[linux-cifs-client] [PATCH] cifs: add helper to simplify unicode to
NLS conversion and use it (try #2)
Suresh Jayaraman
sjayaraman at suse.de
Mon Apr 13 09:43:16 GMT 2009
Thanks for the excellent review comments. Have incorporated all of them
except the concern that whether "src" is null terminated or not. I think
it is not required as cifs_strfromUCS_le() takes care of the boundary
check. Please review the updated patch below.
Add helper to simplify unicode(UCS/UTF-16) to NLS conversion. The helper
function calculates the memory needed exactly instead of using size
assumptions and consolidates some common code in there.
Signed-off-by: Suresh Jayaraman <sjayaraman at suse.de>
---
fs/cifs/cifs_unicode.h | 28 ++++++++++++++++++++
fs/cifs/cifsproto.h | 2 +
fs/cifs/cifssmb.c | 31 ++++++++++++++++++++++
fs/cifs/connect.c | 67 +++++++++++++++++++----------------------------
fs/cifs/sess.c | 46 +++++++++++++++-----------------
5 files changed, 110 insertions(+), 64 deletions(-)
diff --git a/fs/cifs/cifs_unicode.h b/fs/cifs/cifs_unicode.h
index 14eb9a2..06a267b 100644
--- a/fs/cifs/cifs_unicode.h
+++ b/fs/cifs/cifs_unicode.h
@@ -159,6 +159,34 @@ UniStrnlen(const wchar_t *ucs1, int maxlen)
}
/*
+ * UniStrnlenBytes: Return the length of a NLS string in bytes. Also, populates
+ * 'nchars' with the length of string in 16 bit Unicode chars.
+ */
+static inline size_t
+UniStrnlenBytes(const wchar_t *str, int maxlen, int *nchars,
+ const struct nls_table *codepage)
+{
+ int nc;
+ size_t i = 0, nbytes = 0;
+ wchar_t uni = *str;
+ char buf[NLS_MAX_CHARSET_SIZE]; /* enough for one char at a time */
+
+ while (*str++ && maxlen) {
+ nc = codepage->uni2char(uni, buf, NLS_MAX_CHARSET_SIZE);
+ if (nc > 0)
+ nbytes += nc;
+ else
+ nbytes += 1; /* for '?' */
+ i++;
+ if (i >= maxlen)
+ break;
+ }
+ *nchars = i;
+
+ return nbytes;
+}
+
+/*
* UniStrncat: Concatenate length limited string
*/
static inline wchar_t *
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 4167716..d0861d7 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -383,4 +383,6 @@ extern int CIFSSMBSetPosixACL(const int xid, struct cifsTconInfo *tcon,
const struct nls_table *nls_codepage, int remap_special_chars);
extern int CIFSGetExtAttr(const int xid, struct cifsTconInfo *tcon,
const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
+extern int cifs_ucs_to_nls(char **dst, const char *src, const int maxlen,
+ int *plen, const struct nls_table *nls_codepage);
#endif /* _CIFSPROTO_H */
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index bc09c99..ca99d35 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -81,6 +81,37 @@ static struct {
#endif /* CONFIG_CIFS_WEAK_PW_HASH */
#endif /* CIFS_POSIX */
+
+/*
+ * Calculates, allocates memory and converts to a NLS string.
+ * Note: caller is responsible for freeing dst if function returned 0.
+ * returns:
+ * on success - 0
+ * on failure - errno
+ */
+int
+cifs_ucs_to_nls(char **dst, const char *src, const int maxlen, int *plen,
+ const struct nls_table *nls_codepage)
+{
+ size_t nbytes;
+
+ nbytes = UniStrnlenBytes((wchar_t *)src, maxlen, plen, nls_codepage);
+ *dst = kzalloc(nbytes + 2, GFP_KERNEL);
+ if (!*dst)
+ goto err_exit;
+
+ cifs_strfromUCS_le(*dst, (__le16 *)src, *plen, nls_codepage);
+ /* Assumes NLS string has always 1 byte NULL terminator
+ * BB Need to be fixed otherwise */
+ (*dst)[*plen] = 0;
+
+ return 0;
+
+err_exit:
+ cERROR(1, ("Failed to allocate buffer for string\n"));
+ return -ENOMEM;
+}
+
/* Allocates buffer into dst and copies smb string from src to it.
* caller is responsible for freeing dst if function returned 0.
* returns:
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 0de3b56..17a6ef4 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2667,39 +2667,29 @@ CIFSSessSetup(unsigned int xid, struct cifsSesInfo *ses,
remaining_words =
BCC(smb_buffer_response) / 2;
}
- len =
- UniStrnlen((wchar_t *) bcc_ptr,
- remaining_words - 1);
-/* We look for obvious messed up bcc or strings in response so we do not go off
- the end since (at least) WIN2K and Windows XP have a major bug in not null
- terminating last Unicode string in response */
- if (ses->serverOS)
- kfree(ses->serverOS);
- ses->serverOS = kzalloc(2 * (len + 1),
- GFP_KERNEL);
- if (ses->serverOS == NULL)
+ /* Win2K and Windows XP seem to have a major bug
+ * in not null terminating last Unicode string
+ * in response */
+ kfree(ses->serverOS);
+ rc = cifs_ucs_to_nls(&(ses->serverOS), bcc_ptr,
+ remaining_words - 1, &len,
+ nls_codepage);
+ if (rc)
goto sesssetup_nomem;
- cifs_strfromUCS_le(ses->serverOS,
- (__le16 *)bcc_ptr,
- len, nls_codepage);
bcc_ptr += 2 * (len + 1);
remaining_words -= len + 1;
- ses->serverOS[2 * len] = 0;
- ses->serverOS[1 + (2 * len)] = 0;
if (remaining_words > 0) {
- len = UniStrnlen((wchar_t *)bcc_ptr,
- remaining_words-1);
+ /* Win2K and Windows XP seem to have a
+ * major bug in not null terminating
+ * last Unicode string in response */
kfree(ses->serverNOS);
- ses->serverNOS = kzalloc(2 * (len + 1),
- GFP_KERNEL);
- if (ses->serverNOS == NULL)
+ rc = cifs_ucs_to_nls(&(ses->serverNOS),
+ bcc_ptr,
+ remaining_words - 1,
+ &len, nls_codepage);
+ if (rc)
goto sesssetup_nomem;
- cifs_strfromUCS_le(ses->serverNOS,
- (__le16 *)bcc_ptr,
- len, nls_codepage);
bcc_ptr += 2 * (len + 1);
- ses->serverNOS[2 * len] = 0;
- ses->serverNOS[1 + (2 * len)] = 0;
if (strncmp(ses->serverNOS,
"NT LAN Manager 4", 16) == 0) {
cFYI(1, ("NT4 server"));
@@ -2707,22 +2697,19 @@ CIFSSessSetup(unsigned int xid, struct cifsSesInfo *ses,
}
remaining_words -= len + 1;
if (remaining_words > 0) {
- len = UniStrnlen((wchar_t *) bcc_ptr, remaining_words);
- /* last string is not always null terminated
- (for e.g. for Windows XP & 2000) */
- if (ses->serverDomain)
- kfree(ses->serverDomain);
- ses->serverDomain =
- kzalloc(2*(len+1),
- GFP_KERNEL);
- if (ses->serverDomain == NULL)
+ /* Win2K and Windows XP seem to
+ * have a major bug in not null
+ * terminating last Unicode
+ * string in response */
+ kfree(ses->serverDomain);
+ rc = cifs_ucs_to_nls(
+ &(ses->serverDomain),
+ bcc_ptr,
+ remaining_words, &len,
+ nls_codepage);
+ if (rc)
goto sesssetup_nomem;
- cifs_strfromUCS_le(ses->serverDomain,
- (__le16 *)bcc_ptr,
- len, nls_codepage);
bcc_ptr += 2 * (len + 1);
- ses->serverDomain[2*len] = 0;
- ses->serverDomain[1+(2*len)] = 0;
} else { /* else no more room so create
dummy domain string */
if (ses->serverDomain)
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 5c68b42..1c50063 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -301,33 +301,32 @@ static int decode_unicode_ssetup(char **pbcc_area, int bleft,
words_left = bleft / 2;
/* save off server operating system */
- len = UniStrnlen((wchar_t *) data, words_left);
-/* We look for obvious messed up bcc or strings in response so we do not go off
- the end since (at least) WIN2K and Windows XP have a major bug in not null
- terminating last Unicode string in response */
+ /* Win2K and Windows XP seem to have a major bug in not null terminating
+ * last unicode string in response */
+ kfree(ses->serverOS);
+ rc = cifs_ucs_to_nls(&(ses->serverOS), data, words_left, &len, nls_cp);
+ if (rc)
+ return rc;
+
if (len >= words_left)
return rc;
- kfree(ses->serverOS);
- /* UTF-8 string will not grow more than four times as big as UCS-16 */
- ses->serverOS = kzalloc((4 * len) + 2 /* trailing null */, GFP_KERNEL);
- if (ses->serverOS != NULL)
- cifs_strfromUCS_le(ses->serverOS, (__le16 *)data, len, nls_cp);
data += 2 * (len + 1);
words_left -= len + 1;
/* save off server network operating system */
- len = UniStrnlen((wchar_t *) data, words_left);
- if (len >= words_left)
+ /* Win2K and Windows XP seem to have a major bug in not null terminating
+ * last unicode string in response */
+ kfree(ses->serverNOS);
+ rc = cifs_ucs_to_nls(&(ses->serverNOS), data, words_left, &len, nls_cp);
+ if (rc)
return rc;
- kfree(ses->serverNOS);
- ses->serverNOS = kzalloc((4 * len) + 2 /* trailing null */, GFP_KERNEL);
+ if (len >= words_left)
+ return rc;
if (ses->serverNOS != NULL) {
- cifs_strfromUCS_le(ses->serverNOS, (__le16 *)data, len,
- nls_cp);
if (strncmp(ses->serverNOS, "NT LAN Manager 4", 16) == 0) {
cFYI(1, ("NT4 server"));
ses->flags |= CIFS_SES_NT4;
@@ -337,19 +336,18 @@ static int decode_unicode_ssetup(char **pbcc_area, int bleft,
words_left -= len + 1;
/* save off server domain */
- len = UniStrnlen((wchar_t *) data, words_left);
+
+ /* Win2K and Windows XP seem to have a major bug in not null terminating
+ * last unicode string in response */
+ kfree(ses->serverDomain);
+ rc = cifs_ucs_to_nls(&(ses->serverDomain), data, words_left, &len,
+ nls_cp);
+ if (rc)
+ return rc;
if (len > words_left)
return rc;
- kfree(ses->serverDomain);
- ses->serverDomain = kzalloc(2 * (len + 1), GFP_KERNEL); /* BB FIXME wrong length */
- if (ses->serverDomain != NULL) {
- cifs_strfromUCS_le(ses->serverDomain, (__le16 *)data, len,
- nls_cp);
- ses->serverDomain[2*len] = 0;
- ses->serverDomain[(2*len) + 1] = 0;
- }
data += 2 * (len + 1);
words_left -= len + 1;
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