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apparmor: Move path lookup to using preallocated buffers

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Dynamically allocating buffers is problematic and is an extra layer
that is a potntial point of failure and can slow down mediation.
Change path lookup to use the preallocated per cpu buffers.

Signed-off-by: John Johansen <john.johansen@canonical.com>
This commit is contained in:
John Johansen
2017-05-23 03:25:14 -07:00
parent 72c8a76864
commit 4227c333f6
4 changed files with 53 additions and 86 deletions
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13
security/apparmor/file.c
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@@ -285,7 +285,8 @@ int aa_path_perm(const char *op, struct aa_profile *profile,
int error;
flags |= profile->path_flags | (S_ISDIR(cond->mode) ? PATH_IS_DIR : 0);
error = aa_path_name(path, flags, &buffer, &name, &info,
get_buffers(buffer);
error = aa_path_name(path, flags, buffer, &name, &info,
profile->disconnected);
if (error) {
if (error == -ENOENT && is_deleted(path->dentry)) {
@@ -304,7 +305,7 @@ int aa_path_perm(const char *op, struct aa_profile *profile,
}
error = aa_audit_file(profile, &perms, op, request, name, NULL,
cond->uid, info, error);
kfree(buffer);
put_buffers(buffer);
return error;
}
@@ -363,16 +364,17 @@ int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
unsigned int state;
int error;
get_buffers(buffer, buffer2);
lperms = nullperms;
/* buffer freed below, lname is pointer in buffer */
error = aa_path_name(&link, profile->path_flags, &buffer, &lname,
error = aa_path_name(&link, profile->path_flags, buffer, &lname,
&info, profile->disconnected);
if (error)
goto audit;
/* buffer2 freed below, tname is pointer in buffer2 */
error = aa_path_name(&target, profile->path_flags, &buffer2, &tname,
error = aa_path_name(&target, profile->path_flags, buffer2, &tname,
&info, profile->disconnected);
if (error)
goto audit;
@@ -432,8 +434,7 @@ done_tests:
audit:
error = aa_audit_file(profile, &lperms, OP_LINK, request,
lname, tname, cond.uid, info, error);
kfree(buffer);
kfree(buffer2);
put_buffers(buffer, buffer2);
return error;
}