diff options
| author | Gustavo A. R. Silva <gustavo@embeddedor.com> | 2018-05-25 14:47:57 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-30 07:48:51 +0200 |
| commit | 34dedd5d7bb9f5e798a0d4ab882a64e8b8a9720f (patch) | |
| tree | 6dedc3082185ad6b255ba89d638eb1b63d4858f9 /kernel | |
| parent | e6b2c060e0dfa8fc841feae5c9383fa96e5dc4ac (diff) | |
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
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sys.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sys.c b/kernel/sys.c index 78947de6f969..6624919ef0e7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -53,6 +53,8 @@ #include <linux/uidgid.h> #include <linux/cred.h> +#include <linux/nospec.h> + #include <linux/kmsg_dump.h> /* Move somewhere else to avoid recompiling? */ #include <generated/utsrelease.h> @@ -1311,6 +1313,7 @@ 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); |