63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
/*
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* gcc unlinkat_failure.c -o unlinkat_failure.so -shared -ldl
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* LD_PRELOAD=./unlinkat_failure.so FAILURE_PATH=/etc/shadow ./test /etc/shadow
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*/
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#define _GNU_SOURCE
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#include <dlfcn.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <stdarg.h>
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#include <fcntl.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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typedef int (*unlinkat_type) (int dirfd, const char *pathname, int flags);
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static unlinkat_type next_unlinkat;
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static const char *failure_path = NULL;
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static dev_t failure_dev = -1;
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static ino_t failure_ino = -1;
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int unlinkat (int dirfd, const char *pathname, int flags)
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{
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if (NULL == next_unlinkat)
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{
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next_unlinkat = dlsym (RTLD_NEXT, "unlinkat");
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assert (NULL != next_unlinkat);
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}
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if (NULL == failure_path) {
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struct stat sb;
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failure_path = getenv ("FAILURE_PATH");
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if (NULL == failure_path) {
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fputs ("No FAILURE_PATH defined\n", stderr);
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}
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if (lstat (failure_path, &sb) != 0) {
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fputs ("Can't lstat FAILURE_PATH\n", stderr);
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}
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failure_dev = sb.st_dev;
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failure_ino = sb.st_ino;
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}
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if ( (NULL != pathname)
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&& (NULL != failure_path)) {
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struct stat sb;
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if ( (fstatat (dirfd, pathname, &sb, flags) == 0)
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&& (sb.st_dev == failure_dev)
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&& (sb.st_ino == failure_ino)) {
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fprintf (stderr, "unlinkat FAILURE %s\n", failure_path);
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errno = EBUSY;
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return -1;
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}
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}
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return next_unlinkat (dirfd, pathname, flags);
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}
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