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426311f440
The default sysfs path is always set to '/sys' unless the SYSFS_ROOT environment variable is defined. To address security concerns, secure_getenv() is used within util_path_sysfs() to protect against malicious values in SYSFS_ROOT. Additionally, constructing the sysfs path dynamically in an allocated buffer, rather than using a fixed-size buffer, helps prevent potential buffer overflows. These modifications also significantly improve testability by allowing sysfs read and write operations to be redirected to an alternative file path, which enables testing without affecting the active system state. Signed-off-by: Jan Polensky <japo@linux.ibm.com> Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
144 lines
2.7 KiB
C
144 lines
2.7 KiB
C
/*
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* ipl_tools - Linux for System z reipl and shutdown tools
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*
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* Shared system functions
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*
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* Copyright IBM Corp. 2008, 2017
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*
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* s390-tools is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#include "lib/util_path.h"
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#include "ipl_tools.h"
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/*
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* Check if we are running in an LPAR environment
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*/
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int is_lpar(void)
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{
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size_t bytes_read;
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char buf[2048];
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int rc = 0;
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FILE *fh;
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fh = fopen("/proc/cpuinfo", "r");
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if (fh == NULL)
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ERR_EXIT_ERRNO("Could not open \"/proc/cpuinfo\"");
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bytes_read = fread(buf, 1, sizeof(buf), fh);
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if (bytes_read == 0)
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ERR_EXIT("Could not read \"/proc/cpuinfo\"");
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buf[bytes_read] = '\0';
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if (strstr(buf, "version = FF") == NULL)
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rc = 1;
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fclose(fh);
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return rc;
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}
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/*
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* Check whether we are started as root
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*/
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int is_root(void)
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{
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if (geteuid() == 0)
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return 1;
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else
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return 0;
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}
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/*
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* Convert a string to lower case
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*/
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void strlow(char *s)
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{
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while (*s) {
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*s = tolower(*s);
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s++;
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}
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}
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/*
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* Read a string from a particular file
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*/
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void read_str(char *string, const char *path, size_t len)
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{
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size_t rc;
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FILE *fh;
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fh = fopen(path, "rb");
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if (fh == NULL)
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ERR_EXIT_ERRNO("Could not open \"%s\"", path);
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rc = fread(string, 1, len - 1, fh);
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if (rc == 0 && ferror(fh))
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ERR_EXIT_ERRNO("Could not read \"%s\"", path);
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fclose(fh);
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string[rc] = 0;
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if (string[strlen(string) - 1] == '\n')
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string[strlen(string) - 1] = 0;
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}
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/*
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* Read a string from a particular /sys/firmware file
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*/
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void read_fw_str(char *string, const char *file, size_t len)
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{
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char *path;
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path = util_path_sysfs("firmware/%s", file);
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read_str(string, path, len);
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free(path);
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}
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/*
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* Print content of a file (path = dir/file)
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*/
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void print_fw_str(const char *fmt, const char *dir, const char *file)
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{
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char path[PATH_MAX], str[4096];
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snprintf(path, sizeof(path), "%s/%s", dir, file);
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read_fw_str(str, path, sizeof(str));
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printf(fmt, str);
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}
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/*
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* Write a string to a file
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*/
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void write_str(char *string, char *file)
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{
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char value[4096];
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char *path;
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int fh;
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path = util_path_sysfs("firmware/%s", file);
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snprintf(value, sizeof(value), "%s\n", string);
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fh = open(path, O_WRONLY);
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if (fh < 0)
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ERR_EXIT_ERRNO("Could not open \"%s\"", file);
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if (write(fh, value, strlen(value)) < 0)
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ERR_EXIT_ERRNO("Could not set \"%s\"", file);
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close(fh);
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free(path);
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}
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/*
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* Write a string to a file and return ERRNO
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*/
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int write_str_errno(char *string, char *file)
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{
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char value[4096];
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char *path;
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int fh;
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path = util_path_sysfs("firmware/%s", file);
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snprintf(value, sizeof(value), "%s\n", string);
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fh = open(path, O_WRONLY);
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if (fh < 0)
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return errno;
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if (write(fh, value, strlen(value)) < 0)
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return errno;
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close(fh);
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free(path);
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return 0;
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}
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