linux/fs
Hugh Dickins 7c2c7d9930 fix setuid sometimes wouldn't
check_unsafe_exec() also notes whether the fs_struct is being
shared by more threads than will get killed by the exec, and if so
sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid.
But /proc/<pid>/cwd and /proc/<pid>/root lookups make transient
use of get_fs_struct(), which also raises that sharing count.

This might occasionally cause a setuid program not to change euid,
in the same way as happened with files->count (check_unsafe_exec
also looks at sighand->count, but /proc doesn't raise that one).

We'd prefer exec not to unshare fs_struct: so fix this in procfs,
replacing get_fs_struct() by get_fs_path(), which does path_get
while still holding task_lock, instead of raising fs->count.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: stable@kernel.org
___

 fs/proc/base.c |   50 +++++++++++++++--------------------------------
 1 file changed, 16 insertions(+), 34 deletions(-)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-28 17:30:00 -07:00
..
9p
adfs
affs
afs
autofs
autofs4
befs
bfs
btrfs
cifs
coda
configfs
cramfs
debugfs
devpts
dlm
ecryptfs
efs
exportfs
ext2
ext3
ext4
fat
freevxfs
fuse
gfs2
hfs
hfsplus
hostfs
hpfs
hppfs
hugetlbfs
isofs
jbd
jbd2
jffs2
jfs
lockd
minix
ncpfs
nfs
nfs_common
nfsd
nls
notify
ntfs
ocfs2
omfs
openpromfs
partitions
proc fix setuid sometimes wouldn't 2009-03-28 17:30:00 -07:00
qnx4
quota
ramfs
reiserfs
romfs
smbfs
squashfs
sysfs
sysv
ubifs
udf
ufs
xfs
aio.c
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio-integrity.c
bio.c
block_dev.c
buffer.c
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c
compat.c fix setuid sometimes doesn't 2009-03-28 17:30:00 -07:00
dcache.c
dcookies.c
direct-io.c
drop_caches.c
eventfd.c
eventpoll.c
exec.c fix setuid sometimes doesn't 2009-03-28 17:30:00 -07:00
fcntl.c
fifo.c
file_table.c
file.c
filesystems.c
fs-writeback.c
generic_acl.c
inode.c
internal.h fix setuid sometimes doesn't 2009-03-28 17:30:00 -07:00
ioctl.c
ioprio.c
Kconfig
Kconfig.binfmt
libfs.c
locks.c
Makefile
mbcache.c
mpage.c
namei.c
namespace.c
nfsctl.c
no-block.c
open.c
pipe.c
pnode.c
pnode.h
posix_acl.c
read_write.c
read_write.h
readdir.c
select.c
seq_file.c
signalfd.c
splice.c
stack.c
stat.c
super.c
sync.c
timerfd.c
utimes.c
xattr_acl.c
xattr.c