Skip to main content

Browse the archive

https://github.com/torvalds/linux
13 June 2022, 11:31:42 UTC
Revision 982f7c2b2e6a28f8f266e075d92e19c0dd4c6e56 authored by Dan Rosenberg on 30 September 2010, 22:15:31 UTC, committed by Linus Torvalds on 01 October 2010, 17:50:58 UTC 
sys_semctl: fix kernel stack leakage
 
The semctl syscall has several code paths that lead to the leakage of
uninitialized kernel stack memory (namely the IPC_INFO, SEM_INFO,
IPC_STAT, and SEM_STAT commands) during the use of the older, obsolete
version of the semid_ds struct.

The copy_semid_to_user() function declares a semid_ds struct on the stack
and copies it back to the user without initializing or zeroing the
"sem_base", "sem_pending", "sem_pending_last", and "undo" pointers,
allowing the leakage of 16 bytes of kernel stack memory.

The code is still reachable on 32-bit systems - when calling semctl()
newer glibc's automatically OR the IPC command with the IPC_64 flag, but
invoking the syscall directly allows users to use the older versions of
the struct.

Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 64aab72
History
Tip revision: 982f7c2b2e6a28f8f266e075d92e19c0dd4c6e56 authored by Dan Rosenberg on 30 September 2010, 22:15:31 UTC
sys_semctl: fix kernel stack leakage
Tip revision: 982f7c2
File Mode Size
Documentation
arch
block
crypto
drivers
firmware
fs
include
init
ipc
kernel
lib
mm
net
samples
scripts
security
sound
tools
usr
virt
.gitignore -rw-r--r-- 936 bytes
.mailmap -rw-r--r-- 3.9 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 91.8 KB
Kbuild -rw-r--r-- 2.4 KB
MAINTAINERS -rw-r--r-- 173.8 KB
Makefile -rw-r--r-- 50.5 KB
README -rw-r--r-- 17.0 KB
REPORTING-BUGS -rw-r--r-- 3.3 KB

README

back to top