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SubjectRe: [PATCH -v3 1/3] Capabilities: move cap_file_mmap to commoncap.c
Quoting Eric Paris (eparis@redhat.com):
> Currently we duplicate the mmap_min_addr test in cap_file_mmap and in
> security_file_mmap if !CONFIG_SECURITY. This patch moves cap_file_mmap
> into commoncap.c and then calls that function directly from
> security_file_mmap ifndef CONFIG_SECURITY like all of the other capability
> checks are done.

It also

1. changes the return value in error case from -EACCES to
-EPERM
2. no onger sets PF_SUPERPRIV in t->flags if the capability
is used.

Do we care about these?

-serge

> Signed-off-by: Eric Paris <eparis@redhat.com>
> ---
>
> include/linux/security.h | 7 ++++---
> security/capability.c | 9 ---------
> security/commoncap.c | 24 ++++++++++++++++++++++++
> 3 files changed, 28 insertions(+), 12 deletions(-)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 1459091..963a48f 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -66,6 +66,9 @@ extern int cap_inode_setxattr(struct dentry *dentry, const char *name,
> extern int cap_inode_removexattr(struct dentry *dentry, const char *name);
> extern int cap_inode_need_killpriv(struct dentry *dentry);
> extern int cap_inode_killpriv(struct dentry *dentry);
> +extern int cap_file_mmap(struct file *file, unsigned long reqprot,
> + unsigned long prot, unsigned long flags,
> + unsigned long addr, unsigned long addr_only);
> extern int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags);
> extern int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> unsigned long arg4, unsigned long arg5);
> @@ -2197,9 +2200,7 @@ static inline int security_file_mmap(struct file *file, unsigned long reqprot,
> unsigned long addr,
> unsigned long addr_only)
> {
> - if ((addr < mmap_min_addr) && !capable(CAP_SYS_RAWIO))
> - return -EACCES;
> - return 0;
> + return cap_file_mmap(file, reqprot, prot, flags, addr, addr_only);
> }
>
> static inline int security_file_mprotect(struct vm_area_struct *vma,
> diff --git a/security/capability.c b/security/capability.c
> index f218dd3..ec05730 100644
> --- a/security/capability.c
> +++ b/security/capability.c
> @@ -330,15 +330,6 @@ static int cap_file_ioctl(struct file *file, unsigned int command,
> return 0;
> }
>
> -static int cap_file_mmap(struct file *file, unsigned long reqprot,
> - unsigned long prot, unsigned long flags,
> - unsigned long addr, unsigned long addr_only)
> -{
> - if ((addr < mmap_min_addr) && !capable(CAP_SYS_RAWIO))
> - return -EACCES;
> - return 0;
> -}
> -
> static int cap_file_mprotect(struct vm_area_struct *vma, unsigned long reqprot,
> unsigned long prot)
> {
> diff --git a/security/commoncap.c b/security/commoncap.c
> index aa97704..9a731d7 100644
> --- a/security/commoncap.c
> +++ b/security/commoncap.c
> @@ -984,3 +984,27 @@ int cap_vm_enough_memory(struct mm_struct *mm, long pages)
> cap_sys_admin = 1;
> return __vm_enough_memory(mm, pages, cap_sys_admin);
> }
> +
> +/*
> + * cap_file_mmap - check if able to map given addr
> + * @file: unused
> + * @reqprot: unused
> + * @prot: unused
> + * @flags: unused
> + * @addr: address attempting to be mapped
> + * @addr_only: unused
> + *
> + * If the process is attempting to map memory below mmap_min_addr they need
> + * CAP_SYS_RAWIO. The other parameters to this function are unused by the
> + * capability security module. Returns 0 if this mapping should be allowed
> + * -EPERM if not.
> + */
> +int cap_file_mmap(struct file *file, unsigned long reqprot,
> + unsigned long prot, unsigned long flags,
> + unsigned long addr, unsigned long addr_only)
> +{
> + if (addr < mmap_min_addr)
> + return cap_capable(current, current_cred(), CAP_SYS_RAWIO,
> + SECURITY_CAP_AUDIT);
> + return 0;
> +}
>
> --
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