & authlen < 4 */ if (crac.num_auths == 0) { authorizations = padding; authlen = 4; } else { authlen = (authlen + 3) & ~0x3; } crac.length = (sizeof (fsCreateACReq) + authlen) >> 2; crac.acid = cur->acid; _fs_add_req_log(conn, FS_CreateAC); _fs_write(conn, (char *) &crac, sizeof (fsCreateACReq)); _fs_write(conn, authorizations, authlen); In the case in the report, set_font_authorizations setup authorizations as a 34 byte buffer (and authlen set to 34 as one would expect). The following block changed authlen to 36 to make it 4byte aligned and the final _fs_write() caused us to read 36 bytes from this 34 byte buffer. This changes the incorrect size increase to instead use _fs_write_pad which takes care of the padding for us. Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
-rw-r--r--src/fc/fserve.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/src/fc/fserve.c b/src/fc/fserve.c
index fb1941d..708fc35 100644
--- a/src/fc/fserve.c
+++ b/src/fc/fserve.c
@@ -2856,14 +2856,12 @@ _fs_client_access (FSFpePtr conn, pointer client, Bool sync)
if (crac.num_auths == 0) {
authorizations = padding;
authlen = 4;
- } else {
- authlen = (authlen + 3) & ~0x3;
}
crac.length = (sizeof (fsCreateACReq) + authlen) >> 2;
crac.acid = cur->acid;
_fs_add_req_log(conn, FS_CreateAC);
_fs_write(conn, (char *) &crac, sizeof (fsCreateACReq));
- _fs_write(conn, authorizations, authlen);
+ _fs_write_pad(conn, authorizations, authlen);
/* ignore reply; we don't even care about it */
conn->curacid = 0;
cur->auth_generation = client_auth_generation(client);