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resolved conflicts for merge of 2baeb89 to honeycomb-plus-aosp
Change-Id: Ib3169b3a36aa13ef413da624355b1737e9b76fd9
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/* | ||
* Copyright (C) 2011 The Android Open Source Project | ||
* | ||
* Licensed under the Apache License, Version 2.0 (the "License"); | ||
* you may not use this file except in compliance with the License. | ||
* You may obtain a copy of the License at | ||
* | ||
* http://www.apache.org/licenses/LICENSE-2.0 | ||
* | ||
* Unless required by applicable law or agreed to in writing, software | ||
* distributed under the License is distributed on an "AS IS" BASIS, | ||
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
* See the License for the specific language governing permissions and | ||
* limitations under the License. | ||
*/ | ||
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#ifndef __CUTILS_UEVENT_H | ||
#define __CUTILS_UEVENT_H | ||
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#include <sys/socket.h> | ||
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#ifdef __cplusplus | ||
extern "C" { | ||
#endif | ||
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ssize_t uevent_checked_recv(int socket, void *buffer, size_t length); | ||
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#ifdef __cplusplus | ||
} | ||
#endif | ||
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#endif /* __CUTILS_UEVENT_H */ |
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,70 @@ | ||
/* | ||
* Copyright (C) 2011 The Android Open Source Project | ||
* | ||
* Licensed under the Apache License, Version 2.0 (the "License"); | ||
* you may not use this file except in compliance with the License. | ||
* You may obtain a copy of the License at | ||
* | ||
* http://www.apache.org/licenses/LICENSE-2.0 | ||
* | ||
* Unless required by applicable law or agreed to in writing, software | ||
* distributed under the License is distributed on an "AS IS" BASIS, | ||
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
* See the License for the specific language governing permissions and | ||
* limitations under the License. | ||
*/ | ||
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#include <cutils/uevent.h> | ||
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#include <errno.h> | ||
#include <strings.h> | ||
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#include <linux/netlink.h> | ||
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/** | ||
* Like recv(), but checks that messages actually originate from the kernel. | ||
*/ | ||
ssize_t uevent_checked_recv(int socket, void *buffer, size_t length) { | ||
struct iovec iov = { buffer, length }; | ||
struct sockaddr_nl addr; | ||
char control[CMSG_SPACE(sizeof(struct ucred))]; | ||
struct msghdr hdr = { | ||
&addr, | ||
sizeof(addr), | ||
&iov, | ||
1, | ||
control, | ||
sizeof(control), | ||
0, | ||
}; | ||
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ssize_t n = recvmsg(socket, &hdr, 0); | ||
if (n <= 0) { | ||
return n; | ||
} | ||
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if (addr.nl_groups == 0 || addr.nl_pid != 0) { | ||
/* ignoring non-kernel or unicast netlink message */ | ||
goto out; | ||
} | ||
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struct cmsghdr *cmsg = CMSG_FIRSTHDR(&hdr); | ||
if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { | ||
/* ignoring netlink message with no sender credentials */ | ||
goto out; | ||
} | ||
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struct ucred *cred = (struct ucred *)CMSG_DATA(cmsg); | ||
if (cred->uid != 0) { | ||
/* ignoring netlink message from non-root user */ | ||
goto out; | ||
} | ||
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return n; | ||
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out: | ||
/* clear residual potentially malicious data */ | ||
bzero(buffer, length); | ||
errno = EIO; | ||
return -1; | ||
} |