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Subject[PATCH 2/4] selinux: Adjust jump targets in ebitmap_read()
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From: Markus Elfring <elfring@users.sourceforge.net>
Date: Sun, 13 Aug 2017 15:21:43 +0200

Adjust jump targets so that the function implementation becomes smaller.

* Move an error message so that it is present only once here.

* Avoid another check for the local variable "rc" at the end.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
security/selinux/ss/ebitmap.c | 38 ++++++++++++++++++--------------------
1 file changed, 18 insertions(+), 20 deletions(-)

diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c
index ccf372db689c..03581d7ef817 100644
--- a/security/selinux/ss/ebitmap.c
+++ b/security/selinux/ss/ebitmap.c
@@ -350,21 +350,20 @@ int ebitmap_read(struct ebitmap *e, void *fp)
__le32 buf[3];
int rc, i;

- ebitmap_init(e);
-
rc = next_entry(buf, fp, sizeof buf);
if (rc < 0)
goto out;

- mapunit = le32_to_cpu(buf[0]);
+ ebitmap_init(e);
e->highbit = le32_to_cpu(buf[1]);
count = le32_to_cpu(buf[2]);
+ mapunit = le32_to_cpu(buf[0]);

if (mapunit != BITS_PER_U64) {
printk(KERN_ERR "SELinux: ebitmap: map size %u does not "
"match my size %zd (high bit was %d)\n",
mapunit, BITS_PER_U64, e->highbit);
- goto bad;
+ goto destroy_bitmap;
}

/* round up e->highbit */
@@ -377,27 +376,26 @@ int ebitmap_read(struct ebitmap *e, void *fp)
}

if (e->highbit && !count)
- goto bad;
+ goto destroy_bitmap;

for (i = 0; i < count; i++) {
rc = next_entry(&startbit, fp, sizeof(u32));
- if (rc < 0) {
- printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
- goto bad;
- }
+ if (rc)
+ goto report_truncated_map;
+
startbit = le32_to_cpu(startbit);

if (startbit & (mapunit - 1)) {
printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
"not a multiple of the map unit size (%u)\n",
startbit, mapunit);
- goto bad;
+ goto destroy_bitmap;
}
if (startbit > e->highbit - mapunit) {
printk(KERN_ERR "SELinux: ebitmap start bit (%d) is "
"beyond the end of the bitmap (%u)\n",
startbit, (e->highbit - mapunit));
- goto bad;
+ goto destroy_bitmap;
}

if (!n || startbit >= n->startbit + EBITMAP_SIZE) {
@@ -407,7 +405,7 @@ int ebitmap_read(struct ebitmap *e, void *fp)
printk(KERN_ERR
"SELinux: ebitmap: out of memory\n");
rc = -ENOMEM;
- goto bad;
+ goto destroy_bitmap;
}
/* round down */
tmp->startbit = startbit - (startbit % EBITMAP_SIZE);
@@ -420,14 +418,13 @@ int ebitmap_read(struct ebitmap *e, void *fp)
printk(KERN_ERR "SELinux: ebitmap: start bit %d"
" comes after start bit %d\n",
startbit, n->startbit);
- goto bad;
+ goto destroy_bitmap;
}

rc = next_entry(&map, fp, sizeof(u64));
- if (rc < 0) {
- printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
- goto bad;
- }
+ if (rc)
+ goto report_truncated_map;
+
map = le64_to_cpu(map);

index = (startbit - n->startbit) / EBITMAP_UNIT_SIZE;
@@ -438,9 +435,10 @@ int ebitmap_read(struct ebitmap *e, void *fp)
}
out:
return rc;
-bad:
- if (!rc)
- rc = -EINVAL;
+report_truncated_map:
+ printk(KERN_ERR "SELinux: ebitmap: truncated map\n");
+ rc = -EINVAL;
+destroy_bitmap:
ebitmap_destroy(e);
goto out;
}
--
2.14.0
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