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-rw-r--r--fs/cifs/link.c372
1 files changed, 348 insertions, 24 deletions
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 473ca803365..85cdbf831e7 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -28,6 +28,296 @@
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"
+#include "md5.h"
+
+#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
+#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
+#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
+#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
+#define CIFS_MF_SYMLINK_FILE_SIZE \
+ (CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
+
+#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
+#define CIFS_MF_SYMLINK_MD5_FORMAT \
+ "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x\n"
+#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) \
+ md5_hash[0], md5_hash[1], md5_hash[2], md5_hash[3], \
+ md5_hash[4], md5_hash[5], md5_hash[6], md5_hash[7], \
+ md5_hash[8], md5_hash[9], md5_hash[10], md5_hash[11],\
+ md5_hash[12], md5_hash[13], md5_hash[14], md5_hash[15]
+
+static int
+CIFSParseMFSymlink(const u8 *buf,
+ unsigned int buf_len,
+ unsigned int *_link_len,
+ char **_link_str)
+{
+ int rc;
+ unsigned int link_len;
+ const char *md5_str1;
+ const char *link_str;
+ struct MD5Context md5_ctx;
+ u8 md5_hash[16];
+ char md5_str2[34];
+
+ if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+ return -EINVAL;
+
+ md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
+ link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
+
+ rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
+ if (rc != 1)
+ return -EINVAL;
+
+ cifs_MD5_init(&md5_ctx);
+ cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
+ cifs_MD5_final(md5_hash, &md5_ctx);
+
+ snprintf(md5_str2, sizeof(md5_str2),
+ CIFS_MF_SYMLINK_MD5_FORMAT,
+ CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+ if (strncmp(md5_str1, md5_str2, 17) != 0)
+ return -EINVAL;
+
+ if (_link_str) {
+ *_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
+ if (!*_link_str)
+ return -ENOMEM;
+ }
+
+ *_link_len = link_len;
+ return 0;
+}
+
+static int
+CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
+{
+ unsigned int link_len;
+ unsigned int ofs;
+ struct MD5Context md5_ctx;
+ u8 md5_hash[16];
+
+ if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+ return -EINVAL;
+
+ link_len = strlen(link_str);
+
+ if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
+ return -ENAMETOOLONG;
+
+ cifs_MD5_init(&md5_ctx);
+ cifs_MD5_update(&md5_ctx, (const u8 *)link_str, link_len);
+ cifs_MD5_final(md5_hash, &md5_ctx);
+
+ snprintf(buf, buf_len,
+ CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
+ link_len,
+ CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+ ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
+ memcpy(buf + ofs, link_str, link_len);
+
+ ofs += link_len;
+ if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+ buf[ofs] = '\n';
+ ofs++;
+ }
+
+ while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+ buf[ofs] = ' ';
+ ofs++;
+ }
+
+ return 0;
+}
+
+static int
+CIFSCreateMFSymLink(const int xid, struct cifsTconInfo *tcon,
+ const char *fromName, const char *toName,
+ const struct nls_table *nls_codepage, int remap)
+{
+ int rc;
+ int oplock = 0;
+ __u16 netfid = 0;
+ u8 *buf;
+ unsigned int bytes_written = 0;
+
+ buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ rc = CIFSFormatMFSymlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
+ if (rc != 0) {
+ kfree(buf);
+ return rc;
+ }
+
+ rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
+ CREATE_NOT_DIR, &netfid, &oplock, NULL,
+ nls_codepage, remap);
+ if (rc != 0) {
+ kfree(buf);
+ return rc;
+ }
+
+ rc = CIFSSMBWrite(xid, tcon, netfid,
+ CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+ 0 /* offset */,
+ &bytes_written, buf, NULL, 0);
+ CIFSSMBClose(xid, tcon, netfid);
+ kfree(buf);
+ if (rc != 0)
+ return rc;
+
+ if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
+ return -EIO;
+
+ return 0;
+}
+
+static int
+CIFSQueryMFSymLink(const int xid, struct cifsTconInfo *tcon,
+ const unsigned char *searchName, char **symlinkinfo,
+ const struct nls_table *nls_codepage, int remap)
+{
+ int rc;
+ int oplock = 0;
+ __u16 netfid = 0;
+ u8 *buf;
+ char *pbuf;
+ unsigned int bytes_read = 0;
+ int buf_type = CIFS_NO_BUFFER;
+ unsigned int link_len = 0;
+ FILE_ALL_INFO file_info;
+
+ rc = CIFSSMBOpen(xid, tcon, searchName, FILE_OPEN, GENERIC_READ,
+ CREATE_NOT_DIR, &netfid, &oplock, &file_info,
+ nls_codepage, remap);
+ if (rc != 0)
+ return rc;
+
+ if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
+ CIFSSMBClose(xid, tcon, netfid);
+ /* it's not a symlink */
+ return -EINVAL;
+ }
+
+ buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+ pbuf = buf;
+
+ rc = CIFSSMBRead(xid, tcon, netfid,
+ CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+ 0 /* offset */,
+ &bytes_read, &pbuf, &buf_type);
+ CIFSSMBClose(xid, tcon, netfid);
+ if (rc != 0) {
+ kfree(buf);
+ return rc;
+ }
+
+ rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, symlinkinfo);
+ kfree(buf);
+ if (rc != 0)
+ return rc;
+
+ return 0;
+}
+
+bool
+CIFSCouldBeMFSymlink(const struct cifs_fattr *fattr)
+{
+ if (!(fattr->cf_mode & S_IFREG))
+ /* it's not a symlink */
+ return false;
+
+ if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
+ /* it's not a symlink */
+ return false;
+
+ return true;
+}
+
+int
+CIFSCheckMFSymlink(struct cifs_fattr *fattr,
+ const unsigned char *path,
+ struct cifs_sb_info *cifs_sb, int xid)
+{
+ int rc;
+ int oplock = 0;
+ __u16 netfid = 0;
+ struct tcon_link *tlink;
+ struct cifsTconInfo *pTcon;
+ u8 *buf;
+ char *pbuf;
+ unsigned int bytes_read = 0;
+ int buf_type = CIFS_NO_BUFFER;
+ unsigned int link_len = 0;
+ FILE_ALL_INFO file_info;
+
+ if (!CIFSCouldBeMFSymlink(fattr))
+ /* it's not a symlink */
+ return 0;
+
+ tlink = cifs_sb_tlink(cifs_sb);
+ if (IS_ERR(tlink))
+ return PTR_ERR(tlink);
+ pTcon = tlink_tcon(tlink);
+
+ rc = CIFSSMBOpen(xid, pTcon, path, FILE_OPEN, GENERIC_READ,
+ CREATE_NOT_DIR, &netfid, &oplock, &file_info,
+ cifs_sb->local_nls,
+ cifs_sb->mnt_cifs_flags &
+ CIFS_MOUNT_MAP_SPECIAL_CHR);
+ if (rc != 0)
+ goto out;
+
+ if (file_info.EndOfFile != CIFS_MF_SYMLINK_FILE_SIZE) {
+ CIFSSMBClose(xid, pTcon, netfid);
+ /* it's not a symlink */
+ goto out;
+ }
+
+ buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+ if (!buf) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ pbuf = buf;
+
+ rc = CIFSSMBRead(xid, pTcon, netfid,
+ CIFS_MF_SYMLINK_FILE_SIZE /* length */,
+ 0 /* offset */,
+ &bytes_read, &pbuf, &buf_type);
+ CIFSSMBClose(xid, pTcon, netfid);
+ if (rc != 0) {
+ kfree(buf);
+ goto out;
+ }
+
+ rc = CIFSParseMFSymlink(buf, bytes_read, &link_len, NULL);
+ kfree(buf);
+ if (rc == -EINVAL) {
+ /* it's not a symlink */
+ rc = 0;
+ goto out;
+ }
+
+ if (rc != 0)
+ goto out;
+
+ /* it is a symlink */
+ fattr->cf_eof = link_len;
+ fattr->cf_mode &= ~S_IFMT;
+ fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
+ fattr->cf_dtype = DT_LNK;
+out:
+ cifs_put_tlink(tlink);
+ return rc;
+}
int
cifs_hardlink(struct dentry *old_file, struct inode *inode,
@@ -37,17 +327,17 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
int xid;
char *fromName = NULL;
char *toName = NULL;
- struct cifs_sb_info *cifs_sb_target;
+ struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+ struct tcon_link *tlink;
struct cifsTconInfo *pTcon;
struct cifsInodeInfo *cifsInode;
- xid = GetXid();
-
- cifs_sb_target = CIFS_SB(inode->i_sb);
- pTcon = cifs_sb_target->tcon;
+ tlink = cifs_sb_tlink(cifs_sb);
+ if (IS_ERR(tlink))
+ return PTR_ERR(tlink);
+ pTcon = tlink_tcon(tlink);
-/* No need to check for cross device links since server will do that
- BB note DFS case in future though (when we may have to check) */
+ xid = GetXid();
fromName = build_path_from_dentry(old_file);
toName = build_path_from_dentry(direntry);
@@ -56,16 +346,15 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
goto cifs_hl_exit;
}
-/* if (cifs_sb_target->tcon->ses->capabilities & CAP_UNIX)*/
if (pTcon->unix_ext)
rc = CIFSUnixCreateHardLink(xid, pTcon, fromName, toName,
- cifs_sb_target->local_nls,
- cifs_sb_target->mnt_cifs_flags &
+ cifs_sb->local_nls,
+ cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
else {
rc = CIFSCreateHardLink(xid, pTcon, fromName, toName,
- cifs_sb_target->local_nls,
- cifs_sb_target->mnt_cifs_flags &
+ cifs_sb->local_nls,
+ cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
if ((rc == -EIO) || (rc == -EINVAL))
rc = -EOPNOTSUPP;
@@ -101,6 +390,7 @@ cifs_hl_exit:
kfree(fromName);
kfree(toName);
FreeXid(xid);
+ cifs_put_tlink(tlink);
return rc;
}
@@ -113,10 +403,19 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
char *full_path = NULL;
char *target_path = NULL;
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
- struct cifsTconInfo *tcon = cifs_sb->tcon;
+ struct tcon_link *tlink = NULL;
+ struct cifsTconInfo *tcon;
xid = GetXid();
+ tlink = cifs_sb_tlink(cifs_sb);
+ if (IS_ERR(tlink)) {
+ rc = PTR_ERR(tlink);
+ tlink = NULL;
+ goto out;
+ }
+ tcon = tlink_tcon(tlink);
+
/*
* For now, we just handle symlinks with unix extensions enabled.
* Eventually we should handle NTFS reparse points, and MacOS
@@ -130,7 +429,8 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
* but there doesn't seem to be any harm in allowing the client to
* read them.
*/
- if (!(tcon->ses->capabilities & CAP_UNIX)) {
+ if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+ && !(tcon->ses->capabilities & CAP_UNIX)) {
rc = -EACCES;
goto out;
}
@@ -141,8 +441,21 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
cFYI(1, "Full path: %s inode = 0x%p", full_path, inode);
- rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
- cifs_sb->local_nls);
+ rc = -EACCES;
+ /*
+ * First try Minshall+French Symlinks, if configured
+ * and fallback to UNIX Extensions Symlinks.
+ */
+ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+ rc = CIFSQueryMFSymLink(xid, tcon, full_path, &target_path,
+ cifs_sb->local_nls,
+ cifs_sb->mnt_cifs_flags &
+ CIFS_MOUNT_MAP_SPECIAL_CHR);
+
+ if ((rc != 0) && (tcon->ses->capabilities & CAP_UNIX))
+ rc = CIFSSMBUnixQuerySymLink(xid, tcon, full_path, &target_path,
+ cifs_sb->local_nls);
+
kfree(full_path);
out:
if (rc != 0) {
@@ -151,6 +464,8 @@ out:
}
FreeXid(xid);
+ if (tlink)
+ cifs_put_tlink(tlink);
nd_set_link(nd, target_path);
return NULL;
}
@@ -160,29 +475,37 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
{
int rc = -EOPNOTSUPP;
int xid;
- struct cifs_sb_info *cifs_sb;
+ struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+ struct tcon_link *tlink;
struct cifsTconInfo *pTcon;
char *full_path = NULL;
struct inode *newinode = NULL;
xid = GetXid();
- cifs_sb = CIFS_SB(inode->i_sb);
- pTcon = cifs_sb->tcon;
+ tlink = cifs_sb_tlink(cifs_sb);
+ if (IS_ERR(tlink)) {
+ rc = PTR_ERR(tlink);
+ goto symlink_exit;
+ }
+ pTcon = tlink_tcon(tlink);
full_path = build_path_from_dentry(direntry);
-
if (full_path == NULL) {
rc = -ENOMEM;
- FreeXid(xid);
- return rc;
+ goto symlink_exit;
}
cFYI(1, "Full path: %s", full_path);
cFYI(1, "symname is %s", symname);
/* BB what if DFS and this volume is on different share? BB */
- if (pTcon->unix_ext)
+ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
+ rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
+ cifs_sb->local_nls,
+ cifs_sb->mnt_cifs_flags &
+ CIFS_MOUNT_MAP_SPECIAL_CHR);
+ else if (pTcon->unix_ext)
rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
cifs_sb->local_nls);
/* else
@@ -208,8 +531,9 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
d_instantiate(direntry, newinode);
}
}
-
+symlink_exit:
kfree(full_path);
+ cifs_put_tlink(tlink);
FreeXid(xid);
return rc;
}