coredump: make core dump functionality optional
Adds an expert Kconfig option, CONFIG_COREDUMP, which allows disabling of
core dump. This saves approximately 2.6k in the compiled kernel, and
complements CONFIG_ELF_CORE, which now depends on it.
CONFIG_COREDUMP also disables coredump-related sysctls, except for
suid_dumpable and related functions, which are necessary for ptrace.
[akpm@linux-foundation.org: fix binfmt_aout.c build]
Signed-off-by: Alex Kelly <alex.page.kelly@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>
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 84c76a3..c2a2f80 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -97,10 +97,12 @@
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern int max_threads;
-extern int core_uses_pid;
extern int suid_dumpable;
+#ifdef CONFIG_COREDUMP
+extern int core_uses_pid;
extern char core_pattern[];
extern unsigned int core_pipe_limit;
+#endif
extern int pid_max;
extern int min_free_kbytes;
extern int pid_max_min, pid_max_max;
@@ -177,8 +179,10 @@
static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
+#ifdef CONFIG_COREDUMP
static int proc_dostring_coredump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
+#endif
#ifdef CONFIG_MAGIC_SYSRQ
/* Note: sysrq code uses it's own private copy */
@@ -404,6 +408,7 @@
.mode = 0644,
.proc_handler = proc_dointvec,
},
+#ifdef CONFIG_COREDUMP
{
.procname = "core_uses_pid",
.data = &core_uses_pid,
@@ -425,6 +430,7 @@
.mode = 0644,
.proc_handler = proc_dointvec,
},
+#endif
#ifdef CONFIG_PROC_SYSCTL
{
.procname = "tainted",
@@ -2036,12 +2042,14 @@
static void validate_coredump_safety(void)
{
+#ifdef CONFIG_COREDUMP
if (suid_dumpable == SUID_DUMPABLE_SAFE &&
core_pattern[0] != '/' && core_pattern[0] != '|') {
printk(KERN_WARNING "Unsafe core_pattern used with "\
"suid_dumpable=2. Pipe handler or fully qualified "\
"core dump path required.\n");
}
+#endif
}
static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
@@ -2053,6 +2061,7 @@
return error;
}
+#ifdef CONFIG_COREDUMP
static int proc_dostring_coredump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
@@ -2061,6 +2070,7 @@
validate_coredump_safety();
return error;
}
+#endif
static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
void __user *buffer,