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authorMarkus Armbruster <armbru@redhat.com>2008-02-26 09:57:11 -0600
committerEric Van Hensbergen <ericvh@opteron.9grid.us>2008-05-14 19:23:25 -0500
commitb32a09db4fb9a87246ba4e7726a979ac4709ad97 (patch)
treeb84cf43745c329ccbcbd2671da91e729db8132ca /fs/9p
parentdd286422fefdcff784e8d336deeb88ce817e14db (diff)
add match_strlcpy() us it to make v9fs make uname and remotename parsing more robust
match_strcpy() is a somewhat creepy function: the caller needs to make sure that the destination buffer is big enough, and when he screws up or forgets, match_strcpy() happily overruns the buffer. There's exactly one customer: v9fs_parse_options(). I believe it currently can't overflow its buffer, but that's not exactly obvious. The source string is a substing of the mount options. The kernel silently truncates those to PAGE_SIZE bytes, including the terminating zero. See compat_sys_mount() and do_mount(). The destination buffer is obtained from __getname(), which allocates from name_cachep, which is initialized by vfs_caches_init() for size PATH_MAX. We're safe as long as PATH_MAX <= PAGE_SIZE. PATH_MAX is 4096. As far as I know, the smallest PAGE_SIZE is also 4096. Here's a patch that makes the code a bit more obviously correct. It doesn't depend on PATH_MAX <= PAGE_SIZE. Signed-off-by: Markus Armbruster <armbru@redhat.com> Cc: Latchesar Ionkov <lucho@ionkov.net> Cc: Jim Meyering <meyering@redhat.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Diffstat (limited to 'fs/9p')
-rw-r--r--fs/9p/v9fs.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 9b0f0222e8b..e307fbd34fa 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -125,10 +125,10 @@ static void v9fs_parse_options(struct v9fs_session_info *v9ses)
v9ses->afid = option;
break;
case Opt_uname:
- match_strcpy(v9ses->uname, &args[0]);
+ match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
break;
case Opt_remotename:
- match_strcpy(v9ses->aname, &args[0]);
+ match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
break;
case Opt_nodevmap:
v9ses->nodev = 1;