cifs: fix dentry refcount leak when opening a FIFO on lookup
The cifs code will attempt to open files on lookup under certain circumstances. What happens though if we find that the file we opened was actually a FIFO or other special file? Currently, the open filehandle just ends up being leaked leading to a dentry refcount mismatch and oops on umount. Fix this by having the code close the filehandle on the server if it turns out not to be a regular file. While we're at it, change this spaghetti if statement into a switch too. Cc: stable@vger.kernel.org Reported-by: CAI Qian <caiqian@redhat.com> Tested-by: CAI Qian <caiqian@redhat.com> Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
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@ -584,10 +584,26 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
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* If either that or op not supported returned, follow
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* If either that or op not supported returned, follow
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* the normal lookup.
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* the normal lookup.
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*/
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*/
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if ((rc == 0) || (rc == -ENOENT))
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switch (rc) {
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case 0:
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/*
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* The server may allow us to open things like
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* FIFOs, but the client isn't set up to deal
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* with that. If it's not a regular file, just
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* close it and proceed as if it were a normal
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* lookup.
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*/
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if (newInode && !S_ISREG(newInode->i_mode)) {
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CIFSSMBClose(xid, pTcon, fileHandle);
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break;
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}
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case -ENOENT:
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posix_open = true;
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posix_open = true;
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else if ((rc == -EINVAL) || (rc != -EOPNOTSUPP))
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case -EOPNOTSUPP:
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break;
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default:
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pTcon->broken_posix_open = true;
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pTcon->broken_posix_open = true;
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}
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}
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}
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if (!posix_open)
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if (!posix_open)
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rc = cifs_get_inode_info_unix(&newInode, full_path,
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rc = cifs_get_inode_info_unix(&newInode, full_path,
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