Commit 42caeba7 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

cifs: fix path comparison and hash calc 



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

Signed-off-by: default avatarPaulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: default avatarAurelien Aptel <aaptel@suse.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent c870a8e7

fs/cifs/dfs_cache.c

+94 −76
Original line number Diff line number Diff line
@@ -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)

{

	struct cache_entry *ce;

	unsigned int h;

	bool found = false;

	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;

}



	h = cache_entry_hash(path, strlen(path));

static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int hash, int len)

{

	struct cache_entry *ce;



	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.

 *

 * Use whole path components in the match.  Must be called with htable_rw_lock held.

 *

 * Return ERR_PTR(-ENOENT) if the entry is not found.

 * 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;



	npath = kstrdup(path, GFP_KERNEL);

	if (!npath)

		return ERR_PTR(-ENOMEM);

	const char *s = path, *e;

	char sep = *s;

	unsigned int hash;

	int rc;



	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;