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Commit 7ac86265 authored by Jeff Layton's avatar Jeff Layton Committed by Al Viro
Browse files

audit: allow audit code to satisfy getname requests from its names_list 



Currently, if we call getname() on a userland string more than once,
we'll get multiple copies of the string and multiple audit_names
records.

Add a function that will allow the audit_names code to satisfy getname
requests using info from the audit_names list, avoiding a new allocation
and audit_names records.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 91a27b2a

fs/namei.c

+4 −0
Original line number Diff line number Diff line
@@ -130,6 +130,10 @@ getname_flags(const char __user *filename, int flags, int *empty) 
	char *kname;

	int len;



	result = audit_reusename(filename);

	if (result)

		return result;



	/* FIXME: create dedicated slabcache? */

	result = kzalloc(sizeof(*result), GFP_KERNEL);

	if (unlikely(!result))

include/linux/audit.h

+11 −0
Original line number Diff line number Diff line
@@ -471,6 +471,7 @@ extern void __audit_syscall_entry(int arch, 
				  int major, unsigned long a0, unsigned long a1,

				  unsigned long a2, unsigned long a3);

extern void __audit_syscall_exit(int ret_success, long ret_value);

extern struct filename *__audit_reusename(const __user char *uptr);

extern void __audit_getname(struct filename *name);

extern void audit_putname(struct filename *name);

extern void __audit_inode(const char *name, const struct dentry *dentry,
@@ -507,6 +508,12 @@ static inline void audit_syscall_exit(void *pt_regs) 
		__audit_syscall_exit(success, return_code);

	}

}

static inline struct filename *audit_reusename(const __user char *name)

{

	if (unlikely(!audit_dummy_context()))

		return __audit_reusename(name);

	return NULL;

}

static inline void audit_getname(struct filename *name)

{

	if (unlikely(!audit_dummy_context()))
@@ -665,6 +672,10 @@ static inline int audit_dummy_context(void) 
{

	return 1;

}

static inline struct filename *audit_reusename(const __user char *name)

{

	return NULL;

}

static inline void audit_getname(struct filename *name)

{ }

static inline void audit_putname(struct filename *name)

kernel/auditsc.c

+23 −0
Original line number Diff line number Diff line
@@ -2020,6 +2020,29 @@ static struct audit_names *audit_alloc_name(struct audit_context *context, 
	return aname;

}



/**

 * audit_reusename - fill out filename with info from existing entry

 * @uptr: userland ptr to pathname

 *

 * Search the audit_names list for the current audit context. If there is an

 * existing entry with a matching "uptr" then return the filename

 * associated with that audit_name. If not, return NULL.

 */

struct filename *

__audit_reusename(const __user char *uptr)

{

	struct audit_context *context = current->audit_context;

	struct audit_names *n;



	list_for_each_entry(n, &context->names_list, list) {

		if (!n->name)

			continue;

		if (n->name->uptr == uptr)

			return n->name;

	}

	return NULL;

}



/**

 * audit_getname - add a name to the list

 * @name: name to add