* [PATCH] CacheFiles: Fix memory leak in cachefiles_check_auxdata error paths
@ 2013-09-10 14:19 Josh Boyer
0 siblings, 0 replies; 2+ messages in thread
From: Josh Boyer @ 2013-09-10 14:19 UTC (permalink / raw)
To: David Howells; +Cc: linux-cachefs, linux-kernel
We kmalloc auxbuf but fail to kfree it if we get errors in various places.
Rework the error paths to avoid the resource leak.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
---
fs/cachefiles/xattr.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
index 34c88b8..f929ab6 100644
--- a/fs/cachefiles/xattr.c
+++ b/fs/cachefiles/xattr.c
@@ -176,20 +176,28 @@ int cachefiles_check_auxdata(struct cachefiles_object *object)
auxbuf->len = vfs_getxattr(dentry, cachefiles_xattr_cache,
&auxbuf->type, 512 + 1);
- if (auxbuf->len < 1)
- return -ESTALE;
+ if (auxbuf->len < 1) {
+ ret = -ESTALE;
+ goto error;
+ }
- if (auxbuf->type != object->fscache.cookie->def->type)
- return -ESTALE;
+ if (auxbuf->type != object->fscache.cookie->def->type) {
+ ret = -ESTALE;
+ goto error;
+ }
dlen = auxbuf->len - 1;
ret = fscache_check_aux(&object->fscache, &auxbuf->data, dlen);
- kfree(auxbuf);
- if (ret != FSCACHE_CHECKAUX_OKAY)
- return -ESTALE;
+ if (ret != FSCACHE_CHECKAUX_OKAY) {
+ ret = -ESTALE;
+ goto error;
+ }
- return 0;
+ ret = 0;
+error:
+ kfree(auxbuf);
+ return ret;
}
/*
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH] CacheFiles: Fix memory leak in cachefiles_check_auxdata error paths
@ 2013-09-11 15:38 David Howells
0 siblings, 0 replies; 2+ messages in thread
From: David Howells @ 2013-09-11 15:38 UTC (permalink / raw)
To: milosz; +Cc: ceph-devel, linux-cachefs, linux-kernel, Hongyi Jia, Josh Boyer
From: Josh Boyer <jwboyer@redhat.com>
In cachefiles_check_auxdata(), we allocate auxbuf but fail to free it if we get
determine there's an error or that the data is stale.
Further, assigning the output of vfs_getxattr() to auxbuf->len gives problems
with checking for errors as auxbuf->len is a u16. We don't actually need to
set auxbuf->len, so keep the length in a variable for now. We shouldn't need
to check the upper limit of the buffer as an overflow there should be
indicated by -ERANGE.
Whilst we're at it, fscache_check_aux() returns an enum value, not an int, so
assign it to an appropriately typed variable rather than to ret.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hongyi Jia <jiayisuse@gmail.com>
cc: Milosz Tanski <milosz@adfin.com>
---
fs/cachefiles/xattr.c | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)
diff --git a/fs/cachefiles/xattr.c b/fs/cachefiles/xattr.c
index 34c88b8..12b0eef 100644
--- a/fs/cachefiles/xattr.c
+++ b/fs/cachefiles/xattr.c
@@ -162,8 +162,9 @@ int cachefiles_update_object_xattr(struct cachefiles_object *object,
int cachefiles_check_auxdata(struct cachefiles_object *object)
{
struct cachefiles_xattr *auxbuf;
+ enum fscache_checkaux validity;
struct dentry *dentry = object->dentry;
- unsigned int dlen;
+ ssize_t xlen;
int ret;
ASSERT(dentry);
@@ -174,22 +175,22 @@ int cachefiles_check_auxdata(struct cachefiles_object *object)
if (!auxbuf)
return -ENOMEM;
- auxbuf->len = vfs_getxattr(dentry, cachefiles_xattr_cache,
- &auxbuf->type, 512 + 1);
- if (auxbuf->len < 1)
- return -ESTALE;
-
- if (auxbuf->type != object->fscache.cookie->def->type)
- return -ESTALE;
+ xlen = vfs_getxattr(dentry, cachefiles_xattr_cache,
+ &auxbuf->type, 512 + 1);
+ ret = -ESTALE;
+ if (xlen < 1 ||
+ auxbuf->type != object->fscache.cookie->def->type)
+ goto error;
- dlen = auxbuf->len - 1;
- ret = fscache_check_aux(&object->fscache, &auxbuf->data, dlen);
+ xlen--;
+ validity = fscache_check_aux(&object->fscache, &auxbuf->data, xlen);
+ if (validity != FSCACHE_CHECKAUX_OKAY)
+ goto error;
+ ret = 0;
+error:
kfree(auxbuf);
- if (ret != FSCACHE_CHECKAUX_OKAY)
- return -ESTALE;
-
- return 0;
+ return ret;
}
/*
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2013-09-10 14:19 [PATCH] CacheFiles: Fix memory leak in cachefiles_check_auxdata error paths Josh Boyer
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