diff options
Diffstat (limited to 'util.c')
| -rw-r--r-- | util.c | 141 |
1 files changed, 58 insertions, 83 deletions
@@ -2,7 +2,7 @@ * Common "util" functions * This file is part of the dmidecode project. * - * Copyright (C) 2002-2017 Jean Delvare <jdelvare@suse.de> + * Copyright (C) 2002-2018 Jean Delvare <jdelvare@suse.de> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -59,7 +59,6 @@ static int myread(int fd, u8 *buf, size_t count, const char *prefix) { if (errno != EINTR) { - close(fd); perror(prefix); return -1; } @@ -70,7 +69,6 @@ static int myread(int fd, u8 *buf, size_t count, const char *prefix) if (r2 != count) { - close(fd); fprintf(stderr, "%s: Unexpected end of file\n", prefix); return -1; } @@ -90,19 +88,17 @@ int checksum(const u8 *buf, size_t len) /* * Reads all of file from given offset, up to max_len bytes. - * A buffer of max_len bytes is allocated by this function, and + * A buffer of at most max_len bytes is allocated by this function, and * needs to be freed by the caller. * This provides a similar usage model to mem_chunk() * - * Returns pointer to buffer of max_len bytes, or NULL on error, and + * Returns a pointer to the allocated buffer, or NULL on error, and * sets max_len to the length actually read. - * */ void *read_file(off_t base, size_t *max_len, const char *filename) { + struct stat statbuf; int fd; - size_t r2 = 0; - ssize_t r; u8 *p; /* @@ -116,12 +112,20 @@ void *read_file(off_t base, size_t *max_len, const char *filename) return NULL; } - if (lseek(fd, base, SEEK_SET) == -1) + /* + * Check file size, don't allocate more than can be read. + */ + if (fstat(fd, &statbuf) == 0) { - fprintf(stderr, "%s: ", filename); - perror("lseek"); - p = NULL; - goto out; + if (base >= statbuf.st_size) + { + fprintf(stderr, "%s: Can't read data beyond EOF\n", + filename); + p = NULL; + goto out; + } + if (*max_len > (size_t)statbuf.st_size - base) + *max_len = statbuf.st_size - base; } if ((p = malloc(*max_len)) == NULL) @@ -130,49 +134,67 @@ void *read_file(off_t base, size_t *max_len, const char *filename) goto out; } - do + if (lseek(fd, base, SEEK_SET) == -1) { - r = read(fd, p + r2, *max_len - r2); - if (r == -1) - { - if (errno != EINTR) - { - perror(filename); - free(p); - p = NULL; - goto out; - } - } - else - r2 += r; + fprintf(stderr, "%s: ", filename); + perror("lseek"); + goto err_free; } - while (r != 0); - *max_len = r2; + if (myread(fd, p, *max_len, filename) == 0) + goto out; + +err_free: + free(p); + p = NULL; + out: - close(fd); + if (close(fd) == -1) + perror(filename); return p; } +#ifdef USE_MMAP +static void safe_memcpy(void *dest, const void *src, size_t n) +{ +#ifdef USE_SLOW_MEMCPY + size_t i; + + for (i = 0; i < n; i++) + *((u8 *)dest + i) = *((const u8 *)src + i); +#else + memcpy(dest, src, n); +#endif /* USE_SLOW_MEMCPY */ +} +#endif /* USE_MMAP */ + /* * Copy a physical memory chunk into a memory buffer. * This function allocates memory. */ void *mem_chunk(off_t base, size_t len, const char *devmem) { - void *p; + struct stat statbuf; + void *p = NULL; int fd; #ifdef USE_MMAP - struct stat statbuf; off_t mmoffset; void *mmp; #endif - if ((fd = open(devmem, O_RDONLY)) == -1) + /* + * Safety check: if running as root, devmem is expected to be a + * character device file. + */ + if ((fd = open(devmem, O_RDONLY)) == -1 + || fstat(fd, &statbuf) == -1 + || (geteuid() == 0 && !S_ISCHR(statbuf.st_mode))) { - perror(devmem); - return NULL; + fprintf(stderr, "Can't read memory from %s\n", devmem); + if (fd == -1) + return NULL; + goto out; } if ((p = malloc(len)) == NULL) @@ -182,13 +204,6 @@ void *mem_chunk(off_t base, size_t len, const char *devmem) } #ifdef USE_MMAP - if (fstat(fd, &statbuf) == -1) - { - fprintf(stderr, "%s: ", devmem); - perror("stat"); - goto err_free; - } - /* * mmap() will fail with SIGBUS if trying to map beyond the end of * the file. @@ -214,7 +229,7 @@ void *mem_chunk(off_t base, size_t len, const char *devmem) if (mmp == MAP_FAILED) goto try_read; - memcpy(p, (u8 *)mmp + mmoffset, len); + safe_memcpy(p, (u8 *)mmp + mmoffset, len); if (munmap(mmp, mmoffset + len) == -1) { @@ -247,46 +262,6 @@ out: return p; } -int write_dump(size_t base, size_t len, const void *data, const char *dumpfile, int add) -{ - FILE *f; - - f = fopen(dumpfile, add ? "r+b" : "wb"); - if (!f) - { - fprintf(stderr, "%s: ", dumpfile); - perror("fopen"); - return -1; - } - - if (fseek(f, base, SEEK_SET) != 0) - { - fprintf(stderr, "%s: ", dumpfile); - perror("fseek"); - goto err_close; - } - - if (fwrite(data, len, 1, f) != 1) - { - fprintf(stderr, "%s: ", dumpfile); - perror("fwrite"); - goto err_close; - } - - if (fclose(f)) - { - fprintf(stderr, "%s: ", dumpfile); - perror("fclose"); - return -1; - } - - return 0; - -err_close: - fclose(f); - return -1; -} - /* Returns end - start + 1, assuming start < end */ u64 u64_range(u64 start, u64 end) { |