cifs: fix path comparison and hash calc

Fix cache lookup and hash calculations when handling paths with
different cases.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara 2021-06-04 19:25:31 -03:00 committed by Steve French
parent c870a8e70e
commit 42caeba713

View file

@ -424,12 +424,24 @@ int dfs_cache_init(void)
return rc;
}
static inline unsigned int cache_entry_hash(const void *data, int size)
static int cache_entry_hash(const void *data, int size, unsigned int *hash)
{
unsigned int h;
int i, clen;
const unsigned char *s = data;
wchar_t c;
unsigned int h = 0;
h = jhash(data, size, 0);
return h & (CACHE_HTABLE_SIZE - 1);
for (i = 0; i < size; i += clen) {
clen = cache_cp->char2uni(&s[i], size - i, &c);
if (unlikely(clen < 0)) {
cifs_dbg(VFS, "%s: can't convert char\n", __func__);
return clen;
}
c = cifs_toupper(c);
h = jhash(&c, sizeof(c), h);
}
*hash = h % CACHE_HTABLE_SIZE;
return 0;
}
/* Return target hint of a DFS cache entry */
@ -511,9 +523,7 @@ static int copy_ref_data(const struct dfs_info3_param *refs, int numrefs,
}
/* Allocate a new cache entry */
static struct cache_entry *alloc_cache_entry(const char *path,
const struct dfs_info3_param *refs,
int numrefs)
static struct cache_entry *alloc_cache_entry(struct dfs_info3_param *refs, int numrefs)
{
struct cache_entry *ce;
int rc;
@ -522,11 +532,9 @@ static struct cache_entry *alloc_cache_entry(const char *path,
if (!ce)
return ERR_PTR(-ENOMEM);
ce->path = kstrdup(path, GFP_KERNEL);
if (!ce->path) {
kmem_cache_free(cache_slab, ce);
return ERR_PTR(-ENOMEM);
}
ce->path = refs[0].path_name;
refs[0].path_name = NULL;
INIT_HLIST_NODE(&ce->hlist);
INIT_LIST_HEAD(&ce->tlist);
@ -568,12 +576,18 @@ static void remove_oldest_entry_locked(void)
}
/* Add a new DFS cache entry */
static int add_cache_entry_locked(const char *path, unsigned int hash,
struct dfs_info3_param *refs, int numrefs)
static int add_cache_entry_locked(struct dfs_info3_param *refs, int numrefs)
{
int rc;
struct cache_entry *ce;
unsigned int hash;
ce = alloc_cache_entry(path, refs, numrefs);
convert_delimiter(refs[0].path_name, '\\');
rc = cache_entry_hash(refs[0].path_name, strlen(refs[0].path_name), &hash);
if (rc)
return rc;
ce = alloc_cache_entry(refs, numrefs);
if (IS_ERR(ce))
return PTR_ERR(ce);
@ -593,57 +607,69 @@ static int add_cache_entry_locked(const char *path, unsigned int hash,
return 0;
}
static struct cache_entry *__lookup_cache_entry(const char *path)
/* Check if two DFS paths are equal. @s1 and @s2 are expected to be in @cache_cp's charset */
static bool dfs_path_equal(const char *s1, int len1, const char *s2, int len2)
{
int i, l1, l2;
wchar_t c1, c2;
if (len1 != len2)
return false;
for (i = 0; i < len1; i += l1) {
l1 = cache_cp->char2uni(&s1[i], len1 - i, &c1);
l2 = cache_cp->char2uni(&s2[i], len2 - i, &c2);
if (unlikely(l1 < 0 && l2 < 0)) {
if (s1[i] != s2[i])
return false;
l1 = 1;
continue;
}
if (l1 != l2)
return false;
if (cifs_toupper(c1) != cifs_toupper(c2))
return false;
}
return true;
}
static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int hash, int len)
{
struct cache_entry *ce;
unsigned int h;
bool found = false;
h = cache_entry_hash(path, strlen(path));
hlist_for_each_entry(ce, &cache_htable[h], hlist) {
if (!strcasecmp(path, ce->path)) {
found = true;
hlist_for_each_entry(ce, &cache_htable[hash], hlist) {
if (dfs_path_equal(ce->path, strlen(ce->path), path, len)) {
dump_ce(ce);
break;
return ce;
}
}
if (!found)
ce = ERR_PTR(-ENOENT);
return ce;
return ERR_PTR(-EEXIST);
}
/*
* Find a DFS cache entry in hash table and optionally check prefix path against
* @path.
* Use whole path components in the match.
* Must be called with htable_rw_lock held.
* Find a DFS cache entry in hash table and optionally check prefix path against normalized @path.
*
* Return ERR_PTR(-ENOENT) if the entry is not found.
* Use whole path components in the match. Must be called with htable_rw_lock held.
*
* Return ERR_PTR(-EEXIST) if the entry is not found.
*/
static struct cache_entry *lookup_cache_entry(const char *path, unsigned int *hash)
static struct cache_entry *lookup_cache_entry(const char *path)
{
struct cache_entry *ce = ERR_PTR(-ENOENT);
unsigned int h;
struct cache_entry *ce;
int cnt = 0;
char *npath;
char *s, *e;
char sep;
const char *s = path, *e;
char sep = *s;
unsigned int hash;
int rc;
npath = kstrdup(path, GFP_KERNEL);
if (!npath)
return ERR_PTR(-ENOMEM);
s = npath;
sep = *npath;
while ((s = strchr(s, sep)) && ++cnt < 3)
s++;
if (cnt < 3) {
h = cache_entry_hash(path, strlen(path));
ce = __lookup_cache_entry(path);
goto out;
rc = cache_entry_hash(path, strlen(path), &hash);
if (rc)
return ERR_PTR(rc);
return __lookup_cache_entry(path, hash, strlen(path));
}
/*
* Handle paths that have more than two path components and are a complete prefix of the DFS
@ -651,36 +677,29 @@ static struct cache_entry *lookup_cache_entry(const char *path, unsigned int *ha
*
* See MS-DFSC 3.2.5.5 "Receiving a Root Referral Request or Link Referral Request".
*/
h = cache_entry_hash(npath, strlen(npath));
e = npath + strlen(npath) - 1;
e = path + strlen(path) - 1;
while (e > s) {
char tmp;
int len;
/* skip separators */
while (e > s && *e == sep)
e--;
if (e == s)
goto out;
tmp = *(e+1);
*(e+1) = 0;
ce = __lookup_cache_entry(npath);
if (!IS_ERR(ce)) {
h = cache_entry_hash(npath, strlen(npath));
break;
}
*(e+1) = tmp;
len = e + 1 - path;
rc = cache_entry_hash(path, len, &hash);
if (rc)
return ERR_PTR(rc);
ce = __lookup_cache_entry(path, hash, len);
if (!IS_ERR(ce))
return ce;
/* backward until separator */
while (e > s && *e != sep)
e--;
}
out:
if (hash)
*hash = h;
kfree(npath);
return ce;
return ERR_PTR(-EEXIST);
}
/**
@ -706,7 +725,7 @@ static int update_cache_entry_locked(const char *path, const struct dfs_info3_pa
struct cache_entry *ce;
char *s, *th = NULL;
ce = lookup_cache_entry(path, NULL);
ce = lookup_cache_entry(path);
if (IS_ERR(ce))
return PTR_ERR(ce);
@ -756,7 +775,6 @@ static int get_dfs_referral(const unsigned int xid, struct cifs_ses *ses, const
static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, const char *path)
{
int rc;
unsigned int hash;
struct cache_entry *ce;
struct dfs_info3_param *refs = NULL;
int numrefs = 0;
@ -766,7 +784,7 @@ static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, cons
down_write(&htable_rw_lock);
ce = lookup_cache_entry(path, &hash);
ce = lookup_cache_entry(path);
if (!IS_ERR(ce)) {
if (!cache_entry_expired(ce)) {
dump_ce(ce);
@ -797,7 +815,7 @@ static int cache_refresh_path(const unsigned int xid, struct cifs_ses *ses, cons
remove_oldest_entry_locked();
}
rc = add_cache_entry_locked(path, hash, refs, numrefs);
rc = add_cache_entry_locked(refs, numrefs);
if (!rc)
atomic_inc(&cache_count);
@ -929,7 +947,7 @@ int dfs_cache_find(const unsigned int xid, struct cifs_ses *ses, const struct nl
down_read(&htable_rw_lock);
ce = lookup_cache_entry(npath, NULL);
ce = lookup_cache_entry(npath);
if (IS_ERR(ce)) {
up_read(&htable_rw_lock);
rc = PTR_ERR(ce);
@ -976,7 +994,7 @@ int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
down_read(&htable_rw_lock);
ce = lookup_cache_entry(path, NULL);
ce = lookup_cache_entry(path);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out_unlock;
@ -1033,7 +1051,7 @@ int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses,
down_write(&htable_rw_lock);
ce = lookup_cache_entry(npath, NULL);
ce = lookup_cache_entry(npath);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out_unlock;
@ -1087,7 +1105,7 @@ int dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt_
down_write(&htable_rw_lock);
ce = lookup_cache_entry(path, NULL);
ce = lookup_cache_entry(path);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out_unlock;
@ -1136,7 +1154,7 @@ int dfs_cache_get_tgt_referral(const char *path, const struct dfs_cache_tgt_iter
down_read(&htable_rw_lock);
ce = lookup_cache_entry(path, NULL);
ce = lookup_cache_entry(path);
if (IS_ERR(ce)) {
rc = PTR_ERR(ce);
goto out_unlock;