[PATCH v3] xen/xsm: Make p->policyvers be a local variable (ver) to shut up GCC 5.1.1 warnings.

[PATCH v3] xen/xsm: Make p->policyvers be a local variable (ver) to shut up GCC 5.1.1 warnings.

[Konrad Rzeszutek Wilk]

policydb.c: In function ‘user_read’:
policydb.c:1443:26: error: ‘buf[2]’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
         usrdatum->bounds = le32_to_cpu(buf[2]);
                          ^
cc1: all warnings being treated as errors

Which (as Andrew mentioned) is because GCC cannot assume
that 'p->policyvers' has the same value between checks.

We make it local, optimize the name to 'ver' and the warnings go away.
We also update another call site with this modification to
make it more inline with the rest of the functions.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 xen/xsm/flask/ss/policydb.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/xen/xsm/flask/ss/policydb.c b/xen/xsm/flask/ss/policydb.c
index a1060b1..eebfe9c 100644
--- a/xen/xsm/flask/ss/policydb.c
+++ b/xen/xsm/flask/ss/policydb.c
@@ -1258,6 +1258,7 @@ static int role_read(struct policydb *p, struct hashtab *h, void *fp)
     int rc;
     __le32 buf[3];
     u32 len;
+    u32 ver = p->policyvers;
 
     role = xzalloc(struct role_datum);
     if ( !role )
@@ -1266,7 +1267,7 @@ static int role_read(struct policydb *p, struct hashtab *h, void *fp)
         goto out;
     }
 
-    if ( p->policyvers >= POLICYDB_VERSION_BOUNDARY )
+    if ( ver >= POLICYDB_VERSION_BOUNDARY )
         rc = next_entry(buf, fp, sizeof(buf[0]) * 3);
     else
         rc = next_entry(buf, fp, sizeof(buf[0]) * 2);
@@ -1276,7 +1277,7 @@ static int role_read(struct policydb *p, struct hashtab *h, void *fp)
 
     len = le32_to_cpu(buf[0]);
     role->value = le32_to_cpu(buf[1]);
-    if ( p->policyvers >= POLICYDB_VERSION_BOUNDARY )
+    if ( ver >= POLICYDB_VERSION_BOUNDARY )
         role->bounds = le32_to_cpu(buf[2]);
 
     key = xmalloc_array(char, len + 1);
@@ -1328,6 +1329,7 @@ static int type_read(struct policydb *p, struct hashtab *h, void *fp)
     int rc;
     __le32 buf[4];
     u32 len;
+    u32 ver = p->policyvers;
 
     typdatum = xzalloc(struct type_datum);
     if ( !typdatum )
@@ -1336,7 +1338,7 @@ static int type_read(struct policydb *p, struct hashtab *h, void *fp)
         return rc;
     }
 
-    if ( p->policyvers >= POLICYDB_VERSION_BOUNDARY )
+    if ( ver >= POLICYDB_VERSION_BOUNDARY )
         rc = next_entry(buf, fp, sizeof(buf[0]) * 4);
     else
         rc = next_entry(buf, fp, sizeof(buf[0]) * 3);
@@ -1346,7 +1348,7 @@ static int type_read(struct policydb *p, struct hashtab *h, void *fp)
 
     len = le32_to_cpu(buf[0]);
     typdatum->value = le32_to_cpu(buf[1]);
-    if ( p->policyvers >= POLICYDB_VERSION_BOUNDARY )
+    if ( ver >= POLICYDB_VERSION_BOUNDARY )
     {
         u32 prop = le32_to_cpu(buf[2]);
 
@@ -1421,6 +1423,7 @@ static int user_read(struct policydb *p, struct hashtab *h, void *fp)
     int rc;
     __le32 buf[3];
     u32 len;
+    u32 ver = p->policyvers;
 
     usrdatum = xzalloc(struct user_datum);
     if ( !usrdatum )
@@ -1429,7 +1432,7 @@ static int user_read(struct policydb *p, struct hashtab *h, void *fp)
         goto out;
     }
 
-    if ( p->policyvers >= POLICYDB_VERSION_BOUNDARY )
+    if ( ver >= POLICYDB_VERSION_BOUNDARY )
         rc = next_entry(buf, fp, sizeof(buf[0]) * 3);
     else
         rc = next_entry(buf, fp, sizeof(buf[0]) * 2);
@@ -1439,7 +1442,7 @@ static int user_read(struct policydb *p, struct hashtab *h, void *fp)
 
     len = le32_to_cpu(buf[0]);
     usrdatum->value = le32_to_cpu(buf[1]);
-    if ( p->policyvers >= POLICYDB_VERSION_BOUNDARY )
+    if ( ver >= POLICYDB_VERSION_BOUNDARY )
         usrdatum->bounds = le32_to_cpu(buf[2]);
 
     key = xmalloc_array(char, len + 1);
@@ -1457,7 +1460,7 @@ static int user_read(struct policydb *p, struct hashtab *h, void *fp)
     if ( rc )
         goto bad;
 
-    if ( p->policyvers >= POLICYDB_VERSION_MLS )
+    if ( ver >= POLICYDB_VERSION_MLS )
     {
         rc = mls_read_range_helper(&usrdatum->range, fp);
         if ( rc )
-- 
2.4.3


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Re: [PATCH v3] xen/xsm: Make p->policyvers be a local variable (ver) to shut up GCC 5.1.1 warnings.

[Daniel De Graaf]

On 16/09/15 15:57, Konrad Rzeszutek Wilk wrote:
> policydb.c: In function ‘user_read’:
> policydb.c:1443:26: error: ‘buf[2]’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>           usrdatum->bounds = le32_to_cpu(buf[2]);
>                            ^
> cc1: all warnings being treated as errors
>
> Which (as Andrew mentioned) is because GCC cannot assume
> that 'p->policyvers' has the same value between checks.
>
> We make it local, optimize the name to 'ver' and the warnings go away.
> We also update another call site with this modification to
> make it more inline with the rest of the functions.
>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>

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