redonkable
/
remarkable-linux
1
0
Fork 0
Code Releases Activity

coda: fix 'kernel memory exposure attempt' in fsync 

commit d337b66a4c upstream.

When an application called fsync on a file in Coda a small request with
just the file identifier was allocated, but the declared length was set
to the size of union of all possible upcall requests.

This bug has been around for a very long time and is now caught by the
extra checking in usercopy that was introduced in Linux-4.8.

The exposure happens when the Coda cache manager process reads the fsync
upcall request at which point it is killed. As a result there is nobody
servicing any further upcalls, trapping any processes that try to access
the mounted Coda filesystem.

Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Jan Harkes 2017-09-27 15:52:12 -04:00 committed by Greg Kroah-Hartman
parent cb58b8f8a8
commit 71d3850bf1
1 changed files with 1 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
fs/coda/upcall.c
View File

@ -447,8 +447,7 @@ int venus_fsync(struct super_block *sb, struct CodaFid *fid)
UPARG(CODA_FSYNC);
inp->coda_fsync.VFid = *fid;
error = coda_upcall(coda_vcp(sb), sizeof(union inputArgs),
&outsize, inp);
error = coda_upcall(coda_vcp(sb), insize, &outsize, inp);
CODA_FREE(inp, insize);
return error;