The classic implementation of ramfs and many other user fileservers based on it have a serious bug regarding the 9p protocol :
If you open a file for which you have Read/Execute Permission you are free to write to that file by sending Twrite requests. * * *rwrite doesn't check if the file was opened for read, write or execute. * A possible solution for this problem is enhancing the meaning of Fid.open from an indicator for open files to an indicator for open files and the mode they were opened : 0x80 ... file is open 0x40 ... opened for reading 0x20 ... opened for writing 0x10 ... opened for execution While ramfs is regared as a toy program with minimal permission checking many user file servers around are based on this example like all the tools in tapefs. ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/T08f89c41317a2e69-M990b45a03a13257b66e4e8bc Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
