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MFp4 @229482:

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- Limit bpf descriptor in unprivileged process to CAP_POLL_EVENT, CAP_READ and
  allow for SIOCGIFFLAGS, SIOCGIFMEDIA ioctls.
- While here limit bpf descriptor in privileged process to only CAP_WRITE.

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Pawel Jakub Dawidek 2013-07-03 22:16:02 +00:00
parent 235eb53002
commit 3b2ed0659c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=252628
1 changed files with 12 additions and 0 deletions
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12
sbin/dhclient/bpf.c
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@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
#include "dhcpd.h"
#include "privsep.h"
#include <sys/capability.h>
#include <sys/ioctl.h>
#include <sys/uio.h>
@ -159,6 +160,9 @@ if_register_send(struct interface_info *info)
if (ioctl(info->wfdesc, BIOCLOCK, NULL) < 0)
error("Cannot lock bpf");
if (cap_rights_limit(info->wfdesc, CAP_WRITE) < 0 && errno != ENOSYS)
error("Can't limit bpf descriptor: %m");
/*
* Use raw socket for unicast send.
*/
@ -208,6 +212,7 @@ int dhcp_bpf_filter_len = sizeof(dhcp_bpf_filter) / sizeof(struct bpf_insn);
void
if_register_receive(struct interface_info *info)
{
static const unsigned long cmds[2] = { SIOCGIFFLAGS, SIOCGIFMEDIA };
struct bpf_version v;
struct bpf_program p;
int flag = 1, sz;
@ -258,6 +263,13 @@ if_register_receive(struct interface_info *info)
if (ioctl(info->rfdesc, BIOCLOCK, NULL) < 0)
error("Cannot lock bpf");
if (cap_rights_limit(info->rfdesc,
CAP_IOCTL | CAP_POLL_EVENT | CAP_READ) < 0 && errno != ENOSYS) {
error("Can't limit bpf descriptor: %m");
}
if (cap_ioctls_limit(info->rfdesc, cmds, 2) < 0 && errno != ENOSYS)
error("Can't limit ioctls for bpf descriptor: %m");
}
void