sysctl: enable strict writes
SYSCTL_WRITES_WARN was added in commit f4aacea2f5d1 ("sysctl: allow for
strict write position handling"), and released in v3.16 in August of
2014. Since then I can find only 1 instance of non-zero offset
writing[1], and it was fixed immediately in CRIU[2]. As such, it
appears safe to flip this to the strict state now.
[1] https://www.google.com/search?q="when%20file%20position%20was%20not%200"
[2] http://lists.openvz.org/pipermail/criu/2015-April/019819.html
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c810f8a..9142036 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -173,7 +173,7 @@
#define SYSCTL_WRITES_WARN 0
#define SYSCTL_WRITES_STRICT 1
-static int sysctl_writes_strict = SYSCTL_WRITES_WARN;
+static int sysctl_writes_strict = SYSCTL_WRITES_STRICT;
static int proc_do_cad_pid(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);