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author | Miklos Szeredi <mszeredi@suse.cz> | 2007-10-16 23:27:08 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-17 08:42:52 -0700 |
commit | 22590e41cb569add194829c08dc0ceea74b38a65 (patch) | |
tree | 0db73fe0e78bcde816dcf289e0aa5323abf73833 /fs/namei.c | |
parent | 043f46f6151df2c518988b5e41376e42491257b5 (diff) | |
download | kernel_samsung_espresso10-22590e41cb569add194829c08dc0ceea74b38a65.zip kernel_samsung_espresso10-22590e41cb569add194829c08dc0ceea74b38a65.tar.gz kernel_samsung_espresso10-22590e41cb569add194829c08dc0ceea74b38a65.tar.bz2 |
fix execute checking in permission()
permission() checks that MAY_EXEC is only allowed on regular files if at least
one execute bit is set in the file mode.
generic_permission() already ensures this, so the extra check in permission()
is superfluous.
If the filesystem defines it's own ->permission() the check may still be
needed. In this case move it after ->permission(). This is needed because
filesystems such as FUSE may need to refresh the inode attributes before
checking permissions.
This check should be moved inside ->permission(), but that's another story.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/namei.c')
-rw-r--r-- | fs/namei.c | 36 |
1 files changed, 24 insertions, 12 deletions
@@ -227,10 +227,10 @@ int generic_permission(struct inode *inode, int mask, int permission(struct inode *inode, int mask, struct nameidata *nd) { - umode_t mode = inode->i_mode; int retval, submask; if (mask & MAY_WRITE) { + umode_t mode = inode->i_mode; /* * Nobody gets write access to a read-only fs. @@ -246,22 +246,34 @@ int permission(struct inode *inode, int mask, struct nameidata *nd) return -EACCES; } - - /* - * MAY_EXEC on regular files requires special handling: We override - * filesystem execute permissions if the mode bits aren't set or - * the fs is mounted with the "noexec" flag. - */ - if ((mask & MAY_EXEC) && S_ISREG(mode) && (!(mode & S_IXUGO) || - (nd && nd->mnt && (nd->mnt->mnt_flags & MNT_NOEXEC)))) - return -EACCES; + if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) { + /* + * MAY_EXEC on regular files is denied if the fs is mounted + * with the "noexec" flag. + */ + if (nd && nd->mnt && (nd->mnt->mnt_flags & MNT_NOEXEC)) + return -EACCES; + } /* Ordinary permission routines do not understand MAY_APPEND. */ submask = mask & ~MAY_APPEND; - if (inode->i_op && inode->i_op->permission) + if (inode->i_op && inode->i_op->permission) { retval = inode->i_op->permission(inode, submask, nd); - else + if (!retval) { + /* + * Exec permission on a regular file is denied if none + * of the execute bits are set. + * + * This check should be done by the ->permission() + * method. + */ + if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) && + !(inode->i_mode & S_IXUGO)) + return -EACCES; + } + } else { retval = generic_permission(inode, submask, NULL); + } if (retval) return retval; |