jimzah/openafs
1
0
Fork 0
mirror of https://git.openafs.org/openafs.git synced 2025-01-31 05:27:44 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

OPENAFS-SA-2018-003 budb: prevent unbounded input to BUDB_SaveText

Browse Source 
BUDB_SaveText is defined with an input parameter that is defined to XDR
as an unbounded array of chars:
   typedef char charListT<>;

RPCs with unbounded arrays as inputs are susceptible to remote
denial-of-service (DOS) attacks.  A malicious client may submit a
BUDB_SaveText request with an arbitrarily large array, forcing the budb
server to expend large amounts of network bandwidth, cpu cycles, and
heap memory to unmarshal the input.

Modify the XDR definition of charListT so it is bounded.  This typedef
is shared (as an OUT parameter) by BUDB_GetText and BUDB_DumpDB, but
fortunately all in-tree callers of the client routines specify the same
maximum length of 1024.

Note: However, SBUDB_SaveText server implementation seems to allow for up to
BLOCK_DATA_SIZE (2040) = BLOCKSIZE (2048) - sizeof(struct blockHeader)
(8), and it's unknown if any out-of-tree callers exist.  Since we do not need a
tight bound in order to avoid the DoS, use a somewhat higher maximum of
4096 bytes to leave a safety margin.

[kaduk@mit.edu: bump the margin to 4096; adjust commit message to match]

(cherry picked from commit 124445c0c47994f5e2efef30e86337c3c8ebc93f)

Change-Id: Ic34f8f9e7484b7503a223509d5d61b72e1298b35
This commit is contained in:
Mark Vitale 2018-07-05 23:51:37 -04:00 committed by Benjamin Kaduk
parent 4218dc0a2d
commit 87f199c141
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/budb/budb.rg
View File

@ -224,7 +224,7 @@ typedef struct budb_volumeEntry budb_volumeList<BUDB_MAX_RETURN_LIST>;
typedef struct budb_dumpEntry budb_dumpList<BUDB_MAX_RETURN_LIST>; typedef struct budb_dumpEntry budb_dumpList<BUDB_MAX_RETURN_LIST>;
typedef struct budb_tapeEntry budb_tapeList<BUDB_MAX_RETURN_LIST>; typedef struct budb_tapeEntry budb_tapeList<BUDB_MAX_RETURN_LIST>;
typedef afs_int32 budb_dumpsList<BUDB_MAX_RETURN_LIST>; typedef afs_int32 budb_dumpsList<BUDB_MAX_RETURN_LIST>;
typedef char charListT<>; typedef char charListT<4096>;
%#define BUDB_TEXT_COMPLETE 1 %#define BUDB_TEXT_COMPLETE 1