[PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

Subsystems: networking [ipsec], selinux security module, the rest

STALE1786d

7 messages, 5 authors, 2021-09-15 · open the first message on its own page

[PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

From: Eugene Syromiatnikov <hidden>
Date: 2021-09-12 12:23:05

Commit 2d151d39073a ("xfrm: Add possibility to set the default to block
if we have no policy") broke ABI by changing the value of the XFRM_MSG_MAPPING
enum item, thus also evading the build-time check
in security/selinux/nlmsgtab.c:selinux_nlmsg_lookup for presence of proper
security permission checks in nlmsg_xfrm_perms.  Fix it by placing
XFRM_MSG_SETDEFAULT/XFRM_MSG_GETDEFAULT to the end of the enum, right before
__XFRM_MSG_MAX, and updating the nlmsg_xfrm_perms accordingly.

Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
References: https://lore.kernel.org/netdev/20210901151402.GA2557@altlinux.org/
Signed-off-by: Eugene Syromiatnikov <redacted>
---
v2:
 - Updated SELinux nlmsg_xfrm_perms permissions table and selinux_nlmsg_lookup
   build-time check accordingly.

v1: https://lore.kernel.org/lkml/20210901153407.GA20446@asgard.redhat.com/
---
 include/uapi/linux/xfrm.h   | 6 +++---
 security/selinux/nlmsgtab.c | 4 +++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h
index b96c1ea..26f456b1 100644
--- a/include/uapi/linux/xfrm.h
+++ b/include/uapi/linux/xfrm.h

@@ -213,13 +213,13 @@ enum {
 	XFRM_MSG_GETSPDINFO,
 #define XFRM_MSG_GETSPDINFO XFRM_MSG_GETSPDINFO
 
+	XFRM_MSG_MAPPING,
+#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING
+
 	XFRM_MSG_SETDEFAULT,
 #define XFRM_MSG_SETDEFAULT XFRM_MSG_SETDEFAULT
 	XFRM_MSG_GETDEFAULT,
 #define XFRM_MSG_GETDEFAULT XFRM_MSG_GETDEFAULT
-
-	XFRM_MSG_MAPPING,
-#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING
 	__XFRM_MSG_MAX
 };
 #define XFRM_MSG_MAX (__XFRM_MSG_MAX - 1)

diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
index d59276f..94ea2a8 100644
--- a/security/selinux/nlmsgtab.c
+++ b/security/selinux/nlmsgtab.c

@@ -126,6 +126,8 @@ static const struct nlmsg_perm nlmsg_xfrm_perms[] =
 	{ XFRM_MSG_NEWSPDINFO,	NETLINK_XFRM_SOCKET__NLMSG_WRITE },
 	{ XFRM_MSG_GETSPDINFO,	NETLINK_XFRM_SOCKET__NLMSG_READ  },
 	{ XFRM_MSG_MAPPING,	NETLINK_XFRM_SOCKET__NLMSG_READ  },
+	{ XFRM_MSG_SETDEFAULT,	NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_GETDEFAULT,	NETLINK_XFRM_SOCKET__NLMSG_READ  },
 };
 
 static const struct nlmsg_perm nlmsg_audit_perms[] =

@@ -189,7 +191,7 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
 		 * structures at the top of this file with the new mappings
 		 * before updating the BUILD_BUG_ON() macro!
 		 */
-		BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_MAPPING);
+		BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_GETDEFAULT);
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
 				 sizeof(nlmsg_xfrm_perms));
 		break;

-- 
2.1.4

Re: [PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

From: Antony Antony <hidden>
Date: 2021-09-13 07:00:57

Thanks!

Acked-by: Antony Antony <redacted>

-antony

On Sun, Sep 12, 2021 at 14:22:34 +0200, Eugene Syromiatnikov wrote:

quoted hunk

Commit 2d151d39073a ("xfrm: Add possibility to set the default to block
if we have no policy") broke ABI by changing the value of the XFRM_MSG_MAPPING
enum item, thus also evading the build-time check
in security/selinux/nlmsgtab.c:selinux_nlmsg_lookup for presence of proper
security permission checks in nlmsg_xfrm_perms.  Fix it by placing
XFRM_MSG_SETDEFAULT/XFRM_MSG_GETDEFAULT to the end of the enum, right before
__XFRM_MSG_MAX, and updating the nlmsg_xfrm_perms accordingly.

Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
References: https://lore.kernel.org/netdev/20210901151402.GA2557@altlinux.org/
Signed-off-by: Eugene Syromiatnikov <redacted>
---
v2:
 - Updated SELinux nlmsg_xfrm_perms permissions table and selinux_nlmsg_lookup
   build-time check accordingly.

v1: https://lore.kernel.org/lkml/20210901153407.GA20446@asgard.redhat.com/
---
 include/uapi/linux/xfrm.h   | 6 +++---
 security/selinux/nlmsgtab.c | 4 +++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h
index b96c1ea..26f456b1 100644
--- a/include/uapi/linux/xfrm.h
+++ b/include/uapi/linux/xfrm.h

@@ -213,13 +213,13 @@ enum {
 	XFRM_MSG_GETSPDINFO,
 #define XFRM_MSG_GETSPDINFO XFRM_MSG_GETSPDINFO
 
+	XFRM_MSG_MAPPING,
+#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING
+
 	XFRM_MSG_SETDEFAULT,
 #define XFRM_MSG_SETDEFAULT XFRM_MSG_SETDEFAULT
 	XFRM_MSG_GETDEFAULT,
 #define XFRM_MSG_GETDEFAULT XFRM_MSG_GETDEFAULT
-
-	XFRM_MSG_MAPPING,
-#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING
 	__XFRM_MSG_MAX
 };
 #define XFRM_MSG_MAX (__XFRM_MSG_MAX - 1)

diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
index d59276f..94ea2a8 100644
--- a/security/selinux/nlmsgtab.c
+++ b/security/selinux/nlmsgtab.c

@@ -126,6 +126,8 @@ static const struct nlmsg_perm nlmsg_xfrm_perms[] =
 	{ XFRM_MSG_NEWSPDINFO,	NETLINK_XFRM_SOCKET__NLMSG_WRITE },
 	{ XFRM_MSG_GETSPDINFO,	NETLINK_XFRM_SOCKET__NLMSG_READ  },
 	{ XFRM_MSG_MAPPING,	NETLINK_XFRM_SOCKET__NLMSG_READ  },
+	{ XFRM_MSG_SETDEFAULT,	NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+	{ XFRM_MSG_GETDEFAULT,	NETLINK_XFRM_SOCKET__NLMSG_READ  },
 };
 
 static const struct nlmsg_perm nlmsg_audit_perms[] =

@@ -189,7 +191,7 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
 		 * structures at the top of this file with the new mappings
 		 * before updating the BUILD_BUG_ON() macro!
 		 */
-		BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_MAPPING);
+		BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_GETDEFAULT);
 		err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
 				 sizeof(nlmsg_xfrm_perms));
 		break;

-- 
2.1.4

Re: [PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

From: Ondrej Mosnacek <omosnace@redhat.com>
Date: 2021-09-13 07:16:59

Hi,

On Sun, Sep 12, 2021 at 2:23 PM Eugene Syromiatnikov [off-list ref] wrote:

quoted hunk

Commit 2d151d39073a ("xfrm: Add possibility to set the default to block
if we have no policy") broke ABI by changing the value of the XFRM_MSG_MAPPING
enum item, thus also evading the build-time check
in security/selinux/nlmsgtab.c:selinux_nlmsg_lookup for presence of proper
security permission checks in nlmsg_xfrm_perms.  Fix it by placing
XFRM_MSG_SETDEFAULT/XFRM_MSG_GETDEFAULT to the end of the enum, right before
__XFRM_MSG_MAX, and updating the nlmsg_xfrm_perms accordingly.

Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
References: https://lore.kernel.org/netdev/20210901151402.GA2557@altlinux.org/
Signed-off-by: Eugene Syromiatnikov <redacted>
---
v2:
 - Updated SELinux nlmsg_xfrm_perms permissions table and selinux_nlmsg_lookup
   build-time check accordingly.

v1: https://lore.kernel.org/lkml/20210901153407.GA20446@asgard.redhat.com/
---
 include/uapi/linux/xfrm.h   | 6 +++---
 security/selinux/nlmsgtab.c | 4 +++-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/uapi/linux/xfrm.h b/include/uapi/linux/xfrm.h
index b96c1ea..26f456b1 100644
--- a/include/uapi/linux/xfrm.h
+++ b/include/uapi/linux/xfrm.h

@@ -213,13 +213,13 @@ enum {
        XFRM_MSG_GETSPDINFO,
 #define XFRM_MSG_GETSPDINFO XFRM_MSG_GETSPDINFO

+       XFRM_MSG_MAPPING,
+#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING
+
        XFRM_MSG_SETDEFAULT,
 #define XFRM_MSG_SETDEFAULT XFRM_MSG_SETDEFAULT
        XFRM_MSG_GETDEFAULT,
 #define XFRM_MSG_GETDEFAULT XFRM_MSG_GETDEFAULT
-
-       XFRM_MSG_MAPPING,
-#define XFRM_MSG_MAPPING XFRM_MSG_MAPPING

Perhaps it would be a good idea to put a comment here to make it less
likely that this repeats in the future. Something like:

/* IMPORTANT: Only insert new entries right above this line, otherwise
you break ABI! */

quoted hunk

        __XFRM_MSG_MAX
 };
 #define XFRM_MSG_MAX (__XFRM_MSG_MAX - 1)

diff --git a/security/selinux/nlmsgtab.c b/security/selinux/nlmsgtab.c
index d59276f..94ea2a8 100644
--- a/security/selinux/nlmsgtab.c
+++ b/security/selinux/nlmsgtab.c

@@ -126,6 +126,8 @@ static const struct nlmsg_perm nlmsg_xfrm_perms[] =
        { XFRM_MSG_NEWSPDINFO,  NETLINK_XFRM_SOCKET__NLMSG_WRITE },
        { XFRM_MSG_GETSPDINFO,  NETLINK_XFRM_SOCKET__NLMSG_READ  },
        { XFRM_MSG_MAPPING,     NETLINK_XFRM_SOCKET__NLMSG_READ  },
+       { XFRM_MSG_SETDEFAULT,  NETLINK_XFRM_SOCKET__NLMSG_WRITE },
+       { XFRM_MSG_GETDEFAULT,  NETLINK_XFRM_SOCKET__NLMSG_READ  },
 };

 static const struct nlmsg_perm nlmsg_audit_perms[] =

@@ -189,7 +191,7 @@ int selinux_nlmsg_lookup(u16 sclass, u16 nlmsg_type, u32 *perm)
                 * structures at the top of this file with the new mappings
                 * before updating the BUILD_BUG_ON() macro!
                 */
-               BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_MAPPING);
+               BUILD_BUG_ON(XFRM_MSG_MAX != XFRM_MSG_GETDEFAULT);
                err = nlmsg_perm(nlmsg_type, perm, nlmsg_xfrm_perms,
                                 sizeof(nlmsg_xfrm_perms));
                break;
--

2.1.4


-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.

Re: [PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

From: Eugene Syromiatnikov <hidden>
Date: 2021-09-13 10:23:39

On Mon, Sep 13, 2021 at 09:16:39AM +0200, Ondrej Mosnacek wrote:

Perhaps it would be a good idea to put a comment here to make it less
likely that this repeats in the future. Something like:

/* IMPORTANT: Only insert new entries right above this line, otherwise
you break ABI! */

Well, this statement is true for (almost) every UAPI-exposed enum, and
netlink is vast and relies on enums heavily.  I think it is already
mentioned somewhere in the documentation, and in the end it falls on the
shoulders of the maintainers—to pay additional attention to UAPI changes.

Re: [PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

From: Ondrej Mosnacek <omosnace@redhat.com>
Date: 2021-09-13 13:54:15

On Mon, Sep 13, 2021 at 12:23 PM Eugene Syromiatnikov [off-list ref] wrote:

On Mon, Sep 13, 2021 at 09:16:39AM +0200, Ondrej Mosnacek wrote:

quoted

Perhaps it would be a good idea to put a comment here to make it less
likely that this repeats in the future. Something like:

/* IMPORTANT: Only insert new entries right above this line, otherwise
you break ABI! */

Well, this statement is true for (almost) every UAPI-exposed enum, and
netlink is vast and relies on enums heavily.  I think it is already
mentioned somewhere in the documentation, and in the end it falls on the
shoulders of the maintainers—to pay additional attention to UAPI changes.

Ok, fair enough.

-- 
Ondrej Mosnacek
Software Engineer, Linux Security - SELinux kernel
Red Hat, Inc.

Re: [PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

From: Nicolas Dichtel <hidden>
Date: 2021-09-14 07:51:10

Le 12/09/2021 à 14:22, Eugene Syromiatnikov a écrit :

Commit 2d151d39073a ("xfrm: Add possibility to set the default to block
if we have no policy") broke ABI by changing the value of the XFRM_MSG_MAPPING
enum item, thus also evading the build-time check
in security/selinux/nlmsgtab.c:selinux_nlmsg_lookup for presence of proper
security permission checks in nlmsg_xfrm_perms.  Fix it by placing
XFRM_MSG_SETDEFAULT/XFRM_MSG_GETDEFAULT to the end of the enum, right before
__XFRM_MSG_MAX, and updating the nlmsg_xfrm_perms accordingly.

Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
References: https://lore.kernel.org/netdev/20210901151402.GA2557@altlinux.org/
Signed-off-by: Eugene Syromiatnikov <redacted>

Acked-by: Nicolas Dichtel <redacted>

Re: [PATCH v2] include/uapi/linux/xfrm.h: Fix XFRM_MSG_MAPPING ABI breakage

From: Steffen Klassert <steffen.klassert@secunet.com>
Date: 2021-09-15 08:52:00

On Sun, Sep 12, 2021 at 02:22:34PM +0200, Eugene Syromiatnikov wrote:

Commit 2d151d39073a ("xfrm: Add possibility to set the default to block
if we have no policy") broke ABI by changing the value of the XFRM_MSG_MAPPING
enum item, thus also evading the build-time check
in security/selinux/nlmsgtab.c:selinux_nlmsg_lookup for presence of proper
security permission checks in nlmsg_xfrm_perms.  Fix it by placing
XFRM_MSG_SETDEFAULT/XFRM_MSG_GETDEFAULT to the end of the enum, right before
__XFRM_MSG_MAX, and updating the nlmsg_xfrm_perms accordingly.

Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy")
References: https://lore.kernel.org/netdev/20210901151402.GA2557@altlinux.org/
Signed-off-by: Eugene Syromiatnikov <redacted>

Applied, thanks a lot Eugene!

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