From 98de59bfe4b2ff6344d9ad8e5296f80de5dcc5b6 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 30 May 2012 19:58:30 -0400 Subject: take calculation of final prot in security_mmap_file() into a helper Signed-off-by: Al Viro --- security/security.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-) (limited to 'security/security.c') diff --git a/security/security.c b/security/security.c index 3b11b3b72fe2..3efc9b12aef4 100644 --- a/security/security.c +++ b/security/security.c @@ -660,36 +660,46 @@ int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg) return security_ops->file_ioctl(file, cmd, arg); } -int security_mmap_file(struct file *file, unsigned long prot, - unsigned long flags) +static inline unsigned long mmap_prot(struct file *file, unsigned long prot) { - unsigned long reqprot = prot; - int ret; /* - * Does the application expect PROT_READ to imply PROT_EXEC? - * - * (the exception is when the underlying filesystem is noexec - * mounted, in which case we dont add PROT_EXEC.) + * Does we have PROT_READ and does the application expect + * it to imply PROT_EXEC? If not, nothing to talk about... */ - if (!(reqprot & PROT_READ)) - goto out; + if ((prot & (PROT_READ | PROT_EXEC)) != PROT_READ) + return prot; if (!(current->personality & READ_IMPLIES_EXEC)) - goto out; - if (!file) { - prot |= PROT_EXEC; - } else if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) { + return prot; + /* + * if that's an anonymous mapping, let it. + */ + if (!file) + return prot | PROT_EXEC; + /* + * ditto if it's not on noexec mount, except that on !MMU we need + * BDI_CAP_EXEC_MMAP (== VM_MAYEXEC) in this case + */ + if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) { #ifndef CONFIG_MMU unsigned long caps = 0; struct address_space *mapping = file->f_mapping; if (mapping && mapping->backing_dev_info) caps = mapping->backing_dev_info->capabilities; if (!(caps & BDI_CAP_EXEC_MAP)) - goto out; + return prot; #endif - prot |= PROT_EXEC; + return prot | PROT_EXEC; } -out: - ret = security_ops->mmap_file(file, reqprot, prot, flags); + /* anything on noexec mount won't get PROT_EXEC */ + return prot; +} + +int security_mmap_file(struct file *file, unsigned long prot, + unsigned long flags) +{ + int ret; + ret = security_ops->mmap_file(file, prot, + mmap_prot(file, prot), flags); if (ret) return ret; return ima_file_mmap(file, prot); -- cgit v1.2.3-58-ga151