diff mbox series

[v3] selinux: policydb - fix byte order and alignment issues

Message ID 20181017141512.4866-1-omosnace@redhat.com (mailing list archive)
State Superseded
Headers show
Series [v3] selinux: policydb - fix byte order and alignment issues | expand

Commit Message

Ondrej Mosnacek Oct. 17, 2018, 2:15 p.m. UTC 
Do the LE conversions before doing the Infiniband-related range checks.
The incorrect checks are otherwise causing a failure to load any policy
with an ibendportcon rule on BE systems. This can be reproduced by
running (on e.g. ppc64):

cat >my_module.cil <<EOF
(type test_ibendport_t)
(roletype object_r test_ibendport_t)
(ibendportcon mlx4_0 1 (system_u object_r test_ibendport_t ((s0) (s0))))
EOF
semodule -i my_module.cil

Also, fix loading/storing the 64-bit subnet prefix for OCON_IBPKEY to
use a correctly aligned buffer.

Finally, do not use the 'nodebuf' (u32) buffer where 'buf' (__le32)
should be used instead.

Tested internally on a ppc64 machine with a RHEL 7 kernel with this
patch applied.

Cc: Daniel Jurgens <danielj@mellanox.com>
Cc: Eli Cohen <eli@mellanox.com>
Cc: James Morris <jmorris@namei.org>
Cc: Doug Ledford <dledford@redhat.com>
Cc: <stable@vger.kernel.org> # 4.13+
Fixes: a806f7a1616f ("selinux: Create policydb version for Infiniband support")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 security/selinux/ss/policydb.c | 41 ++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 14 deletions(-)

Changes in v3:
 - use separate buffer for the 64-bit subnet_prefix
 - add comments on the byte ordering of subnet_prefix
 - deduplicate the le32_to_cpu() calls from checks

Changes in v2:
 - add reproducer to commit message
 - update e-mail address of James Morris
 - better Cc also the old SELinux ML

Comments

Stephen Smalley Oct. 17, 2018, 3:27 p.m. UTC | #1 
On 10/17/2018 10:15 AM, Ondrej Mosnacek wrote:
> Do the LE conversions before doing the Infiniband-related range checks.
> The incorrect checks are otherwise causing a failure to load any policy
> with an ibendportcon rule on BE systems. This can be reproduced by
> running (on e.g. ppc64):
> 
> cat >my_module.cil <<EOF
> (type test_ibendport_t)
> (roletype object_r test_ibendport_t)
> (ibendportcon mlx4_0 1 (system_u object_r test_ibendport_t ((s0) (s0))))
> EOF
> semodule -i my_module.cil
> 
> Also, fix loading/storing the 64-bit subnet prefix for OCON_IBPKEY to
> use a correctly aligned buffer.
> 
> Finally, do not use the 'nodebuf' (u32) buffer where 'buf' (__le32)
> should be used instead.
> 
> Tested internally on a ppc64 machine with a RHEL 7 kernel with this
> patch applied.
> 
> Cc: Daniel Jurgens <danielj@mellanox.com>
> Cc: Eli Cohen <eli@mellanox.com>
> Cc: James Morris <jmorris@namei.org>
> Cc: Doug Ledford <dledford@redhat.com>
> Cc: <stable@vger.kernel.org> # 4.13+
> Fixes: a806f7a1616f ("selinux: Create policydb version for Infiniband support")
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>

Acked-by: Stephen Smalley <sds@tycho.nsa.gov>

> ---
>   security/selinux/ss/policydb.c | 41 ++++++++++++++++++++++------------
>   1 file changed, 27 insertions(+), 14 deletions(-)
> 
> Changes in v3:
>   - use separate buffer for the 64-bit subnet_prefix
>   - add comments on the byte ordering of subnet_prefix
>   - deduplicate the le32_to_cpu() calls from checks
> 
> Changes in v2:
>   - add reproducer to commit message
>   - update e-mail address of James Morris
>   - better Cc also the old SELinux ML
> 
> diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
> index f4eadd3f7350..b9029491869b 100644
> --- a/security/selinux/ss/policydb.c
> +++ b/security/selinux/ss/policydb.c
> @@ -2108,6 +2108,7 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
>   {
>   	int i, j, rc;
>   	u32 nel, len;
> +	__be64 prefixbuf[1];
>   	__le32 buf[3];
>   	struct ocontext *l, *c;
>   	u32 nodebuf[8];
> @@ -2218,21 +2219,26 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
>   				break;
>   			}
>   			case OCON_IBPKEY:
> -				rc = next_entry(nodebuf, fp, sizeof(u32) * 4);
> +				rc = next_entry(prefixbuf, fp, sizeof(u64));
>   				if (rc)
>   					goto out;
>   
> -				c->u.ibpkey.subnet_prefix = be64_to_cpu(*((__be64 *)nodebuf));
> +				/* we need to have subnet_prefix in CPU order */
> +				c->u.ibpkey.subnet_prefix = be64_to_cpu(prefixbuf[0]);
>   
> -				if (nodebuf[2] > 0xffff ||
> -				    nodebuf[3] > 0xffff) {
> +				rc = next_entry(buf, fp, sizeof(u32) * 2);
> +				if (rc)
> +					goto out;
> +
> +				c->u.ibpkey.low_pkey  = le32_to_cpu(buf[0]);
> +				c->u.ibpkey.high_pkey = le32_to_cpu(buf[1]);
> +
> +				if (c->u.ibpkey.low_pkey  > 0xffff ||
> +				    c->u.ibpkey.high_pkey > 0xffff) {
>   					rc = -EINVAL;
>   					goto out;
>   				}
>   
> -				c->u.ibpkey.low_pkey = le32_to_cpu(nodebuf[2]);
> -				c->u.ibpkey.high_pkey = le32_to_cpu(nodebuf[3]);
> -
>   				rc = context_read_and_validate(&c->context[0],
>   							       p,
>   							       fp);
> @@ -2249,13 +2255,14 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
>   				if (rc)
>   					goto out;
>   
> -				if (buf[1] > 0xff || buf[1] == 0) {
> +				c->u.ibendport.port = le32_to_cpu(buf[1]);
> +
> +				if (c->u.ibendport.port > 0xff ||
> +				    c->u.ibendport.port == 0) {
>   					rc = -EINVAL;
>   					goto out;
>   				}
>   
> -				c->u.ibendport.port = le32_to_cpu(buf[1]);
> -
>   				rc = context_read_and_validate(&c->context[0],
>   							       p,
>   							       fp);
> @@ -3105,6 +3112,7 @@ static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
>   {
>   	unsigned int i, j, rc;
>   	size_t nel, len;
> +	__be64 prefixbuf[1];
>   	__le32 buf[3];
>   	u32 nodebuf[8];
>   	struct ocontext *c;
> @@ -3192,12 +3200,17 @@ static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
>   					return rc;
>   				break;
>   			case OCON_IBPKEY:
> -				*((__be64 *)nodebuf) = cpu_to_be64(c->u.ibpkey.subnet_prefix);
> +				/* subnet_prefix is in CPU order */
> +				prefixbuf[0] = cpu_to_be64(c->u.ibpkey.subnet_prefix);
>   
> -				nodebuf[2] = cpu_to_le32(c->u.ibpkey.low_pkey);
> -				nodebuf[3] = cpu_to_le32(c->u.ibpkey.high_pkey);
> +				rc = put_entry(prefixbuf, sizeof(u64), 1, fp);
> +				if (rc)
> +					return rc;
> +
> +				buf[0] = cpu_to_le32(c->u.ibpkey.low_pkey);
> +				buf[1] = cpu_to_le32(c->u.ibpkey.high_pkey);
>   
> -				rc = put_entry(nodebuf, sizeof(u32), 4, fp);
> +				rc = put_entry(buf, sizeof(u32), 2, fp);
>   				if (rc)
>   					return rc;
>   				rc = context_write(p, &c->context[0], fp);
>
William Roberts Oct. 17, 2018, 10:09 p.m. UTC | #2 
On Wed, Oct 17, 2018 at 7:19 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
>
> Do the LE conversions before doing the Infiniband-related range checks.
> The incorrect checks are otherwise causing a failure to load any policy
> with an ibendportcon rule on BE systems. This can be reproduced by
> running (on e.g. ppc64):
>
> cat >my_module.cil <<EOF
> (type test_ibendport_t)
> (roletype object_r test_ibendport_t)
> (ibendportcon mlx4_0 1 (system_u object_r test_ibendport_t ((s0) (s0))))
> EOF
> semodule -i my_module.cil
>
> Also, fix loading/storing the 64-bit subnet prefix for OCON_IBPKEY to
> use a correctly aligned buffer.
>
> Finally, do not use the 'nodebuf' (u32) buffer where 'buf' (__le32)
> should be used instead.
>
> Tested internally on a ppc64 machine with a RHEL 7 kernel with this
> patch applied.
>
> Cc: Daniel Jurgens <danielj@mellanox.com>
> Cc: Eli Cohen <eli@mellanox.com>
> Cc: James Morris <jmorris@namei.org>
> Cc: Doug Ledford <dledford@redhat.com>
> Cc: <stable@vger.kernel.org> # 4.13+
> Fixes: a806f7a1616f ("selinux: Create policydb version for Infiniband support")
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> ---
>  security/selinux/ss/policydb.c | 41 ++++++++++++++++++++++------------
>  1 file changed, 27 insertions(+), 14 deletions(-)
>
> Changes in v3:
>  - use separate buffer for the 64-bit subnet_prefix
>  - add comments on the byte ordering of subnet_prefix
>  - deduplicate the le32_to_cpu() calls from checks
>
> Changes in v2:
>  - add reproducer to commit message
>  - update e-mail address of James Morris
>  - better Cc also the old SELinux ML
>
> diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
> index f4eadd3f7350..b9029491869b 100644
> --- a/security/selinux/ss/policydb.c
> +++ b/security/selinux/ss/policydb.c
> @@ -2108,6 +2108,7 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
>  {
>         int i, j, rc;
>         u32 nel, len;
> +       __be64 prefixbuf[1];
>         __le32 buf[3];
>         struct ocontext *l, *c;
>         u32 nodebuf[8];
> @@ -2218,21 +2219,26 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
>                                 break;
>                         }
>                         case OCON_IBPKEY:
> -                               rc = next_entry(nodebuf, fp, sizeof(u32) * 4);
> +                               rc = next_entry(prefixbuf, fp, sizeof(u64));
>                                 if (rc)
>                                         goto out;
>
> -                               c->u.ibpkey.subnet_prefix = be64_to_cpu(*((__be64 *)nodebuf));
> +                               /* we need to have subnet_prefix in CPU order */
> +                               c->u.ibpkey.subnet_prefix = be64_to_cpu(prefixbuf[0]);
>
> -                               if (nodebuf[2] > 0xffff ||
> -                                   nodebuf[3] > 0xffff) {
> +                               rc = next_entry(buf, fp, sizeof(u32) * 2);
> +                               if (rc)
> +                                       goto out;
> +
> +                               c->u.ibpkey.low_pkey  = le32_to_cpu(buf[0]);
> +                               c->u.ibpkey.high_pkey = le32_to_cpu(buf[1]);

We noticed this in the coresponding user space patch. Assigning 32 to
16 truncates the values and thus
the conditionals below are always false.

struct {
  u64 subnet_prefix;
  u16 low_pkey;   <-- u16
  u16 high_pkey;  <-- u16
} ibpkey;

I figured I would comment just to make sure folks following one patch
and not the other are
informed. You'll need to respin a v4 and asign to a u32 intermediate,
range check and the assign.

> +
> +                               if (c->u.ibpkey.low_pkey  > 0xffff ||
> +                                   c->u.ibpkey.high_pkey > 0xffff) {
>                                         rc = -EINVAL;
>                                         goto out;
>                                 }
>
> -                               c->u.ibpkey.low_pkey = le32_to_cpu(nodebuf[2]);
> -                               c->u.ibpkey.high_pkey = le32_to_cpu(nodebuf[3]);
> -
>                                 rc = context_read_and_validate(&c->context[0],
>                                                                p,
>                                                                fp);
> @@ -2249,13 +2255,14 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
>                                 if (rc)
>                                         goto out;
>
> -                               if (buf[1] > 0xff || buf[1] == 0) {
> +                               c->u.ibendport.port = le32_to_cpu(buf[1]);
> +
> +                               if (c->u.ibendport.port > 0xff ||
> +                                   c->u.ibendport.port == 0) {
>                                         rc = -EINVAL;
>                                         goto out;
>                                 }
>
> -                               c->u.ibendport.port = le32_to_cpu(buf[1]);
> -
>                                 rc = context_read_and_validate(&c->context[0],
>                                                                p,
>                                                                fp);
> @@ -3105,6 +3112,7 @@ static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
>  {
>         unsigned int i, j, rc;
>         size_t nel, len;
> +       __be64 prefixbuf[1];
>         __le32 buf[3];
>         u32 nodebuf[8];
>         struct ocontext *c;
> @@ -3192,12 +3200,17 @@ static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
>                                         return rc;
>                                 break;
>                         case OCON_IBPKEY:
> -                               *((__be64 *)nodebuf) = cpu_to_be64(c->u.ibpkey.subnet_prefix);
> +                               /* subnet_prefix is in CPU order */
> +                               prefixbuf[0] = cpu_to_be64(c->u.ibpkey.subnet_prefix);
>
> -                               nodebuf[2] = cpu_to_le32(c->u.ibpkey.low_pkey);
> -                               nodebuf[3] = cpu_to_le32(c->u.ibpkey.high_pkey);
> +                               rc = put_entry(prefixbuf, sizeof(u64), 1, fp);
> +                               if (rc)
> +                                       return rc;
> +
> +                               buf[0] = cpu_to_le32(c->u.ibpkey.low_pkey);
> +                               buf[1] = cpu_to_le32(c->u.ibpkey.high_pkey);
>
> -                               rc = put_entry(nodebuf, sizeof(u32), 4, fp);
> +                               rc = put_entry(buf, sizeof(u32), 2, fp);
>                                 if (rc)
>                                         return rc;
>                                 rc = context_write(p, &c->context[0], fp);
> --
> 2.17.2
>
> _______________________________________________
> Selinux mailing list
> Selinux@tycho.nsa.gov
> To unsubscribe, send email to Selinux-leave@tycho.nsa.gov.
> To get help, send an email containing "help" to Selinux-request@tycho.nsa.gov.
diff mbox series

Patch

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index f4eadd3f7350..b9029491869b 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -2108,6 +2108,7 @@  static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
 {
 	int i, j, rc;
 	u32 nel, len;
+	__be64 prefixbuf[1];
 	__le32 buf[3];
 	struct ocontext *l, *c;
 	u32 nodebuf[8];
@@ -2218,21 +2219,26 @@  static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
 				break;
 			}
 			case OCON_IBPKEY:
-				rc = next_entry(nodebuf, fp, sizeof(u32) * 4);
+				rc = next_entry(prefixbuf, fp, sizeof(u64));
 				if (rc)
 					goto out;
 
-				c->u.ibpkey.subnet_prefix = be64_to_cpu(*((__be64 *)nodebuf));
+				/* we need to have subnet_prefix in CPU order */
+				c->u.ibpkey.subnet_prefix = be64_to_cpu(prefixbuf[0]);
 
-				if (nodebuf[2] > 0xffff ||
-				    nodebuf[3] > 0xffff) {
+				rc = next_entry(buf, fp, sizeof(u32) * 2);
+				if (rc)
+					goto out;
+
+				c->u.ibpkey.low_pkey  = le32_to_cpu(buf[0]);
+				c->u.ibpkey.high_pkey = le32_to_cpu(buf[1]);
+
+				if (c->u.ibpkey.low_pkey  > 0xffff ||
+				    c->u.ibpkey.high_pkey > 0xffff) {
 					rc = -EINVAL;
 					goto out;
 				}
 
-				c->u.ibpkey.low_pkey = le32_to_cpu(nodebuf[2]);
-				c->u.ibpkey.high_pkey = le32_to_cpu(nodebuf[3]);
-
 				rc = context_read_and_validate(&c->context[0],
 							       p,
 							       fp);
@@ -2249,13 +2255,14 @@  static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
 				if (rc)
 					goto out;
 
-				if (buf[1] > 0xff || buf[1] == 0) {
+				c->u.ibendport.port = le32_to_cpu(buf[1]);
+
+				if (c->u.ibendport.port > 0xff ||
+				    c->u.ibendport.port == 0) {
 					rc = -EINVAL;
 					goto out;
 				}
 
-				c->u.ibendport.port = le32_to_cpu(buf[1]);
-
 				rc = context_read_and_validate(&c->context[0],
 							       p,
 							       fp);
@@ -3105,6 +3112,7 @@  static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
 {
 	unsigned int i, j, rc;
 	size_t nel, len;
+	__be64 prefixbuf[1];
 	__le32 buf[3];
 	u32 nodebuf[8];
 	struct ocontext *c;
@@ -3192,12 +3200,17 @@  static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
 					return rc;
 				break;
 			case OCON_IBPKEY:
-				*((__be64 *)nodebuf) = cpu_to_be64(c->u.ibpkey.subnet_prefix);
+				/* subnet_prefix is in CPU order */
+				prefixbuf[0] = cpu_to_be64(c->u.ibpkey.subnet_prefix);
 
-				nodebuf[2] = cpu_to_le32(c->u.ibpkey.low_pkey);
-				nodebuf[3] = cpu_to_le32(c->u.ibpkey.high_pkey);
+				rc = put_entry(prefixbuf, sizeof(u64), 1, fp);
+				if (rc)
+					return rc;
+
+				buf[0] = cpu_to_le32(c->u.ibpkey.low_pkey);
+				buf[1] = cpu_to_le32(c->u.ibpkey.high_pkey);
 
-				rc = put_entry(nodebuf, sizeof(u32), 4, fp);
+				rc = put_entry(buf, sizeof(u32), 2, fp);
 				if (rc)
 					return rc;
 				rc = context_write(p, &c->context[0], fp);