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authorEric W. Biederman <ebiederm@xmission.com>2016-11-14 18:48:07 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-06 10:40:13 +0100
commite747b4ae3b6bca205d82e86366e140cdcbfb7731 (patch)
treeeb37a1d3d431363778fde364f726e49571ba8ec6 /include
parent48466c4772d2cfeb331395043f7edd8c5324ef1b (diff)
ptrace: Capture the ptracer's creds not PT_PTRACE_CAP
commit 64b875f7ac8a5d60a4e191479299e931ee949b67 upstream. When the flag PT_PTRACE_CAP was added the PTRACE_TRACEME path was overlooked. This can result in incorrect behavior when an application like strace traces an exec of a setuid executable. Further PT_PTRACE_CAP does not have enough information for making good security decisions as it does not report which user namespace the capability is in. This has already allowed one mistake through insufficient granulariy. I found this issue when I was testing another corner case of exec and discovered that I could not get strace to set PT_PTRACE_CAP even when running strace as root with a full set of caps. This change fixes the above issue with strace allowing stracing as root a setuid executable without disabling setuid. More fundamentaly this change allows what is allowable at all times, by using the correct information in it's decision. Fixes: 4214e42f96d4 ("v2.4.9.11 -> v2.4.9.12") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/capability.h1
-rw-r--r--include/linux/ptrace.h1
-rw-r--r--include/linux/sched.h1
3 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/capability.h b/include/linux/capability.h
index 6ce3eefe2769..6ffb67e10c06 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -243,6 +243,7 @@ static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode);
extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
+extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
/* audit system wants to get cap info from files as well */
extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 504c98a278d4..e13bfdf7f314 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -19,7 +19,6 @@
#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
#define PT_PTRACED 0x00000001
#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
-#define PT_PTRACE_CAP 0x00000004 /* ptracer can follow suid-exec */
#define PT_OPT_FLAG_SHIFT 3
/* PT_TRACE_* event enable flags */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index e9c009dc3a4a..75d9a57e212e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1656,6 +1656,7 @@ struct task_struct {
struct list_head cpu_timers[3];
/* process credentials */
+ const struct cred __rcu *ptracer_cred; /* Tracer's credentials at attach */
const struct cred __rcu *real_cred; /* objective and real subjective task
* credentials (COW) */
const struct cred __rcu *cred; /* effective (overridable) subjective task