Darkangeel_hd
/
lineage_android_kernel_samsung_jf
mirror of https://github.com/Darkangeel-hd/lineage_android_kernel_samsung_jf.git
1
0
Fork 0
Code Issues Releases Wiki Activity

kernel/sys.c: fix potential Spectre v1 issue 

commit 23d6aef74da86a33fa6bb75f79565e0a16ee97c2 upstream.

`resource' can be controlled by user-space, hence leading to a potential
exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

  kernel/sys.c:1474 __do_compat_sys_old_getrlimit() warn: potential spectre issue 'get_current()->signal->rlim' (local cap)
  kernel/sys.c:1455 __do_sys_old_getrlimit() warn: potential spectre issue 'get_current()->signal->rlim' (local cap)

Fix this by sanitizing *resource* before using it to index
current->signal->rlim

Notice that given that speculation windows are large, the policy is to
kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].

[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2

Change-Id: Ibe1fbfa97b6984a6efaa2811ef1bb395e567f2a9
Link: http://lkml.kernel.org/r/20180515030038.GA11822@embeddedor.com
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.16:
 - Drop changes to compat implementation, which is a wrapper for the
   regular implementation here
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This commit is contained in:
Gustavo A. R. Silva 2018-05-25 14:47:57 -07:00 committed by ShevT
parent 39523602e0
commit 5a3c48ebd5
1 changed files with 4 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
kernel/sys.c
View File

@ -57,6 +57,9 @@
#include <asm/io.h>
#include <asm/unistd.h>
/* Hardening for Spectre-v1 */
#include <linux/nospec.h>
#ifndef SET_UNALIGN_CTL
# define SET_UNALIGN_CTL(a,b) (-EINVAL)
#endif
@ -1504,6 +1507,7 @@ SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource,
if (resource >= RLIM_NLIMITS)
return -EINVAL;
resource = array_index_nospec(resource, RLIM_NLIMITS);
task_lock(current->group_leader);
x = current->signal->rlim[resource];
task_unlock(current->group_leader);