mirror of
https://github.com/topjohnwu/Magisk.git
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121 lines
3.1 KiB
C++
121 lines
3.1 KiB
C++
#include <sys/xattr.h>
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#include <utils.hpp>
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#include <selinux.hpp>
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using namespace std;
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// Stub implementation
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static int stub(const char *) { return 0; }
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static int stub(const char *, const char *) { return 0; }
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static int stub(const char *, char **ctx) {
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*ctx = strdup("");
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return 0;
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}
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static int stub(int, const char *) { return 0; }
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static int stub(int, char **ctx) {
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*ctx = strdup("");
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return 0;
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}
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// Builtin implementation
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static void __freecon(char *s) {
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free(s);
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}
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static int __setcon(const char *ctx) {
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int fd = open("/proc/self/attr/current", O_WRONLY | O_CLOEXEC);
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if (fd < 0)
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return fd;
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size_t len = strlen(ctx) + 1;
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int rc = write(fd, ctx, len);
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close(fd);
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return rc != len;
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}
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static int __getfilecon(const char *path, char **ctx) {
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char buf[1024];
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int rc = syscall(__NR_getxattr, path, XATTR_NAME_SELINUX, buf, sizeof(buf) - 1);
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if (rc >= 0)
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*ctx = strdup(buf);
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return rc;
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}
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static int __lgetfilecon(const char *path, char **ctx) {
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char buf[1024];
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int rc = syscall(__NR_lgetxattr, path, XATTR_NAME_SELINUX, buf, sizeof(buf) - 1);
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if (rc >= 0)
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*ctx = strdup(buf);
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return rc;
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}
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static int __fgetfilecon(int fd, char **ctx) {
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char buf[1024];
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int rc = syscall(__NR_fgetxattr, fd, XATTR_NAME_SELINUX, buf, sizeof(buf) - 1);
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if (rc >= 0)
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*ctx = strdup(buf);
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return rc;
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}
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static int __setfilecon(const char *path, const char *ctx) {
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return syscall(__NR_setxattr, path, XATTR_NAME_SELINUX, ctx, strlen(ctx) + 1, 0);
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}
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static int __lsetfilecon(const char *path, const char *ctx) {
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return syscall(__NR_lsetxattr, path, XATTR_NAME_SELINUX, ctx, strlen(ctx) + 1, 0);
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}
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static int __fsetfilecon(int fd, const char *ctx) {
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return syscall(__NR_fsetxattr, fd, XATTR_NAME_SELINUX, ctx, strlen(ctx) + 1, 0);
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}
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// Function pointers
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void (*freecon)(char *) = __freecon;
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int (*setcon)(const char *) = stub;
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int (*getfilecon)(const char *, char **) = stub;
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int (*lgetfilecon)(const char *, char **) = stub;
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int (*fgetfilecon)(int, char **) = stub;
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int (*setfilecon)(const char *, const char *) = stub;
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int (*lsetfilecon)(const char *, const char *) = stub;
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int (*fsetfilecon)(int, const char *) = stub;
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void getfilecon_at(int dirfd, const char *name, char **con) {
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char path[4096];
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fd_pathat(dirfd, name, path, sizeof(path));
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if (lgetfilecon(path, con))
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*con = strdup("");
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}
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void setfilecon_at(int dirfd, const char *name, const char *con) {
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char path[4096];
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fd_pathat(dirfd, name, path, sizeof(path));
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lsetfilecon(path, con);
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}
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void selinux_builtin_impl() {
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setcon = __setcon;
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getfilecon = __getfilecon;
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lgetfilecon = __lgetfilecon;
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fgetfilecon = __fgetfilecon;
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setfilecon = __setfilecon;
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lsetfilecon = __lsetfilecon;
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fsetfilecon = __fsetfilecon;
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}
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void dload_selinux() {
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if (access("/system/lib/libselinux.so", F_OK))
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return;
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/* We only check whether libselinux.so exists but don't dlopen.
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* For some reason calling symbols returned from dlsym
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* will result to SEGV_ACCERR on some devices.
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* Always use builtin implementations for SELinux stuffs. */
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selinux_builtin_impl();
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}
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