On Thu, Dec 19, 2013 at 08:07:39PM +0400, Reco wrote:
Hello, list.
Refuse following symlinks in virInitctlSetRunLevel.
A reasonable fallback for the next two patches, which apply fork-setns
technique recommended on this list.
---
src/util/virinitctl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/util/virinitctl.c b/src/util/virinitctl.c
index 64bc23a..5cea992 100644
--- a/src/util/virinitctl.c
+++ b/src/util/virinitctl.c
@@ -139,7 +139,7 @@ int virInitctlSetRunLevel(virInitctlRunLevel level,
return -1;
}
- if ((fd = open(path, O_WRONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY)) < 0)
{
+ if ((fd = open(path, O_WRONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW)) < 0) {
if (errno == ENOENT) {
ret = 0;
goto cleanup;
Unfortunately O_NOFOLLOW will still resolve a symlink for '/dev' itself.
AFAICT there is simply no safe way to open /proc/$pid/root/* files at
all if you don't trust the $pid.
Unless someone has bright ideas then I think we should just abandon any
and all use of /proc/$PID/root and mandate setns() for this. Yes it will
mean we require newer kernel for this functionality to work but that is
preferrable to an insecure impl I think.
NB, we are treating this issue as a public security flaw and will assign
a CVE for it soon.
Regards,
Daniel
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