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ceph: fix three bugs, two in ceph_vxattrcb_file_layout()

PATCH In review Alex Elder 2 participants 2 messages Mar 12, 2012 – Mar 13, 2012 Ceph client

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Alex Elder

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PATCH 1/1 ceph: fix three bugs, two in ceph_vxattrcb_file_layout()

In ceph_vxattrcb_file_layout(), there is a check to determine whether a preferred PG should be formatted into the output buffer. That check assumes that a preferred PG number of 0 indicates "no preference," but that is wrong. No preference is indicated by a negative (specifically, -1) PG number.

In addition, if that condition yields true, the preferred value is formatted into a sized buffer, but the size consumed by the earlier snprintf() call is not accounted for, opening up the possibilty of a buffer overrun.

Finally, in ceph_vxattrcb_dir_rctime() where the nanoseconds part of the time displayed did not include leading 0's, which led to erroneous (sub-second portion of) time values being shown.

This fixes these three issues:

    http://tracker.newdream.net/issues/2155
    http://tracker.newdream.net/issues/2156
    http://tracker.newdream.net/issues/2157
Signed-off-by Alex Elder <[email protected]>
---
 fs/ceph/xattr.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)
fs/ceph/xattr.c +0 -0
index 18df51e..715cfc6 100644
@@ -79,7 +79,7 @@ static size_t ceph_vxattrcb_dir_rbytes(struct ceph_inode_info *ci, char *val,
 static size_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci,

char *val,
size_t size)
{
- return snprintf(val, size, "%ld.%ld", (long)ci->i_rctime.tv_sec,
+ return snprintf(val, size, "%ld.09%ld", (long)ci->i_rctime.tv_sec,
(long)ci->i_rctime.tv_nsec);
}

@@ -118,10 +118,15 @@ static size_t ceph_vxattrcb_file_layout(struct ceph_inode_info *ci, char *val,
(unsigned long long)ceph_file_layout_su(ci->i_layout),
(unsigned long long)ceph_file_layout_stripe_count(ci->i_layout), (unsigned long long)ceph_file_layout_object_size(ci->i_layout));
- if (ceph_file_layout_pg_preferred(ci->i_layout))
- ret += snprintf(val + ret, size, "preferred_osd=%lld\n",
+
+ if (ceph_file_layout_pg_preferred(ci->i_layout) >= 0) {
+ val += ret;
+ size -= ret;
+ ret += snprintf(val, size, "preferred_osd=%lld\n",
(unsigned long long)ceph_file_layout_pg_preferred(
ci->i_layout));
+ }
+
return ret;
}

Signature · 1 line
1.7.5.4
Reviewed-by on v1 1/1
#1 lore raw
Reviewed-by Sage Weil <[email protected]>
Quoted 69 lines · Alex Elder

In ceph_vxattrcb_file_layout(), there is a check to determine whether a preferred PG should be formatted into the output buffer. That check assumes that a preferred PG number of 0 indicates "no preference," but that is wrong. No preference is indicated by a negative (specifically, -1) PG number.

In addition, if that condition yields true, the preferred value is formatted into a sized buffer, but the size consumed by the earlier snprintf() call is not accounted for, opening up the possibilty of a buffer overrun.

Finally, in ceph_vxattrcb_dir_rctime() where the nanoseconds part of the time displayed did not include leading 0's, which led to erroneous (sub-second portion of) time values being shown.

This fixes these three issues:

    http://tracker.newdream.net/issues/2155
    http://tracker.newdream.net/issues/2156
    http://tracker.newdream.net/issues/2157
Signed-off-by Alex Elder <[email protected]>
---
 fs/ceph/xattr.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)
fs/ceph/xattr.c +8 -3
index 18df51e..715cfc6 100644
@@ -79,7 +79,7 @@ static size_t ceph_vxattrcb_dir_rbytes(struct
 ceph_inode_info *ci, char *val,
 static size_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci, char *val,
 				       size_t size)
 {
-	return snprintf(val, size, "%ld.%ld", (long)ci->i_rctime.tv_sec,
+	return snprintf(val, size, "%ld.09%ld", (long)ci->i_rctime.tv_sec,
 			(long)ci->i_rctime.tv_nsec);
 }

@@ -118,10 +118,15 @@ static size_t ceph_vxattrcb_file_layout(struct
 ceph_inode_info *ci, char *val,
 		(unsigned long long)ceph_file_layout_su(ci->i_layout),
 		(unsigned long
 long)ceph_file_layout_stripe_count(ci->i_layout),
 		(unsigned long
 long)ceph_file_layout_object_size(ci->i_layout));
-	if (ceph_file_layout_pg_preferred(ci->i_layout))
-		ret += snprintf(val + ret, size, "preferred_osd=%lld\n",
+
+	if (ceph_file_layout_pg_preferred(ci->i_layout) >= 0) {
+		val += ret;
+		size -= ret;
+		ret += snprintf(val, size, "preferred_osd=%lld\n",
 			    (unsigned long long)ceph_file_layout_pg_preferred(
 				    ci->i_layout));
+	}
+

return ret;
}

Signature · 6 lines
1.7.5.4

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