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| author | Jorge Lucangeli Obes <jorgelo@google.com> | 2015-09-30 18:08:47 -0700 |
|---|---|---|
| committer | Samuel Tan <samueltan@google.com> | 2015-10-01 09:52:53 -0700 |
| commit | e0b0b41fe04d8189ecea8045464b4870b7ce4e23 (patch) | |
| tree | ee36ee06307b58f4b0b510c29d6da5597403e887 | |
| parent | 14596ac959f09d8824dc2ee9a3b20ad7fe3de068 (diff) | |
| download | dhcpcd-6.8.2-e0b0b41fe04d8189ecea8045464b4870b7ce4e23.tar.gz | |
dhcpcd-6.8.2: switch user after starting dhcpcd-6.8.2
Have dhcpcd-6.8.2 switch itself to the dhcp uid and gid after
spawning. This assumes that dhcpcd-6.8.2 is started as root,
which is current the case when shill spawns it.
BUG: 24408645
TEST: dhcpcd-6.8.2 builds and is started successfully by shill.
Change-Id: Ia14c31ddd7ac06cc19f0541ae3c7bf0f019447ce
| -rw-r--r-- | dhcpcd.c | 40 |
1 files changed, 39 insertions, 1 deletions
@@ -49,6 +49,12 @@ const char dhcpcd_copyright[] = "Copyright (c) 2006-2015 Roy Marples"; #include <unistd.h> #include <time.h> +#if defined(__ANDROID__) +#include <sys/capability.h> +#include <sys/prctl.h> +#include <private/android_filesystem_config.h> +#endif /* __ANDROID__ */ + #include "config.h" #include "arp.h" #include "common.h" @@ -1398,6 +1404,30 @@ dhcpcd_handleargs(struct dhcpcd_ctx *ctx, struct fd_list *fd, return 0; } +#if defined(__ANDROID__) +static void +switch_user(void) +{ + gid_t groups[] = { AID_DBUS, AID_INET, AID_SHELL }; + struct __user_cap_header_struct header; + struct __user_cap_data_struct cap; + + setgroups(sizeof(groups)/sizeof(groups[0]), groups); + + prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0); + + setgid(AID_DHCP); + setuid(AID_DHCP); + header.version = _LINUX_CAPABILITY_VERSION; + header.pid = 0; + cap.effective = cap.permitted = + (1 << CAP_NET_ADMIN) | (1 << CAP_NET_RAW) | + (1 << CAP_NET_BROADCAST) | (1 << CAP_NET_BIND_SERVICE); + cap.inheritable = 0; + capset(&header, &cap); +} +#endif /* __ANDROID__ */ + int main(int argc, char **argv) { @@ -1417,6 +1447,10 @@ main(int argc, char **argv) #endif char ifn[IF_NAMESIZE]; +#if defined(__ANDROID__) + switch_user(); +#endif // __ANDROID__ + /* Test for --help and --version */ if (argc > 1) { if (strcmp(argv[1], "--help") == 0) { @@ -1746,11 +1780,15 @@ main(int argc, char **argv) goto exit_failure; } - /* Ensure we have the needed directories */ +#if !defined(__ANDROID__) + /* Ensure we have the needed directories + * On Android, we assume that these directories have been created + * by calls to mkdir in an init.rc file. */ if (mkdir(RUNDIR, 0755) == -1 && errno != EEXIST) logger(&ctx, LOG_ERR, "mkdir `%s': %m", RUNDIR); if (mkdir(DBDIR, 0755) == -1 && errno != EEXIST) logger(&ctx, LOG_ERR, "mkdir `%s': %m", DBDIR); +#endif /* __ANDROID__ */ opt = O_WRONLY | O_CREAT | O_NONBLOCK; #ifdef O_CLOEXEC |