OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> writes: >>> > ATTR_FORCE is supposed to suppress permission checking altogether, and >>> > shouldn't be mixed with multiple attribute changes if some should be >>> > subject to permission checks while others should not. >>> >>> I disagree. In fact, ATTR_FORCE is just used for ATTR_KILL_S[UG]ID, and >>> notify_change() is disallowing the mixed ATTR_MODE and ATTR_KILL_*. I >>> think it should be enough. >> >> Ok, then we just need to adjust selinux_inode_setattr to understand that >> ATTR_FORCE only means to bypass checking on ATTR_MODE. > > Ok, sure. I'll try it. Could you review this? I've added ATTR_TIMES_SET to check explicit utimes(), and tried it with minimum change. [I'm not sure this handles notify_change() usage of nfsd (and perhaps other network fs too) correctly, and whether selinux may want to check it. I guess network fs _may_ try to change the multiple attributes at a time. Well, even if it's true, it would be another topic...] Thanks. -- OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> From: Amerigo Wang <amwang@xxxxxxxxxx> As suggested by OGAWA Hirofumi in thread: http://lkml.org/lkml/2009/8/7/132, we should let selinux_inode_setattr() to match our ATTR_* rules. ATTR_FORCE should not force things like ATTR_SIZE. Cc: Stephen Smalley <sds@xxxxxxxxxxxxx> Cc: Eric Paris <eparis@xxxxxxxxxx> Signed-off-by: WANG Cong <amwang@xxxxxxxxxx> [tweaks] Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> --- security/selinux/hooks.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff -puN security/selinux/hooks.c~selinux-truncate-fix security/selinux/hooks.c --- linux-2.6/security/selinux/hooks.c~selinux-truncate-fix 2009-08-18 03:50:09.000000000 +0900 +++ linux-2.6-hirofumi/security/selinux/hooks.c 2009-08-18 05:35:11.000000000 +0900 @@ -2711,12 +2711,17 @@ static int selinux_inode_permission(stru static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) { const struct cred *cred = current_cred(); + unsigned int ia_valid = iattr->ia_valid; - if (iattr->ia_valid & ATTR_FORCE) - return 0; + /* ATTR_FORCE is just used for ATTR_KILL_S[UG]ID. */ + if (ia_valid & ATTR_FORCE) { + ia_valid &= ~(ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_MODE); + if (!ia_valid) + return 0; + } - if (iattr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | - ATTR_ATIME_SET | ATTR_MTIME_SET)) + if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | + ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET)) return dentry_has_perm(cred, NULL, dentry, FILE__SETATTR); return dentry_has_perm(cred, NULL, dentry, FILE__WRITE); _ -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
