From 42492594043d621a7910ff5877c3eb9202870b45 Mon Sep 17 00:00:00 2001 From: "David P. Quigley" Date: Mon, 4 Feb 2008 22:29:39 -0800 Subject: VFS/Security: Rework inode_getsecurity and callers to return resulting buffer This patch modifies the interface to inode_getsecurity to have the function return a buffer containing the security blob and its length via parameters instead of relying on the calling function to give it an appropriately sized buffer. Security blobs obtained with this function should be freed using the release_secctx LSM hook. This alleviates the problem of the caller having to guess a length and preallocate a buffer for this function allowing it to be used elsewhere for Labeled NFS. The patch also removed the unused err parameter. The conversion is similar to the one performed by Al Viro for the security_getprocattr hook. Signed-off-by: David P. Quigley Cc: Stephen Smalley Cc: Chris Wright Acked-by: James Morris Acked-by: Serge Hallyn Cc: Casey Schaufler Cc: Al Viro Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- security/selinux/hooks.c | 43 +++++++++++++++---------------------------- 1 file changed, 15 insertions(+), 28 deletions(-) (limited to 'security/selinux') diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index be6de0b8734f..e5ed07510309 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -136,32 +136,6 @@ static DEFINE_SPINLOCK(sb_security_lock); static struct kmem_cache *sel_inode_cache; -/* Return security context for a given sid or just the context - length if the buffer is null or length is 0 */ -static int selinux_getsecurity(u32 sid, void *buffer, size_t size) -{ - char *context; - unsigned len; - int rc; - - rc = security_sid_to_context(sid, &context, &len); - if (rc) - return rc; - - if (!buffer || !size) - goto getsecurity_exit; - - if (size < len) { - len = -ERANGE; - goto getsecurity_exit; - } - memcpy(buffer, context, len); - -getsecurity_exit: - kfree(context); - return len; -} - /** * selinux_secmark_enabled - Check to see if SECMARK is currently enabled * @@ -2675,14 +2649,27 @@ static int selinux_inode_removexattr (struct dentry *dentry, char *name) * * Permission check is handled by selinux_inode_getxattr hook. */ -static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void *buffer, size_t size, int err) +static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc) { + u32 size; + int error; + char *context = NULL; struct inode_security_struct *isec = inode->i_security; if (strcmp(name, XATTR_SELINUX_SUFFIX)) return -EOPNOTSUPP; - return selinux_getsecurity(isec->sid, buffer, size); + error = security_sid_to_context(isec->sid, &context, &size); + if (error) + return error; + error = size; + if (alloc) { + *buffer = context; + goto out_nofree; + } + kfree(context); +out_nofree: + return error; } static int selinux_inode_setsecurity(struct inode *inode, const char *name, -- cgit v1.2.2