SELinux: new /proc/self/attr/ipccreate for explicite ipc object labeling

At this point in time IPC objects (semaphores, message queues, etc) were labeled with the label of the process which created them. This patch introduces a new /proc/self/attr/ipccreate which will allow a program to set the label on ipc objects it is about to create. This may be useful in future trusted applications but at this time I do not know of any application which needs this functionality, but it should allow better more understandable policy to control access to ipc objects.

In security/selinux/include/av_permissions.h the patch also adds a blank line at the end. This was the output after the change to the access_vectors in policy and I did not edit that file by hand.

Signed-off-by Eric Paris <[email protected]>

 fs/proc/base.c                               |    6 ++++++
 security/selinux/hooks.c                     |   12 ++++++++++--
 security/selinux/include/av_perm_to_string.h |    1 +
 security/selinux/include/av_permissions.h    |    2 ++
 security/selinux/include/objsec.h            |    1 +

fs/proc/base.c +6 -0

index 243a94a..5b8ed50 100644
@@ -132,6 +132,7 @@ #ifdef CONFIG_SECURITY
 	PROC_TGID_ATTR_FSCREATE,
 	PROC_TGID_ATTR_KEYCREATE,
 	PROC_TGID_ATTR_SOCKCREATE,
+	PROC_TGID_ATTR_IPCCREATE,
 #endif
 #ifdef CONFIG_AUDITSYSCALL
 	PROC_TGID_LOGINUID,

@@ -175,6 +176,7 @@ #ifdef CONFIG_SECURITY
 	PROC_TID_ATTR_FSCREATE,
 	PROC_TID_ATTR_KEYCREATE,
 	PROC_TID_ATTR_SOCKCREATE,
+	PROC_TID_ATTR_IPCCREATE,
 #endif
 #ifdef CONFIG_AUDITSYSCALL
 	PROC_TID_LOGINUID,

@@ -293,6 +295,7 @@ static struct pid_entry tgid_attr_stuff[
 	E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TGID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TGID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
+	E(PROC_TGID_ATTR_IPCCREATE, "ipccreate", S_IFREG|S_IRUGO|S_IWUGO),
 	{0,0,NULL,0}
 };
 static struct pid_entry tid_attr_stuff[] = {

@@ -302,6 +305,7 @@ static struct pid_entry tid_attr_stuff[]
 	E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
+	E(PROC_TID_ATTR_IPCCREATE, "ipccreate", S_IFREG|S_IRUGO|S_IWUGO),
 	{0,0,NULL,0}
 };
 #endif

@@ -1769,6 +1773,8 @@ #ifdef CONFIG_SECURITY
 		case PROC_TGID_ATTR_KEYCREATE:
 		case PROC_TID_ATTR_SOCKCREATE:
 		case PROC_TGID_ATTR_SOCKCREATE:
+		case PROC_TID_ATTR_IPCCREATE:
+		case PROC_TGID_ATTR_IPCCREATE:
 			inode->i_fop = &proc_pid_attr_operations;
 			break;
 #endif

security/selinux/hooks.c +10 -2

index 2e8b4df..717c6c8 100644
@@ -1618,10 +1618,11 @@ static int selinux_bprm_set_security(str
 	/* Default to the current task SID. */
 	bsec->sid = tsec->sid;
 
-	/* Reset fs, key, and sock SIDs on execve. */
+	/* Reset fs, key, ipc, and sock SIDs on execve. */
 	tsec->create_sid = 0;
 	tsec->keycreate_sid = 0;
 	tsec->sockcreate_sid = 0;
+	tsec->ipccreate_sid = 0;
 
 	if (tsec->exec_sid) {
 		newsid = tsec->exec_sid;

@@ -2679,6 +2680,7 @@ static int selinux_task_alloc_security(s
 	tsec2->create_sid = tsec1->create_sid;
 	tsec2->keycreate_sid = tsec1->keycreate_sid;
 	tsec2->sockcreate_sid = tsec1->sockcreate_sid;
+	tsec2->ipccreate_sid = tsec1->ipccreate_sid;
 
 	/* Retain ptracer SID across fork, if any.
 	   This will be reset by the ptrace hook upon any

@@ -3789,7 +3791,7 @@ static int ipc_alloc_security(struct tas
 
 	isec->sclass = sclass;
 	isec->ipc_perm = perm;
-	isec->sid = tsec->sid;
+	isec->sid = tsec->ipccreate_sid ? : tsec->sid;
 	perm->security = isec;
 
 	return 0;

@@ -4280,6 +4282,8 @@ static int selinux_getprocattr(struct ta
 		sid = tsec->keycreate_sid;
 	else if (!strcmp(name, "sockcreate"))
 		sid = tsec->sockcreate_sid;
+	else if (!strcmp(name, "ipccreate"))
+		sid = tsec->ipccreate_sid;
 	else
 		return -EINVAL;
 

@@ -4316,6 +4320,8 @@ static int selinux_setprocattr(struct ta
 		error = task_has_perm(current, p, PROCESS__SETKEYCREATE);
 	else if (!strcmp(name, "sockcreate"))
 		error = task_has_perm(current, p, PROCESS__SETSOCKCREATE);
+	else if (!strcmp(name, "ipccreate"))
+		error = task_has_perm(current, p, PROCESS__SETIPCCREATE);
 	else if (!strcmp(name, "current"))
 		error = task_has_perm(current, p, PROCESS__SETCURRENT);
 	else

@@ -4352,6 +4358,8 @@ static int selinux_setprocattr(struct ta
 		tsec->keycreate_sid = sid;
 	} else if (!strcmp(name, "sockcreate"))
 		tsec->sockcreate_sid = sid;
+	else if (!strcmp(name, "ipccreate"))
+		tsec->ipccreate_sid = sid;
 	else if (!strcmp(name, "current")) {
 		struct av_decision avd;
 

security/selinux/include/av_perm_to_string.h +1 -0

index 7c9b583..08a26db 100644
@@ -74,6 +74,7 @@
    S_(SECCLASS_PROCESS, PROCESS__EXECHEAP, "execheap")
    S_(SECCLASS_PROCESS, PROCESS__SETKEYCREATE, "setkeycreate")
    S_(SECCLASS_PROCESS, PROCESS__SETSOCKCREATE, "setsockcreate")
+   S_(SECCLASS_PROCESS, PROCESS__SETIPCCREATE, "setipccreate")
    S_(SECCLASS_MSGQ, MSGQ__ENQUEUE, "enqueue")
    S_(SECCLASS_MSG, MSG__SEND, "send")
    S_(SECCLASS_MSG, MSG__RECEIVE, "receive")

security/selinux/include/av_permissions.h +2 -0

index 69fd4b4..0bc6fca 100644
@@ -469,6 +469,7 @@ #define PROCESS__EXECSTACK              
 #define PROCESS__EXECHEAP                         0x08000000UL
 #define PROCESS__SETKEYCREATE                     0x10000000UL
 #define PROCESS__SETSOCKCREATE                    0x20000000UL
+#define PROCESS__SETIPCCREATE                     0x40000000UL
 
 #define IPC__CREATE                               0x00000001UL
 #define IPC__DESTROY                              0x00000002UL

@@ -969,3 +970,4 @@ #define KEY__SEARCH                     
 #define KEY__LINK                                 0x00000010UL
 #define KEY__SETATTR                              0x00000020UL
 #define KEY__CREATE                               0x00000040UL
+

security/selinux/include/objsec.h +1 -1

index 9401788..a14c2f5 100644
@@ -34,6 +34,7 @@ struct task_security_struct {
 	u32 create_sid;      /* fscreate SID */
 	u32 keycreate_sid;   /* keycreate SID */
 	u32 sockcreate_sid;  /* fscreate SID */
+	u32 ipccreate_sid;   /* ipccreate SID */
 	u32 ptrace_sid;      /* SID of ptrace parent */
 };
 
 
 
 
--

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At this point in time IPC objects (semaphores, message queues, etc) were labeled with the label of the process which created them. This patch introduces a new /proc/self/attr/ipccreate which will allow a program to set the label on ipc objects it is about to create. This may be useful in future trusted applications but at this time I do not know of any application which needs this functionality, but it should allow better more understandable policy to control access to ipc objects.

In security/selinux/include/av_permissions.h the patch also adds a blank line at the end. This was the output after the change to the access_vectors in policy and I did not edit that file by hand.

At this point in time IPC objects (semaphores, message queues, etc) were labeled with the label of the process which created them. This patch introduces a new /proc/self/attr/ipccreate which will allow a program to set the label on ipc objects it is about to create. This may be useful in future trusted applications but at this time I do not know of any application which needs this functionality, but it should allow better more understandable policy to control access to ipc objects.

In security/selinux/include/av_permissions.h the patch also adds a blank line at the end. This was the output after the change to the access_vectors in policy and I did not edit that file by hand.

Quoted 8 lines · Eric Paris

At this point in time IPC objects (semaphores, message queues, etc) were labeled with the label of the process which created them. This patch introduces a new /proc/self/attr/ipccreate which will allow a program to set the label on ipc objects it is about to create. This may be useful in future trusted applications but at this time I do not know of any application which needs this functionality, but it should allow better more understandable policy to control access to ipc objects.

Quoted 5 lines

In security/selinux/include/av_permissions.h the patch also adds a blank line at the end. This was the output after the change to the access_vectors in policy and I did not edit that file by hand.

This patch only adds a process permission for setipccreate, I think you need a permission check for the destination type (what you are labeling the ipc to), there are lots of potential info leaks even if the process can't subsequently write to the ipc.

--
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From: Karl MacMillan [mailto:[email protected]]

Quoted 2 lines · Joshua Brindle

Quoted 1 line · Eric Paris

At this point in time IPC objects (semaphores, message

queues, etc)

Quoted 1 line

Quoted 1 line

were labeled with the label of the process which created

them. This

Quoted 1 line

Quoted 1 line

patch introduces a new /proc/self/attr/ipccreate which

will allow a

Quoted 1 line

Quoted 1 line

program to set the label on ipc objects it is about to

create. This

Quoted 1 line

Quoted 1 line

may be useful in future trusted applications but at this

time I do

Quoted 1 line

Quoted 1 line

not know of any application which needs this

functionality, but it

Quoted 1 line

Quoted 1 line

should allow better more understandable policy to control

access to ipc objects.

Quoted 2 lines

Quoted 2 lines

In security/selinux/include/av_permissions.h the patch

also adds a

Quoted 1 line

Quoted 1 line

blank line at the end. This was the output after the

change to the

Quoted 6 lines

Quoted 3 lines

access_vectors in policy and I did not edit that file by hand.

This patch only adds a process permission for setipccreate, I think you need a permission check for the destination type (what you are labeling the ipc to), there are lots of potential info

leaks even if

Quoted 2 lines

the process can't subsequently write to the ipc.

This is covered by the existing create permissions on the IPC objects since this is not a relabel but object creation.

At this point in time SysV IPC objects (semaphores, message queues, etc) are labeled with the label of the process which created them. This patch introduces a new /proc/self/attr/ipccreate which will allow a program to set the label on ipc objects it is about to create. This may be useful in future trusted applications but at this time I do not know of any application which needs this functionality. It should allow for better more understandable policy to control access to ipc objects.

I also decided to leave the name ipccreate even though this does not clearly express that the patch does not cover posix message queues. The only name that seemed descriptive enough was sysvipccreate which just seemed incredibly long for little to no gain. I will address the issue of controlling posix message queue explicit labeling in a future patch.

A note of interest, this only leaves 1 bit in the process security class. I don't currently have any plans to use any more, but it is something to remember.

Signed-off-by Eric Paris <[email protected]>

 fs/proc/base.c                               |    6 ++++++
 security/selinux/hooks.c                     |   12 ++++++++++--
 security/selinux/include/av_perm_to_string.h |    1 +
 security/selinux/include/av_permissions.h    |    1 +
 security/selinux/include/objsec.h            |    1 +
 5 files changed, 19 insertions(+), 2 deletions(-)

fs/proc/base.c +6 -0

index 243a94a..5b8ed50 100644
@@ -132,6 +132,7 @@ #ifdef CONFIG_SECURITY
 	PROC_TGID_ATTR_FSCREATE,
 	PROC_TGID_ATTR_KEYCREATE,
 	PROC_TGID_ATTR_SOCKCREATE,
+	PROC_TGID_ATTR_IPCCREATE,
 #endif
 #ifdef CONFIG_AUDITSYSCALL
 	PROC_TGID_LOGINUID,

@@ -175,6 +176,7 @@ #ifdef CONFIG_SECURITY
 	PROC_TID_ATTR_FSCREATE,
 	PROC_TID_ATTR_KEYCREATE,
 	PROC_TID_ATTR_SOCKCREATE,
+	PROC_TID_ATTR_IPCCREATE,
 #endif
 #ifdef CONFIG_AUDITSYSCALL
 	PROC_TID_LOGINUID,

@@ -293,6 +295,7 @@ static struct pid_entry tgid_attr_stuff[
 	E(PROC_TGID_ATTR_FSCREATE, "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TGID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TGID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
+	E(PROC_TGID_ATTR_IPCCREATE, "ipccreate", S_IFREG|S_IRUGO|S_IWUGO),
 	{0,0,NULL,0}
 };
 static struct pid_entry tid_attr_stuff[] = {

@@ -302,6 +305,7 @@ static struct pid_entry tid_attr_stuff[]
 	E(PROC_TID_ATTR_FSCREATE,  "fscreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TID_ATTR_KEYCREATE, "keycreate", S_IFREG|S_IRUGO|S_IWUGO),
 	E(PROC_TID_ATTR_SOCKCREATE, "sockcreate", S_IFREG|S_IRUGO|S_IWUGO),
+	E(PROC_TID_ATTR_IPCCREATE, "ipccreate", S_IFREG|S_IRUGO|S_IWUGO),
 	{0,0,NULL,0}
 };
 #endif

@@ -1769,6 +1773,8 @@ #ifdef CONFIG_SECURITY
 		case PROC_TGID_ATTR_KEYCREATE:
 		case PROC_TID_ATTR_SOCKCREATE:
 		case PROC_TGID_ATTR_SOCKCREATE:
+		case PROC_TID_ATTR_IPCCREATE:
+		case PROC_TGID_ATTR_IPCCREATE:
 			inode->i_fop = &proc_pid_attr_operations;
 			break;
 #endif

security/selinux/hooks.c +10 -2

index 2e8b4df..717c6c8 100644
@@ -1618,10 +1618,11 @@ static int selinux_bprm_set_security(str
 	/* Default to the current task SID. */
 	bsec->sid = tsec->sid;
 
-	/* Reset fs, key, and sock SIDs on execve. */
+	/* Reset fs, key, ipc, and sock SIDs on execve. */
 	tsec->create_sid = 0;
 	tsec->keycreate_sid = 0;
 	tsec->sockcreate_sid = 0;
+	tsec->ipccreate_sid = 0;
 
 	if (tsec->exec_sid) {
 		newsid = tsec->exec_sid;

@@ -2679,6 +2680,7 @@ static int selinux_task_alloc_security(s
 	tsec2->create_sid = tsec1->create_sid;
 	tsec2->keycreate_sid = tsec1->keycreate_sid;
 	tsec2->sockcreate_sid = tsec1->sockcreate_sid;
+	tsec2->ipccreate_sid = tsec1->ipccreate_sid;
 
 	/* Retain ptracer SID across fork, if any.
 	   This will be reset by the ptrace hook upon any

@@ -3789,7 +3791,7 @@ static int ipc_alloc_security(struct tas
 
 	isec->sclass = sclass;
 	isec->ipc_perm = perm;
-	isec->sid = tsec->sid;
+	isec->sid = tsec->ipccreate_sid ? : tsec->sid;
 	perm->security = isec;
 
 	return 0;

@@ -4280,6 +4282,8 @@ static int selinux_getprocattr(struct ta
 		sid = tsec->keycreate_sid;
 	else if (!strcmp(name, "sockcreate"))
 		sid = tsec->sockcreate_sid;
+	else if (!strcmp(name, "ipccreate"))
+		sid = tsec->ipccreate_sid;
 	else
 		return -EINVAL;
 

@@ -4316,6 +4320,8 @@ static int selinux_setprocattr(struct ta
 		error = task_has_perm(current, p, PROCESS__SETKEYCREATE);
 	else if (!strcmp(name, "sockcreate"))
 		error = task_has_perm(current, p, PROCESS__SETSOCKCREATE);
+	else if (!strcmp(name, "ipccreate"))
+		error = task_has_perm(current, p, PROCESS__SETIPCCREATE);
 	else if (!strcmp(name, "current"))
 		error = task_has_perm(current, p, PROCESS__SETCURRENT);
 	else

@@ -4352,6 +4358,8 @@ static int selinux_setprocattr(struct ta
 		tsec->keycreate_sid = sid;
 	} else if (!strcmp(name, "sockcreate"))
 		tsec->sockcreate_sid = sid;
+	else if (!strcmp(name, "ipccreate"))
+		tsec->ipccreate_sid = sid;
 	else if (!strcmp(name, "current")) {
 		struct av_decision avd;
 

security/selinux/include/av_perm_to_string.h +1 -0

index 7c9b583..08a26db 100644
@@ -74,6 +74,7 @@
    S_(SECCLASS_PROCESS, PROCESS__EXECHEAP, "execheap")
    S_(SECCLASS_PROCESS, PROCESS__SETKEYCREATE, "setkeycreate")
    S_(SECCLASS_PROCESS, PROCESS__SETSOCKCREATE, "setsockcreate")
+   S_(SECCLASS_PROCESS, PROCESS__SETIPCCREATE, "setipccreate")
    S_(SECCLASS_MSGQ, MSGQ__ENQUEUE, "enqueue")
    S_(SECCLASS_MSG, MSG__SEND, "send")
    S_(SECCLASS_MSG, MSG__RECEIVE, "receive")

security/selinux/include/av_permissions.h +1 -0

index 69fd4b4..0bc6fca 100644
@@ -469,6 +469,7 @@ #define PROCESS__EXECSTACK              
 #define PROCESS__EXECHEAP                         0x08000000UL
 #define PROCESS__SETKEYCREATE                     0x10000000UL
 #define PROCESS__SETSOCKCREATE                    0x20000000UL
+#define PROCESS__SETIPCCREATE                     0x40000000UL
 
 #define IPC__CREATE                               0x00000001UL
 #define IPC__DESTROY                              0x00000002UL

security/selinux/include/objsec.h +1 -0

index 9401788..a14c2f5 100644
@@ -34,6 +34,7 @@ struct task_security_struct {
 	u32 create_sid;      /* fscreate SID */
 	u32 keycreate_sid;   /* keycreate SID */
 	u32 sockcreate_sid;  /* fscreate SID */
+	u32 ipccreate_sid;   /* ipccreate SID */
 	u32 ptrace_sid;      /* SID of ptrace parent */
 };
 

I also decided to leave the name ipccreate even though this does not clearly express that the patch does not cover posix message queues. The only name that seemed descriptive enough was sysvipccreate which just seemed incredibly long for little to no gain. I will address the issue of controlling posix message queue explicit labeling in a future patch.

A note of interest, this only leaves 1 bit in the process security class. I don't currently have any plans to use any more, but it is something to remember.

Quoted 3 lines

A note of interest, this only leaves 1 bit in the process security class. I don't currently have any plans to use any more, but it is something to remember.

Does anybody have a good plan for what to do when we run out?

Quoted 5 lines · On Thu, 27 Jul 2006, [email protected] wrote:

Quoted 3 lines

A note of interest, this only leaves 1 bit in the process security class. I don't currently have any plans to use any more, but it is something to remember.

Does anybody have a good plan for what to do when we run out?

Probably create another process class and abstract it so policy just sees a single class.

Quoted 5 lines · Eric Paris

I also decided to leave the name ipccreate even though this does not clearly express that the patch does not cover posix message queues. The only name that seemed descriptive enough was sysvipccreate which just seemed incredibly long for little to no gain. I will address the issue of controlling posix message queue explicit labeling in a future patch.

Will that require another bit?

At this point in time SysV IPC objects (semaphores, message queues, etc) are labeled with the label of the process which created them. This patch introduces a new /proc/self/attr/ipccreate which will allow a program to set the label on ipc objects it is about to create. This may be useful in future trusted applications but at this time I do not know of any application which needs this functionality.

Quoted 6 lines · Eric Paris

At this point in time SysV IPC objects (semaphores, message queues, etc) are labeled with the label of the process which created them. This patch introduces a new /proc/self/attr/ipccreate which will allow a program to set the label on ipc objects it is about to create. This may be useful in future trusted applications but at this time I do not know of any application which needs this functionality.

This makes it difficult to justify upstream.