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authorKees Cook <keescook@chromium.org>2012-07-30 21:39:18 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 00:25:11 (GMT)
commit54b501992dd2a839e94e76aa392c392b55080ce8 (patch)
tree6d174fb95516f01e385d31d5ef87a248d8740fd2 /kernel/sysctl.c
parent9520628e8ceb69fa9a4aee6b57f22675d9e1b709 (diff)
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coredump: warn about unsafe suid_dumpable / core_pattern combo
When suid_dumpable=2, detect unsafe core_pattern settings and warn when they are seen. Signed-off-by: Kees Cook <keescook@chromium.org> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@linux.intel.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: James Morris <james.l.morris@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sysctl.c')
-rw-r--r--kernel/sysctl.c37
1 files changed, 35 insertions, 2 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 4ab1187..b46f496 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -174,6 +174,11 @@ static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
#endif
+static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
+static int proc_dostring_coredump(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
+
#ifdef CONFIG_MAGIC_SYSRQ
/* Note: sysrq code uses it's own private copy */
static int __sysrq_enabled = SYSRQ_DEFAULT_ENABLE;
@@ -410,7 +415,7 @@ static struct ctl_table kern_table[] = {
.data = core_pattern,
.maxlen = CORENAME_MAX_SIZE,
.mode = 0644,
- .proc_handler = proc_dostring,
+ .proc_handler = proc_dostring_coredump,
},
{
.procname = "core_pipe_limit",
@@ -1498,7 +1503,7 @@ static struct ctl_table fs_table[] = {
.data = &suid_dumpable,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec_minmax,
+ .proc_handler = proc_dointvec_minmax_coredump,
.extra1 = &zero,
.extra2 = &two,
},
@@ -2009,6 +2014,34 @@ int proc_dointvec_minmax(struct ctl_table *table, int write,
do_proc_dointvec_minmax_conv, &param);
}
+static void validate_coredump_safety(void)
+{
+ 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");
+ }
+}
+
+static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int error = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ if (!error)
+ validate_coredump_safety();
+ return error;
+}
+
+static int proc_dostring_coredump(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ int error = proc_dostring(table, write, buffer, lenp, ppos);
+ if (!error)
+ validate_coredump_safety();
+ return error;
+}
+
static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
void __user *buffer,
size_t *lenp, loff_t *ppos,