eCryptfs: Remove mmap from directory operations

backported from 38e3eaeedcac75360af8a92e7b66956ec4f334e5

Adrian reported that mkfontscale didn't work inside of eCryptfs mounts.
Strace revealed the following:

open("./", O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_DIRECTORY|O_CLOEXEC) = 3
fcntl64(3, F_GETFD) = 0x1 (flags FD_CLOEXEC)
open("./fonts.scale", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 4
getdents(3, /* 80 entries */, 32768) = 2304
open("./.", O_RDONLY) = 5
fcntl64(5, F_SETFD, FD_CLOEXEC) = 0
fstat64(5, {st_mode=S_IFDIR|0755, st_size=16384, ...}) = 0
mmap2(NULL, 16384, PROT_READ, MAP_PRIVATE, 5, 0) = 0xb7fcf000
close(5) = 0
 --- SIGBUS (Bus error) @ 0 (0) ---
 +++ killed by SIGBUS +++

The mmap2() on a directory was successful, resulting in a SIGBUS
signal later.  This patch removes mmap() from the list of possible
ecryptfs_dir_fops so that mmap() isn't possible on eCryptfs directory
files.

http://bugs.launchpad.net/bugs/400443

Reported-by: Adrian C. <anrxc@sysphere.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 45cb94c5e5d26eb3d139b6c4b8cdd22e61d1a13f..a6dc11b9378b3ead81ce6ce94216ff8b67f98671 100644 (file)
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -337,7 +337,6 @@ const struct file_operations ecryptfs_dir_fops = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl = ecryptfs_compat_ioctl,
 #endif
-       .mmap = generic_file_mmap,
        .open = ecryptfs_open,
        .flush = ecryptfs_flush,
        .release = ecryptfs_release,