Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Add file_ns_capable() helper function for open-time capability checking
Nothing is using it yet, but this will allow us to delay the open-time
checks to use time, without breaking the normal UNIX permission
semantics where permissions are determined by the opener (and the file
descriptor can then be passed to a different process, or the process can
drop capabilities).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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+2
include/linux/capability.h
+2
include/linux/capability.h
···
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#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t))
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struct file;
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struct inode;
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struct dentry;
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struct user_namespace;
···
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extern bool ns_capable(struct user_namespace *ns, int cap);
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extern bool nsown_capable(int cap);
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extern bool inode_capable(const struct inode *inode, int cap);
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extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
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/* audit system wants to get cap info from files as well */
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extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
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kernel/capability.c
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kernel/capability.c
···
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EXPORT_SYMBOL(ns_capable);
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/**
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* file_ns_capable - Determine if the file's opener had a capability in effect
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* @file: The file we want to check
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* @ns: The usernamespace we want the capability in
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* @cap: The capability to be tested for
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*
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* Return true if task that opened the file had a capability in effect
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* when the file was opened.
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*
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* This does not set PF_SUPERPRIV because the caller may not
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* actually be privileged.
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*/
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bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap)
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{
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if (WARN_ON_ONCE(!cap_valid(cap)))
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return false;
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if (security_capable(file->f_cred, ns, cap) == 0)
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return true;
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return false;
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}
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EXPORT_SYMBOL(file_ns_capable);
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/**
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* capable - Determine if the current task has a superior capability in effect
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* @cap: The capability to be tested for
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*